zotero-db/storage/LLCBKANS/.zotero-ft-cache

IRIG STANDARD 106-17
TELEMETRY GROUP
TELEMETRY STANDARDS
ABERDEEN TEST CENTER DUGWAY PROVING GROUND
REAGAN TEST SITE REDSTONE TEST CENTER WHITE SANDS MISSILE RANGE YUMA PROVING GROUND
NAVAL AIR WARFARE CENTER AIRCRAFT DIVISION NAVAL AIR WARFARE CENTER WEAPONS DIVISION NAVAL UNDERSEA WARFARE CENTER DIVISION, KEYPORT NAVAL UNDERSEA WARFARE CENTER DIVISION, NEWPORT
PACIFIC MISSILE RANGE FACILITY 30TH SPACE WING 45TH SPACE WING 96TH TEST WING 412TH TEST WING
ARNOLD ENGINEERING DEVELOPMENT COMPLEX NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
DISTRIBUTION A: APPROVED FOR PUBLIC RELEASE DISTRIBUTION IS UNLIMITED

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DOCUMENT 106-17
TELEMETRY STANDARDS
July 2017
Prepared by
TELEMETRY GROUP
Published by Secretariat Range Commanders Council US Army White Sands Missile Range, New Mexico 88002-5110

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Telemetry Standards, IRIG Standard 106-17 Table of Contents, July 2017

TABLE OF CONTENTS

Changes in This Edition.................................................................................................................. v Preface........................................................................................................................................... vii

CHAPTER 1: CHAPTER 2: * CHAPTER 3: CHAPTER 4: CHAPTER 5: CHAPTER 6: * CHAPTER 7: CHAPTER 8: CHAPTER 9: * CHAPTER 10: * CHAPTER 11: † CHAPTER 21: † CHAPTER 22: † CHAPTER 23: † CHAPTER 24: † CHAPTER 25: † CHAPTER 26: † CHAPTER 27: † CHAPTER 28: †

CHAPTERS Introduction Transmitter and Receiver Systems Frequency Division Multiplexing Telemetry Standards Pulse Code Modulation Standards Digitized Audio Telemetry Standard Recorder & Reproducer Command and Control Packet Telemetry Downlink Digital Data Bus Acquisition Formatting Standard Telemetry Attributes Transfer Standard Digital On-board Recorder Standard Recorder Data Packet Format Standard Telemetry Network Standard Introduction Network-Based Protocol Suite Metadata Configuration Message Formats Management Resources TmNSDataMessage Transfer Protocol Radio Frequency Network Access Layer Radio Frequency Network Management

APPENDIXES Beginning with RCC 106-17, the appendixes that were previously stand-alone documents are now integrated with the chapters that cover the same material. This does not include four appendixes that are retired but maintained for historical purposes; these four remain stand-alone files and are renamed as annexes. The following lists new locations for the appendixes.

Appendix A, Frequency Considerations for Telemetry Appendix B, Use Criteria for Frequency Division Multiplexing Appendix C, PCM Standards (Additional Information and
Recommendations) Appendix D, Magnetic Tape Recorder and Reproducer
Information and Use Criteria Appendix E, Deleted (Available Transducer Documentation) Appendix F, Continuously Variable Slope Delta Modulation Appendix G, ADARIO Data Block Field Definitions Appendix H, Application of the Telemetry Attributes Transfer
Standard Appendix I, Telemetry Attributes Transfer Standard Cover Sheet

Chapter 2, Appendix 2-A Chapter 3, Appendix 3-A Chapter 4, Appendix 4-A
Annex A-2
none Chapter 5, Appendix 5-A Annex A-3 Chapter 9, Appendix 9-A
Chapter 9, Appendix 9-B

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Telemetry Standards, IRIG Standard 106-17 Table of Contents, July 2017

Appendix J, Telemetry Attributes Transfer Standard Format Example
Appendix K, Pulse Amplitude Modulation Standards Appendix L, Asynchronous Recorder Multiplexer Output Re-
constructor (ARMOR) Appendix M, Properties of the Differential Encoder Specified in
IRIG Standard 106 for OQPSK Modulations Appendix N, Telemetry Transmitter Command and Control
Protocol * Appendix O, Floating Point Formats Appendix P, Derived Parameter Specification Appendix Q, Extended Binary Golay Code Appendix R, Low-Density Parity Check Code for Telemetry
Systems Appendix S, Space-Time Coding for Telemetry Systems

Chapter 9, Appendix 9-C
Annex A-1 Annex A-4
Chapter 2, Appendix 2-B
Chapter 2, Appendix 2-C
Chapter 9, Appendix 9-D Chapter 9, Appendix 9-E Chapter 7, Appendix 7-A Chapter 2, Appendix 2-D
Chapter 2, Appendix 2-E

* Changed † New

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Telemetry Standards, IRIG Standard 106-17 Table of Contents, July 2017
Changes in This Edition
This document is an updated version of and replaces Range Commanders Council (RCC) Document 106-15 (Part 1: Telemetry Standards [July 2015]). The RCC Telemetry Group (TG) made an extensive effort to produce a well-coordinated and useful document. The following is a summary of these efforts.
a. Task TG-128: 2017 Updates to Digital Telemetry Recorder Standards OBJECTIVE/SCOPE: Update IRIG 106 Chapter 6, 9, 10 to include data recorder capabilities required by the RCC members. Update Test Method (118) and Handbook (123).
b. Task TG-131: Define Interference Protection Criteria (IPC) for RF Telemetry Systems OBJECTIVE/SCOPE: Telemetry operations continue to be threatened by new sources of RF interference from services sharing the telemetry bands or operating in adjacent bands. The Telemetry Standards do not contain any guidance for determining appropriate levels of protection to ensure our systems will not be impacted by these sources of interference. This task seeks to define the process and criteria to be used for evaluating potential interference to Range telemetry receiving systems.
c. Task TG-133: Updates to TMATS for 106-17 OBJECTIVE/SCOPE: To enhance the content of the Telemetry Attributes Transfer Standard (TMATS) as needed to keep it current with the data standards in the remainder of 106.
d. Task TG-139: Define PCM Clocking standards for 106-17 OBJECTIVE/SCOPE: Define clocking standards for ground equipment that process chapter 4 NRZ-L PCM.
e. Task TG-140: Update 106-17 Appendix N Transmitter and Receiver Commands OBJECTIVE/SCOPE: Update RCC Document IRIG 106, Appendix N to define additional transmitter commands required to be common at the MRTFBs to support realtime command and control of serial streaming telemetry (SST) transmitter characteristics. This task will also define TM receiver commands for interoperability.
f. Task TG-141: Update IRIG 106 with Standards for Data Quality Metrics (DQM) and Data Quality Encapsulation (DQE) for use in Telemetry Receivers OBJECTIVE/SCOPE: Define a Data Quality Metric (DQM) that correlates with telemetry link Bit Error Performance (BEP) and also define a Data Quality Encapsulation (DQE) standard that defines how to transport DQM with the received telemetry data.
g. Task TG-143: IRIG 106 Ch. 21-28 Publication OBJECTIVE/SCOPE: (1) Incorporate group and industry comments. (2) Publish Chapters 21 through 28 of IRIG 106
h. Task TG-144: Update IRIG 106 Chapter 7.
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Telemetry Standards, IRIG Standard 106-17 Table of Contents, July 2017
OBJECTIVE/SCOPE: Update Chapter 7 and TMATS in chapter 9 to support defining a subset of the PCM minor frame for chapter 7 data. Make chapter 7 and appendix Q clearer on how to implement chapter 7 compliant systems.
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Telemetry Standards, IRIG Standard 106-17 Table of Contents, July 2017

Preface
The TG of the RCC has prepared this document to foster the compatibility of telemetry transmitting, receiving, and signal processing equipment at the member ranges under the cognizance of the RCC. The range commanders highly recommend that telemetry equipment operated by the ranges and telemetry equipment used in programs that require range support conform to these standards.
These standards do not necessarily define the existing capability of any test range, but constitute a guide for the orderly implementation of telemetry systems for both ranges and range users. The scope of capabilities attainable with the utilization of these standards requires the careful consideration of tradeoffs. Guidance concerning these tradeoffs is provided in the text. The standards provide the necessary criteria on which to base equipment design and modification. The ultimate purpose is to ensure efficient spectrum utilization, interference-free operation, interoperability between ranges, and compatibility of range user equipment with the ranges.
This standard is complemented by a companion series: RCC Document 118, Test Methods for Telemetry Systems and Subsystems; RCC Document 119, Telemetry Applications Handbook; RCC Document 123, IRIG 106 Chapter 10 Programmers Handbook; and RCC Document 124, Telemetry Attributes Transfer Standard (TMATS) Handbook.
The policy of the TG is to update the telemetry standards and test methods documents as required to be consistent with advances in technology.
Please direct any questions to:

Secretariat, Range Commanders Council

ATTN: CSTE-WS-RCC

1510 Headquarters Avenue

White Sands Missile Range, New Mexico 88002-5110

Telephone: (575) 678-1107, DSN 258-1107

E-mail:

usarmy.wsmr.atec.list.rcc@mail.mil

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Telemetry Standards, IRIG Standard 106-17 Table of Contents, July 2017
****** NOTHING FOLLOWS ******
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Telemetry Standards, RCC Standard 106-17 Chapter 1, July 2017
CHAPTER 1 Introduction
The Telemetry Standards address the here-to-date conventional methods, techniques, and practices affiliated with aeronautical telemetry applicable to the member RCC ranges. The first 11 chapters are generally devoted to a different element of the telemetry system or process. Chapters 21 through 28 address the topic of network telemetry. These chapters are to be used together to define the various aspects of network telemetry.
Reference documents are identified at the point of reference. Commonly used terms are defined in standard reference glossaries and dictionaries. Definitions of terms with special applications are included when the term first appears, generally in appendices of individual chapters. Radio frequency terms are defined in the Manual of Regulations and Procedures for Federal Radio Frequency Management. Copies of that manual may be obtained from:
Executive Secretary, Interdepartmental Radio Advisory Committee (IRAC) U.S. Department of Commerce, National Telecommunications and Information
Administration (NTIA) Room 1605, HCHB Building 14th and Constitution Avenue, N.W. Washington, D.C. 20230
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Telemetry Standards, RCC Standard 106-17 Chapter 1, July 2017
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

CHAPTER 2 Transmitter and Receiver Systems

Acronyms ..................................................................................................................................... vii

Chapter 2. Transmitter and Receiver Systems................................................................... 2-1

2.1 Radio Frequency Standards for Telemetry ...................................................................... 2-1 2.2 Bands................................................................................................................................ 2-1

2.2.1 2.2.2 2.2.3 2.2.4 2.2.5 2.2.6

Allocation of the Lower L-Band (1435 to 1535 MHz)........................................ 2-2 Allocation of the Lower S-Band (2200 to 2300 MHz) ........................................ 2-2 Allocation of the Upper S-Band (2310 to 2395 MHz) ........................................ 2-3 Allocation of the Lower C-Band (4400 to 4940 MHz)........................................ 2-3 Allocation of the Middle C-Band (5091 to 5150 MHz) ...................................... 2-3 Allocation of the Upper C-Band (5925 to 6700 MHz) ........................................ 2-3

2.3 Telemetry Transmitter Systems ....................................................................................... 2-3

2.3.1 2.3.2 2.3.3 2.3.4 2.3.5 2.3.6 2.3.7

Center Frequency Tolerance ................................................................................ 2-3 Output Power ....................................................................................................... 2-4 Modulation ........................................................................................................... 2-4 Spurious Emission and Interference Limits ....................................................... 2-13 Operational Flexibility ....................................................................................... 2-13 Modulated Transmitter Bandwidth .................................................................... 2-13 Valid Center Frequencies Near Telemetry Band Edges .................................... 2-14

2.4 Telemetry Receiver Systems.......................................................................................... 2-14

2.4.1 2.4.2 2.4.3 2.4.4 2.4.5 2.4.6 2.4.7

Spurious Emissions............................................................................................ 2-14 Frequency Tolerance.......................................................................................... 2-15 Receiver Phase Noise......................................................................................... 2-15 Spurious Responses ........................................................................................... 2-15 Operational Flexibility ....................................................................................... 2-15 Intermediate Frequency Bandwidths ................................................................. 2-15 C-band Downconversion ................................................................................... 2-16

2.5 Codes for Telemetry Systems ........................................................................................ 2-16

2.5.1 2.5.2

Low-Density Parity-Check Code....................................................................... 2-16 Space-Time Code............................................................................................... 2-17

2.6 Randomization Methods for Telemetry Systems........................................................... 2-17

2.6.1 2.6.2 2.6.3

Introduction........................................................................................................ 2-17 Randomizer Types ............................................................................................. 2-17 Randomizer Application .................................................................................... 2-17

2.7 Data Quality Metrics and Data Quality Encapsulation.................................................. 2-18 2.8 Interference Protection Criteria for Aeronautical Mobile Telemetry Systems.............. 2-18

Appendix 2-A. Frequency Considerations for Telemetry.................................................. A-1

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

A.1. Purpose............................................................................................................................ A-1 A.2. Scope............................................................................................................................... A-1

A.2.a. A.2.b. A.2.c.

Definitions........................................................................................................... A-1 Modulation methods ........................................................................................... A-1 Other Notations ................................................................................................... A-2

A.3. Authorization to Use a Telemetry System ...................................................................... A-2

A.3.a. RF Spectrum Support Certification .................................................................... A-2 A.3.b. Frequency Authorization .................................................................................... A-3

A.4. Frequency Usage Guidance ............................................................................................ A-4

A.4.a. A.4.b. A.4.c. A.4.d.

Minimum Frequency Separation......................................................................... A-4 Geographical Separation ..................................................................................... A-8 Multicarrier Operation ........................................................................................ A-8 Transmitter Antenna System Emission Testing.................................................. A-8

A.5. Bandwidth ....................................................................................................................... A-8

A.5.a. A.5.b. A.5.c. A.5.d. A.5.e. A.5.f. A.5.g. A.5.h.

Concept ............................................................................................................... A-9 Bandwidth Estimation and Measurement ......................................................... A-10 Other Bandwidth Measurement Methods ......................................................... A-12 Spectral Equations ............................................................................................ A-14 Receiver Bandwidth.......................................................................................... A-16 Receiver Noise Bandwidth ............................................................................... A-17 Symmetry.......................................................................................................... A-17 FM Transmitters (alternating current-coupled) ................................................ A-17

A.6. Spectral Occupancy Limits ........................................................................................... A-17

A.6.a. Spectral Mask.................................................................................................... A-17 A.6.b. Spectral Mask Examples................................................................................... A-19

A.7. Technical Characteristics of Digital Modulation Methods ........................................... A-20 A.8. FQPSK-B and FQPSK-JR Characteristics.................................................................... A-21 A.9. SOQPSK-TG Characteristics........................................................................................ A-25 A.10. Advanced Range Telemetry Continuous Phase Modulation Characteristics ............... A-26 A.11. PCM/FM ....................................................................................................................... A-27 A.12. Valid Center Frequencies Near Telemetry Band Edges ............................................... A-28

Appendix 2.B. Properties of the Differential Encoder Specified in IRIG Standard 106 for OQPSK Modulations........................................................ B-33
B.1. Introduction................................................................................................................... B-33 B.2. The Need For Differential Encoding ............................................................................ B-33 B.3. A Simple Solution To The Carrier Phase Ambiguity Problem..................................... B-35 B.4. Immunity to Carrier Phase Rotation ............................................................................. B-38 B.5. Initial Values ................................................................................................................. B-40 B.6. Error Propagation.......................................................................................................... B-41 B.7. Recursive Processing and Code Memory ..................................................................... B-41 B.8. Frequency Impulse Sequence Mapping for SOQPSK .................................................. B-43

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

B.9. Summary ....................................................................................................................... B-44 B.10. System-Level Software Reference Implementation of Differential Encoder Defined in IRIG Standard 106 for FQPSK and SOQPSK Modulations..................................................... B-44

B.10.a. B.10.b. B.10.c.

Introduction ........................................................................................................B-44 Matlab Workspace Operation ............................................................................B-45 Script For Modules ............................................................................................B-46

Appendix 2-C. Telemetry Transmitter Command and Control Protocol........................ C-1

C.1. Introduction..................................................................................................................... C-1 C.2. Command Line Interface ................................................................................................ C-1

C.2.a. C.2.b.

User Command Line Interface.............................................................................C-1 Optional Programming Interface .........................................................................C-1

C.3. Initialization .................................................................................................................... C-2 C.4. Basic Command Set ........................................................................................................ C-2

C.4.a. C.4.b.

Basic Command Set Summary ............................................................................C-2 Commands: Basic Command Set........................................................................C-3

C.5. Extended Command Set................................................................................................ C-10

C.5.a. C.5.b.

Extended Command Set Summary ....................................................................C-10 Commands: Extended Command Set ................................................................C-11

C.6. Transmitter Communication Example.......................................................................... C-14 C.7. Non-Standard Commands ............................................................................................. C-14 C.8. Physical Layer(s) .......................................................................................................... C-14

Appendix 2-D. Low-Density Parity-Check Codes for Telemetry Systems....................... D-1

D.1. Background ..................................................................................................................... D-1 D.2. Code Description ............................................................................................................ D-1 D.3. Parity Check Matrices..................................................................................................... D-2 D.4. Encoding ......................................................................................................................... D-9

D.4.a. D.4.b. D.4.c. D.4.d. D.4.e. D.4.f.

Code Rate =1/2, Information Block Size = 1024, M = 512 .............................. D-11 Code Rate =1/2, Information Block Size = 4096, M = 2048 ............................ D-12 Code Rate =2/3, Information Block Size = 1024, M = 256 .............................. D-17 Code Rate =2/3, Information Block Size = 4096, M = 1024 ............................ D-21 Code Rate =4/5, Information Block Size = 1024, M = 128 .............................. D-27 Code Rate =4/5, Information Block Size = 4096, M = 512 .............................. D-34

D.5. Synchronization ............................................................................................................ D-41 D.6. Randomization .............................................................................................................. D-42 D.7. Performance .................................................................................................................. D-43

Appendix 2-E. Space-Time Coding for Telemetry Systems .............................................. E-1
E.1. Code Description .............................................................................................................E-1 E.2. Modulation.......................................................................................................................E-3 E.3. Resources .........................................................................................................................E-4

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
Appendix 2-F. Use of Recommendation ITU-R M.1459 for Protection of AMT Ground Stations from Terrestrial, Airborne, and Satellite Interference ........................................................................................................F-1
F.1. Introduction and Summary ..............................................................................................F-1 F.2. Practical Application of the Rec M.1459 Protection Criteria ..........................................F-1
Appendix 2-G. Standards for Data Quality Metrics and Data Quality Encapsulation .................................................................................................... G-1
G.1. Purpose............................................................................................................................ G-1 G.2. Scope............................................................................................................................... G-1 G.3. Data Quality Metric ........................................................................................................ G-1 G.4. Data Quality Encapsulation Protocol.............................................................................. G-2
Appendix 2-H. Citations........................................................................................................ H-1
Table of Figures
Figure 2-1. FQPSK-JR Baseband Signal Generator............................................................... 2-6 Figure 2-2. Basic SOQPSK .................................................................................................... 2-8 Figure 2-3. SOQPSK Transmitter......................................................................................... 2-10 Figure 2-4. Conceptual CPM Modulator .............................................................................. 2-11 Figure 2-5. Continuous Single-Sideband Phase Noise Power Spectral Density .................. 2-12 Figure A-1. Spectra of 10-Mbps PCM/FM, ARTM CPM, FQPSK-JR, SOQPSK-TG
Signals................................................................................................................. A-4 Figure A-2. 5 Mbps PCM/FM Signals with 11 MHz Center Frequency Separation ............. A-6 Figure A-3. 10 Mbps ARTM CPM Signals with 9 MHz Center Frequency Separation........ A-7 Figure A-4. RNRZ PCM/FM Signal .................................................................................... A-11 Figure A-5. Spectrum Analyzer Calibration of 0-dBc Level ............................................... A-12 Figure A-6. Biφ PCM/PM Signal ......................................................................................... A-13 Figure A-7. FM/AM Signal and Carson’s Rule ................................................................... A-14 Figure A-8. Typical Receiver RLC IF Filter Response (−3 dB Bandwidth = 1 MHz) ........ A-16 Figure A-9. RLC and SAW IF Filters .................................................................................. A-16 Figure A-10. Filtered 5-Mbps RNRZ PCM/FM Signal and Spectral Mask........................... A-19 Figure A-11. Unfiltered 5-Mbps RNRZ PCM/FM Signal and Spectral Mask....................... A-19 Figure A-12. Typical 5-Mbps SOQPSK TG Signal and Spectral Mask ................................ A-20 Figure A-13. Typical 5-Mbps ARTM CPM Signal and Spectral Mask ................................. A-20 Figure A-14. OQPSK Modulator............................................................................................ A-21 Figure A-15. I and Q Constellation ........................................................................................ A-22 Figure A-16. FQPSK Wavelet Eye Diagram.......................................................................... A-22 Figure A-17. FQPSK-B I & Q Eye Diagrams (at Input to IQ Modulator)............................. A-23 Figure A-18. FQPSK-B Vector Diagram ............................................................................... A-23 Figure A-19. 5 Mbps FQPSK-JR Spectrum with Random Input Data and Small (Blue)
and Large (Red) Modulator Errors ................................................................... A-24 Figure A-20. FQPSK-B Spectrum with All 0’s Input and Large Modulator Errors .............. A-24 Figure A-21. FQPSK-JR BEP vs. Eb/N0 ............................................................................... A-25 Figure A-22. Measured SOQPSK-TG Phase Trajectory........................................................ A-25
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
Figure A-23. SOQPSK-TG Power Spectrum (5 Mbps) ......................................................... A-26 Figure A-24. BEP vs. Eb/N0 Performance of 5 Mbps SOQPSK-TG .................................... A-26 Figure A-25. Power Spectrum of 5 Mbps ARTM CPM......................................................... A-27 Figure A-26. BEP vs. Eb/N0 Performance of 5 Mbps ARTM CPM ..................................... A-27 Figure A-27. Power Spectrum of 5 Mbps PCM/FM Signal ................................................... A-28 Figure A-28. BEP vs. Eb/N0 Performance of 5-Mbps PCM/FM with Multi-Symbol Bit
Detector and Three Single-Symbol Receivers/Detectors ................................. A-28 Figure A-29. Spectral Masks at −25 dBm .............................................................................. A-29 Figure A-30. Bit Rate vs. Band Edge Back-off ...................................................................... A-30 Figure B-1. Transmission System .........................................................................................B-34 Figure B-2. OQPSK 106 Symbol-to-Phase Mapping Convention........................................B-34 Figure B-3. Detection Ambiguity..........................................................................................B-35 Figure B-4. QPSK State Timing............................................................................................B-36 Figure B-5. OQPSK State Timing.........................................................................................B-36 Figure B-6. SOQPSK Transmitter.........................................................................................B-43 Figure B-7. OQPSK Transmitter (With Precorder)...............................................................B-44 Figure C-1. Terminal Window for STC-Enabled Transmitter ..............................................C-10 Figure C-2. Typical Terminal Window .................................................................................C-14 Figure D-1. Parity Check Matrix H for (n=2048, k=1024) Rate 1/2...................................... D-4 Figure D-2. Parity Check Matrix H for (n=8192, k=4096) Rate 1/2...................................... D-5 Figure D-3. Parity Check Matrix H for (n=1536, k=1024) Rate 2/3...................................... D-6 Figure D-4. Parity Check Matrix H for (n=6144, k=4096) Rate 2/3...................................... D-7 Figure D-5. Parity Check Matrix H for (n=1280, k=1024) Rate 4/5...................................... D-8 Figure D-6. Parity Check Matrix H for (n=5120, k=4096) Rate 4/5...................................... D-9 Figure D-7. Quasi-Cyclic Encoder Using Feedback Shift Register ..................................... D-10 Figure D-8. ASM/Codeblock Structure................................................................................ D-41 Figure D-9. Codeblock Randomizer..................................................................................... D-42 Figure D-10. LDPC Detection Performance with 4-state Trellis Demodulator ..................... D-43 Figure D-11. LDPC Detection Performance with Symbol-by-Symbol Demodulator............ D-44 Figure E-1. Symbol-to-Phase Mapping for IRIG-106 Offset QPSK Modulation ..................E-1 Figure E-2. Notional Diagram Illustrating the Periodic Insertion of 128 Pilot Bits
Every 3200 Alamouti-Encoded Bits ....................................................................E-3 Figure E-3. A Notional Block Diagram of the Space-Time Code Transmitter ......................E-4 Figure F-1. Excerpt from Article 21 of the International Radio Regulations ......................... F-5 Figure F-2. Geometry of a Geostationary Link Showing (a) Elevation, (b) Azimuth
from a Point T on the Earth.................................................................................. F-8 Figure F-3. Digital Audio Radio Service Downlink Beam Gain Contours ............................ F-9 Figure F-4. Elevation Angles from Surface of the Earth to the 115.2° West Longitude
Orbital Location ................................................................................................. F-10 Figure F-5. FCC Emission Mask for the WCS OOBE Band from 2360 – 2390 MHz......... F-11 Figure F-6. Simulated OOBE Emissions from an LTE Handset .......................................... F-13 Figure F-7. Graphical Representation of the Two-Ray Model ............................................. F-14 Figure F-8. Comparison of Free-Space One-Slope and Two-Ray Propagation Models ...... F-15 Figure F-9. Rayleigh Fading of a Signal Transmitted from a Moving Platform .................. F-17 Figure F-10. S-band Telemetry Signal Received from an Aircraft in Flight.......................... F-17
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

Figure F-11.
Figure F-12.
Figure F-13. Figure F-14. Figure F-15. Figure F-16. Figure F-17.

Rayleigh Distribution as Presented in Figure 2 of Rec M.1459 (Jablonski 2004). ................................................................................................................. F-18 EDX Signal Pro Map of Hypothetical Transmitters and Receivers in the Pax River Region. .............................................................................................. F-21 EDX Signal Pro Path Loss Profile for the TX007 to RX007 Path .................... F-21 Actual Measured Path Loss Data from an NTIA Report (cf. footnote 71)........ F-22 Composite AMT Pattern from Rec M.1459 ...................................................... F-26 Aggregate Interference as a Function of AMT Antenna Pointing Angle .......... F-27 Statgain Pattern .................................................................................................. F-31

Table 2-1. Table 2-3. Table 2-4. Table 2-5. Table 2-6. Table 2-7. Table 2-8. Table A-1. Table A-2. Table A-3. Table A-4. Table A-5. Table B-1. Table B-2. Table B-3. Table B-1. Table C-1. Table C-2. Table D-1. Table D-2. Table D-3. Table D-4. Table D-5. Table D-6. Table D-7. Table D-8. Table D-9. Table D-10. Table D-11. Table F-1. Table G-1.

Table of Tables
Telemetry Frequency Allocations........................................................................ 2-1 FQPSK-B and FQPSK-JR Phase Map................................................................. 2-7 SOQPSK-TG Parameters................................................................................... 2-10 SOQPSK Pre-Coding Table for IRIG-106 Compatibility ................................. 2-10 Dibit to Impulse Area Mapping ......................................................................... 2-11 Standard Receiver Intermediate Frequency Bandwidths................................... 2-15 Interference Protection Criteria by Band and Angle of Arrival......................... 2-18 Coefficients for Minimum Frequency Separation Calculation........................... A-4 B99% for Various Digital Modulation Methods ................................................ A-9 Characteristics of Various Modulation Methods .............................................. A-20 L-Band Frequency Range (10 W, 5 Mbps)....................................................... A-29 Valid Center Frequency, Band Edge Back-Off ................................................ A-31 Constellation Axis Rotations .............................................................................B-35 Response to Run of 1s........................................................................................B-38 SOQPSK Pre-Coding Table for IRIG-106 Compatibility .................................B-43 Script “runDEdemo” Output..............................................................................B-45 Basic Command Set .............................................................................................C-2 Extended Command Set.....................................................................................C-10 Codeblock Length per Information Block Size .................................................. D-2 Submatrix Size per Information Block Size ....................................................... D-2 Generator Matrix Sizes ..................................................................................... D-10 First Rows of Circulants in Generator Matrix, r=1/2, k=1024 ......................... D-11 First Rows of Circulants in Generator Matrix, r=1/2, k=4096 ......................... D-13 First Rows of Circulants in Generator Matrix, r=2/3, k=1024 ......................... D-17 First Rows of Circulants in Generator Matrix, r=2/3, k=4096 ......................... D-21 First Rows of Circulants in Generator Matrix, r=4/5, k=1024 ......................... D-27 First Rows of Circulants in Generator Matrix, r=4/5, k=4096 ......................... D-34 ASM Definition ................................................................................................ D-41 Bandwidth Expansion Factor ............................................................................ D-42 Statgain Formulas .............................................................................................. F-31 BEP Verses DQM ............................................................................................... G-1

vi

µV AFTRCC AM AMT ARTM ASM AWGN BPSK BEP BER Biφ BSS CPFSK CPM CCSDS dB dBc dBi dBm dBW DoD DQE DQM EESS EIRP FCC FEC FM FQPSK Hz IF I/N IPC IRIG ITM kHz LDPC L-R LTE Mbps MCEB MHz MIL-STD MSK NRZ-L

Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
Acronyms
microvolt Aerospace and Flight Test Radio Coordinating Council amplitude modulation aeronautical mobile telemetry Advanced Range Telemetry attached synchronization marker additive white Gaussian noise binary phase shift keying bit error probability bit error rate bi-phase Broadcasting-Satellite Service continuous phase frequency shift keying continuous phase modulation Consultative Committee for Space Data Systems decibel decibels relative to the carrier decibels isotropic decibels referenced to one milliwatt decibels relative to one watt Department of Defense data quality encapsulation data quality metric Earth Exploration-Satellite Services effective isotropic radiated power Federal Communications Commission forward error correction frequency modulation Feher’s quadrature phase shift keying hertz intermediate frequency interference-to-noise ratio interference protection criteria Inter-Range Instrumentation Group Irregular Terrain Model kilohertz low-density parity-check Longley-Rice Long-Term Evolution megabits per second Military Communications - Electronics Board megahertz Military Standard minimum shift keying non-return-to-zero-level
vii

NTIA OOBE OQPSK PAPR PCM PFD PM PSD QPSK RCC RF RLC RNRZ SAW SDARS SHF STC SOQPSK UHF US&P VCO VHF WCS

Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
National Telecommunications and Information Administration out-of-band emission offset quadrature phase shift keying peak-to-average-power-ratio pulse code modulation power flux density phase modulation power spectral density quadrature phase shift keying Range Commanders Council radio frequency resistor-inductor-capacitor randomized non-return-to-zero surface acoustic wave Satellite Digital Audio Radio Service super-high frequency space-time code shaped offset quadrature phase shift keying ultra-high frequency United States and Possessions voltage-controlled oscillator very-high frequency Wireless Communication Service

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

CHAPTER 2

Transmitter and Receiver Systems

2.1 Radio Frequency Standards for Telemetry
These standards provide the criteria to determine equipment and frequency use requirements and are intended to ensure efficient and interference-free use of the radio frequency (RF) spectrum. These standards also provide a common framework for sharing data and providing support for test operations between ranges. The RF spectrum is a limited natural resource; therefore, efficient use of available spectrum is mandatory. In addition, susceptibility to interference must be minimized. Systems not conforming to these standards require justification upon application for frequency allocation, and the use of such systems is highly discouraged. The standards contained herein are derived from the National Telecommunications and Information Administration’s (NTIA) Manual of Regulations and Procedures for Federal Radio Frequency Management.1

2.2 Bands The bands used for telemetry are described in Table 2-1.

Table 2-1. Telemetry Frequency Allocations

Frequency Range (MHz) 1435-1525
1525-1535
2200-2290 2310-2360
2360-2395 4400-4940 5091-5150 5925-6700

Unofficial Designation Lower L-band
Lower L-band
Lower S-band Upper S-band
Upper S-band Lower C-band Middle C-band Upper C-band

Comments Telemetry primary service (part of mobile service) in USA Mobile satellite service (MSS) primary service, telemetry secondary service in USA Telemetry co-primary service in USA Wireless Communications Service (WCS) and Broadcasting-Satellite Service (BSS) primary services, telemetry secondary service in USA Telemetry primary service in USA See Paragraph 2.2.4 See Paragraph 2.2.5 See Paragraph 2.2.6

Refer to: 2.2.1
2.2.1
2.2.2 2.2.3
2.2.3 2.2.4 2.2.5 2.2.6

The 1755-1850 MHz band (unofficially called “upper L-band”) can also be used for telemetry at many test ranges, although it is not explicitly listed as a telemetry band in the NTIA Table of Frequency Allocations.2 The mobile service is a primary service in the 1755-1850 MHz band and telemetry is a part of the mobile service. Since the 1755-1850 MHz band is not considered a standard telemetry band per this document, potential users must coordinate, in

1 National Telecommunications and Information Administration. “Manual of Regulations and Procedures for Federal Radio Frequency Management.” September 2015. May be superseded by update. Retrieved 23 March 2017. Available at https://www.ntia.doc.gov/files/ntia/publications/manual_sep_2015.pdf. 2 Code of Federal Regulations, Table of Frequency Allocations, title 47, sec. 2.106.
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advance, with the individual range(s) and ensure use of this band can be supported at the subject range and that it will meet their technical requirements. While these band designations are common in telemetry parlance, they may have no specific meaning to anyone else. Telemetry assignments are made for testing3 manned and unmanned aircraft, for missiles, space, land, and sea test vehicles, and for rocket sleds and systems carried on such sleds. Telemetry assignments are also made for testing major components of the aforementioned systems.
2.2.1 Allocation of the Lower L-Band (1435 to 1535 MHz) This band is allocated in the United States and Possessions (US&P) for government and
nongovernmental aeronautical telemetry use on a shared basis. The Aerospace and Flight Test Radio Coordinating Council (AFTRCC) coordinates the non-governmental use of this band. The frequencies in this range will be assigned for aeronautical telemetry and associated remotecontrol operations4 for testing of manned or unmanned aircraft, missiles, rocket sleds, and other vehicles or their major components. Authorized usage includes telemetry associated with launching and reentry into the earth's atmosphere as well as any incidental orbiting prior to reentry of manned or unmanned vehicles undergoing flight tests. The following frequencies are shared with flight telemetering mobile stations: 1444.5, 1453.5, 1501.5, 1515.5, 1524.5, and 1525.5 MHz.
2.2.1.1 1435 to 1525 MHz This frequency range is allocated for the exclusive use of aeronautical telemetry in the
United States of America.
2.2.1.2 1525 to 1530 MHz The 1525 to 1530 MHz band was reallocated at the 1992 World Administrative Radio
Conference. The mobile-satellite service is now a primary service in this band. The mobile service, which includes aeronautical telemetry, is now a secondary service in this band.
2.2.1.3 1530 to 1535 MHz The maritime mobile-satellite service is a primary service in the frequency band from
1530 to 1535 MHz.5 The mobile service (including aeronautical telemetry) is a secondary service in this band.
2.2.2 Allocation of the Lower S-Band (2200 to 2300 MHz) No provision is made in this band for the flight testing of manned aircraft.
2.2.2.1 2200 to 2290 MHz These frequencies are shared equally by the United States Government's fixed, mobile,
space research, space operation, and the Earth Exploration-Satellite Services (EESS), and include telemetry associated with launch vehicles, missiles, upper atmosphere research rockets, and space vehicles regardless of their trajectories.
3 A telemetry system as defined here is not critical to the operational (tactical) function of the system. 4 The word used for remote-control operations in this band is telecommand. 5 Reallocated as of 1 January 1990.
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2.2.2.2 2290 to 2300 MHz Allocations in this range are for the space research service (deep space only) on a shared
basis with the fixed and mobile (except aeronautical mobile) services.
2.2.3 Allocation of the Upper S-Band (2310 to 2395 MHz) This band is allocated to the fixed, mobile, radiolocation, and BSS in the United States of
America. Government and nongovernmental telemetry users share this band in a manner similar to that of the L-band. Telemetry assignments are made for flight-testing of manned or unmanned aircraft, missiles, space vehicles, or their major components.
2.2.3.1 2310 to 2360 MHz These frequencies have been reallocated and were auctioned by the Federal
Communications Commission (FCC) in April 1997. The WCS is the primary service in the frequencies 2305-2320 MHz and 2345-2360 MHz. The BSS is the primary service in the 23202345 MHz band. In the 2320-2345 MHz band, the mobile and radiolocation services are allocated on a primary basis until a broadcasting-satellite (sound) service has been brought into use in such a manner as to affect or be affected by the mobile and radiolocation services in those service areas
2.2.3.2 2360 to 2395 MHz The mobile service (including aeronautical telemetry) is a primary service in this band.
2.2.4 Allocation of the Lower C-Band (4400 to 4940 MHz) Telemetry is an operation that is currently allowed under the mobile service allocation.
2.2.5 Allocation of the Middle C-Band (5091 to 5150 MHz) The process of incorporating aeronautical telemetry operations into the NTIA Table of
Frequency Allocations for this band has been initiated but not yet completed.
2.2.6 Allocation of the Upper C-Band (5925 to 6700 MHz) This band is not currently allocated as a government band. The process of incorporating
federal government use of aeronautical telemetry operations into the NTIA Table of Frequency Allocations for this band has been initiated but not yet completed.
2.3 Telemetry Transmitter Systems
Telemetry requirements for air, space, and ground systems are accommodated in the appropriate bands as described in Section 2.2.
2.3.1 Center Frequency Tolerance Unless otherwise dictated by a particular application, the frequency tolerance for a
telemetry transmitter shall be ±0.002% of the transmitter's assigned center frequency. Transmitter designs shall control transient frequency errors associated with startup and power interruptions. During the first second after turn-on, the transmitter output frequency shall be within the occupied bandwidth of the modulated signal at any time when the transmitter output power exceeds −25 decibels (dB) referenced to one milliwatt (dBm). Between 1 and 5 seconds after initial turn-on, the transmitter frequency shall remain within twice the specified limits for the assigned radio frequency. After 5 seconds, the standard frequency tolerance is applicable for
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
any and all operations where the transmitter power output is −25 dBm or greater (or produces a field strength greater than 320 microvolts [µV]/meter at a distance of 30 meters from the transmitting antenna in any direction). Specific uses may dictate tolerances more stringent than those stated.
2.3.2 Output Power Emitted power levels shall always be limited to the minimum required for the application.
The output power shall not exceed 25 watts6. The effective isotropic radiated power (EIRP) shall not exceed 25 watts.
2.3.3 Modulation The traditional modulation methods for aeronautical telemetry are frequency modulation
(FM) and phase modulation (PM). Pulse code modulation (PCM)/FM has been the most popular telemetry modulation since around 1970. The PCM/FM method could also be called filtered continuous phase frequency shift keying (CPFSK). The RF signal is typically generated by filtering the baseband non-return-to-zero-level (NRZ-L) signal and then frequency modulating a voltage-controlled oscillator (VCO). The optimum peak deviation is 0.35 times the bit rate and a good choice for a premodulation filter is a multi-pole linear phase filter with bandwidth equal to 0.7 times the bit rate. Both FM and PM have a variety of desirable features but may not provide the required bandwidth efficiency, especially for higher bit rates. When better bandwidth efficiency is required, the standard methods for digital signal transmission are the Feher’s patented quadrature phase shift keying (FQPSK-B and FQPSK-JR), the shaped offset quadrature phase shift keying (SOQPSK-TG), and the Advanced Range Telemetry (ARTM) continuous phase modulation (CPM). Each of these methods offer constant, or nearly constant, envelope characteristics and are compatible with non-linear amplifiers with minimal spectral regrowth and minimal degradation of detection efficiency. The first three methods (FQPSK-B, FQPSK-JR, and SOQPSK-TG) are interoperable and require the use of the differential encoder described in Subsection 2.3.3.1.1 below. Additional information on this differential encoder is contained in 0. All of these bandwidth-efficient modulation methods require the data to be randomized. Additional characteristics of these modulation methods are discussed in the following paragraphs and in Section A.7.
2.3.3.1 Characteristics of FQPSK-B The FQPSK-B method is described in the Digcom Inc. publication, “FQPSK-B, Revision
A1, Digcom-Feher Patented Technology Transfer Document, January 15, 1999.” This document can be obtained under a license from:
Digcom Inc. 44685 Country Club Drive El Macero, CA 95618 Telephone: 530-753-0738 FAX: 530-753-1788
6 An exemption from this EIRP limit will be considered; however, systems with EIRP levels greater than 25 watts will be considered nonstandard systems and will require additional coordination with affected test ranges.
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2.3.3.1.1 Differential Encoding Differential encoding shall be provided for FQPSK-B, FQPSK-JR, and SOQPSK-TG and
shall be consistent with the following definitions.

The NRZ-L data bit sequence {bn} is sampled periodically by the transmitter at time instants:

t = nTb

n = 0,1, 2, ....

where Tb is the NRZ-L bit period.
Using the bit index values n as references to the beginning of symbol periods, the differential encoder alternately assembles I-channel and Q-channel symbols to form the following sequences:
I 2 , I 4 , I6 ,... and Q3 ,Q5 ,Q7 ,...

according to the following rules:

(2-1)

(2-2)
Where ⊕ denotes the exclusive-or operator, and the bar above a variable indicates the ‘not’ or inversion operator. Q-channel symbols are offset (delayed) relative to I-channel symbols by one bit period.
2.3.3.1.2 Characteristics of FQPSK-JR The FQPSK-JR method is a cross-correlated, constant envelope, spectrum-shaped variant
of FQPSK. It assumes a quadrature modulator architecture and synchronous digital synthesis of the I and Q-channel modulating signals as outlined in Figure 2-1.

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

b(nTb)

Serial/Parallel Differential Encoder Wavelet Assembly
Interpolate

Digital
"-JR"
"-JR"

Analog

DAC DAC

I LPF
To Modulator
Q LPF

Clock x ρ

Clock x ρ ι

rb clock

Figure 2-1. FQPSK-JR Baseband Signal Generator

The FQPSK-JR method utilizes the time domain wavelet functions defined in United States Patent 4,567,6027 with two exceptions. The transition functions used in the cited patent,

G(t

)

=

± 

1

−

K

cos

2



πt

Ts



± 1− K sin 2 πt Ts 

K =1− A =1− 2 2

(2-3)

are replaced with the following transition functions:

(2-4)

where Ts = 2/rb is the symbol period. The digital “JR” spectrum-shaping filter used for each channel is a linear phase, finite impulse response filter. The filter is defined in terms of its impulse response sequence h(n) in
7 Feher, Kamilo, and Shuzo Kato. Correlated signal processor. US Patent 4,567,602. Filed 13 June 1983 and issued 28 January 1986.
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Table 2-2 and assumes a fixed wavelet sample rate of ρ = 6 samples per symbol. The JRequiv column is the aggregate response of the cascaded JRa and JRb filters actually used.

Table 2-2. FQPSK-JR Shaping Filter Definition

Filter Weight

JRequiv

JRa

h(0)

−0.046875

2−2

h(1)

0.109375

h(0)

h(2)

0.265625

h(0)

h(3)

h(2)

-

h(4)

h(1)

-

h(5)

h(0)

-

JRb −(2−3 + 2−4) (2−1 + 2−3)
h(1) h(0)
-

Digital interpolation is used to increase sample rate, moving all alias images created by digital-to-analog conversion sufficiently far away from the fundamental signal frequency range so that out-of-channel noise floors can be well-controlled. The FQPSK-JR reference implementations currently utilize 4-stage Cascade-Integrator-Comb interpolators with unity memory lag factor.8 Interpolation ratio “ι“ is adjusted as a function of bit rate such that fixed cutoff frequency post-digital-to-analog anti-alias filters can be used to cover the entire range of required data rates.9
2.3.3.1.3 Carrier Suppression The remnant carrier level shall be no greater than −30 dB relative to the carrier (dBc).
Additional information of carrier suppression can be seen at Section A.7.
2.3.3.1.4 Quadrature Modulator Phase Map Table 2-3 lists the mapping from the input to the modulator (after differential encoding
and FQPSK-B or FQPSK-JR wavelet assembly) to the carrier phase of the modulator output. The amplitudes in Table 2-3 are ± a, where “a” is a normalized amplitude.

Table 2-3. FQPSK-B and FQPSK-JR Phase Map

I Channel
a −a −a a

Q Channel
a a −a −a

Resultant Carrier Phase 45 degrees 135 degrees 225 degrees 315 degrees

8 Eugene Hogenauer. “An Economical Class of Digital Filters for Decimation and Interpolation” in IEEE Transactions on Acoustics, Speech, and Signal Processing, 29, No. 2 (1981): 155-162. 9 The FQPSK-JR definition does not include a specific interpolation method and a post-D/A filter design; however, it is known that benchmark performance will be difficult to achieve if the combined effects of interpolation and antialias filter produce more than .04 dB excess attenuation at 0.0833 times the input sample rate and more than 1.6 dB of additional attenuation at 0.166 times the sample rate where the input sample rate is referred to the input of the interpolator assuming 6 samples per second.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
2.3.3.2 Characteristics of SOQPSK-TG The SOQPSK method is a family of constant-envelope CPM waveforms.10, 11, 12, 13 It is
most simply described as a non-linear FM modeled as shown in Figure 2-2.

Figure 2-2. Basic SOQPSK

The SOQPSK waveform family is uniquely defined in terms of impulse excitation of a frequency impulse shaping filter function g(t):

where

(2-5)

(2-6)

10 T. J. Hill. “An Enhanced, Constant Envelope, Interoperable Shaped Offset QPSK (SOQPSK) Waveform for Improved Spectral Efficiency.” Paper presented during 36th Annual International Telemetering Conference, San Diego, CA. October 23-26, 2000. 11 Younes B., James Brase, Chitra Patel, and John Wesdock. “An Assessment of Shaped Offset QPSK for Use in NASA Space Network and Ground Network Systems” in Proceedings of the CCSDS RF and Modulation Subpanel 1E Meeting of May 2001 Concerning Bandwidth-Efficient Modulation. CCSDS B20.0-Y-2. June 2001. Retrieved 4 June 2015. Available at http://public.ccsds.org/publications/archive/B20x0y2.pdf. 12 Mark Geoghegan. “Implementation and Performance Results for Trellis Detection of SOQPSK.” Paper presented at the 37th Annual International Telemetering Conference, Las Vegas, NV, October 2001. 13 Marvin Simon. “Bandwidth-Efficient Digital Modulation with Application to Deep Space Communications.” JPL Publication 00-17. June 2001. Retrieved 3 June 2015. Available at http://descanso.jpl.nasa.gov/monograph/series3/complete1.pdf.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

1,

t Ts

≤ T1

w(t)

≡

1 2

  1 + 

  cos 

π



t− Ts T2

T1



   

,



 



T1

<

t Ts

≤ T1 + T2

(2-7)

0,

t Ts

> T1 + T2

The function n(t) is a modified spectral raised cosine filter of amplitude A, rolloff factor

ρ, and an additional time scaling factor B. The function w(t) is a time domain windowing

function that limits the duration of g(t). The amplitude scale factor A is chosen such that

(2-8)

Given a time series binary data sequence
(2-9)
wherein the bits are represented by normalized antipodal amplitudes {+1,−1}, the ternary impulse series is formed with the following mapping rule (see also Geoghegan, Implementation and Simon, Bandwidth), …
(2-10)
that will form a data sequence alphabet of three values {+1,0,−1}. It is important to note that this modulation definition does not establish an absolute relationship between the digital in-band inter-switch trunk signaling (dibits) of the binary data alphabet and transmitted phase as with conventional quadriphase offset quadrature phase shift keying (OQPSK) implementations. In order to achieve interoperability with coherent FQPSK-B demodulators, some form of precoding must be applied to the data stream prior to, or in conjunction with, conversion to the ternary excitation alphabet. The differential encoder defined in Subsection 2.3.3.1.1 fulfills this need; however, to guarantee full interoperability with the other waveform options, the polarity relationship between frequency impulses and resulting frequency or phase change must be controlled. Thus, SOQPSK modulators proposed for this application shall guarantee that an impulse value of (+1) will result in an advancement of the transmitted phase relative to that of the nominal carrier frequency (i.e., the instantaneous frequency is above the nominal carrier).
For purposes of this standard, only one specific variant of SOQPSK and SOQPSK-TG is acceptable. This variant is defined by the parameter values given in Table 2-4.

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Table 2-4.
SOQPSK Type SOQPSK-TG

SOQPSK-TG Parameters

ρ

B

T1

T2

0.70 1.25 1.5 0.50

As discussed above, interoperability with FQPSK-B equipment requires a particular precoding protocol or a functional equivalent thereof. A representative model is shown in Figure 2-3.

Figure 2-3. SOQPSK Transmitter

The differential encoder block will be implemented in accordance with the definition of Subsection 2.3.3.1.1. Given the symbol sequences Ik and Qk, and the proviso that a normalized impulse sign of +1 will increase frequency, the pre-coder will provide interoperability with the FQPSK signals defined herein if code symbols are mapped to frequency impulses in accordance with Table 2-5 where ∆Φ is the phase change.

Table 2-5. SOQPSK Pre-Coding Table for IRIG-106 Compatibility

Map αK from IK

Ik

Qk−1

Ik−2

∆Φ

αk

Qk+1

−1

X*

−1

0

0

−1

+1

X*

+1

0

0

+1

−1

−1

+1 −π/2 −1

−1

−1

+1

+1 +π/2 +1

−1

+1

−1

−1 +π/2 +1

+1

+1

+1

−1 −π/2 −1

+1

* Note: Does not matter if “X” is a +1 or a −1

Map αK+1 from QK+1

Ik

Qk−1

∆Φ

αk+1

X*

−1

0

0

X*

+1

0

0

−1

+1 +π/2 +1

+1

+1 −π/2 −1

−1

−1 −π/2 −1

+1

−1 +π/2 +1

2.3.3.3 Characteristics of Advanced Range Telemetry Continuous Phase Modulation The ARTM CPM is a quaternary signaling scheme in which the instantaneous frequency
of the modulated signal is a function of the source data stream. The frequency pulses are shaped for spectral containment purposes. The modulation index alternates at the symbol rate between two values to improve the likelihood that the transmitted data is faithfully recovered. Although the following description is in terms of carrier frequency, other representations and generation methods exist that are equivalent. A block diagram of a conceptual ARTM CPM modulator is illustrated in Figure 2-4. Source bits are presented to the modulator and are mapped into impulses that are applied to a filter with an impulse response g(t). The resulting waveform f(t) is proportional to the instantaneous frequency of the desired modulator output. This signal can be used to frequency modulate a carrier to produce an RF signal representation.

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Figure 2-4. Conceptual CPM Modulator

Variables and function definitions in Figure 2-4 are as follows.

• a(iT/2) = ith bit of binary source data, either a 0 or 1.

• The frequency pulse shape for ARTM CPM is a three-symbol-long raised cosine pulse defined by the following equation for 0 ≤ t ≤3T,

g (t )

=

1 6T

1 −

cos 

2π t 3T



(2-11)

• T = Symbol period equal to 2/(bit rate in bits/second).
• α(iT) = ith impulse with area equal to either a +3, +1, −1, or −3 determined by Table 2-6. Note that an impulse is generated for each dibit pair (at the symbol rate).

Table 2-6. Dibit to Impulse Area Mapping

Input Dibit [a(i) a(i+1)]
1 1 1 0 0 1 0 0

Impulse Area
+3 +1 −1 −3

• f(t, α) = frequency filter output equal to the following equation.

+∞
π hi ∑α (iT )g(t − iT ) i=−∞

(2-12)

• h = modulation index; h alternates between h1 and h2 where h1 = 4/16, h2 = 5/16.
For more information on the ARTM CPM waveform, please refer to 0 and to Geoghegan’s paper.14

2.3.3.4 Data Randomization The data input to the transmitter shall be randomized using either an encryptor that
provides randomization or an Inter-Range Instrumentation Group (IRIG) 15-bit randomizer as

14 Mark Geoghegan. “Description and Performance Results for the Multi-h CPM Tier II Waveform.” Paper presented at the 36th International Telemetering Conference, San Diego, CA, October 2000.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
described in Chapter 6 and Annex A.2. The purpose of the randomizer is to prevent degenerative data patterns from degrading data quality. 2.3.3.5 Bit Rate
The bit rate range for FQPSK-B, FQPSK-JR, and SOQPSK-TG shall be between 1 megabit per second (Mbps) and 20 Mbps. The bit rate range for ARTM CPM shall be between 5 Mbps and 20 Mbps. 2.3.3.6 Transmitter Phase Noise
The sum of all discrete spurious spectral components (single-sideband) shall be less than −36 dBc. The continuous single-sideband phase noise power spectral density (PSD) shall be below the curve shown in Figure 2-5. The maximum frequency for the curve is one-fourth of the bit rate. For bit rates greater than 4 Mbps, the phase noise PSD shall be less than −100 dBc/hertz (Hz) between 1 MHz and one-fourth of the bit rate.
Figure 2-5. Continuous Single-Sideband Phase Noise Power Spectral Density
2.3.3.7 Modulation Polarity An increasing voltage at the input of an FM transmitter shall cause an increase in output
carrier frequency. An increase in voltage at the input of a PM transmitter shall cause an advancement in the phase of the output carrier. An increase in voltage at the input of an amplitude modulation (AM) transmitter shall cause an increase in the output voltage of the output carrier.
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2.3.4 Spurious Emission and Interference Limits Spurious15 emissions from the transmitter case, through input and power leads, and at the
transmitter RF output and antenna-radiated spurious emissions are to be within required limits shown in Military Standard (MIL-STD)-461.16 Other applicable standards and specifications
may be used in place of MIL-STD-461 if necessary.

2.3.4.1 Transmitter-Antenna System Emissions Emissions from the antenna are of primary importance. For example, a tuned antenna
may or may not attenuate spurious frequency products produced by the transmitter, and an antenna or multi-transmitter system may generate spurious outputs when a pure signal is fed to its input. The transmitting pattern of such spurious frequencies is generally different from the pattern at the desired frequency. Spurious outputs in the transmitter output line shall be limited to −25 dBm. Antenna-radiated spurious outputs shall be no greater than 320 µV/meter at 30 meters in any direction.

WARNING

Spurious levels of −25 dBm may severely degrade performance of sensitive receivers whose antennas are located in close proximity to the telemetry transmitting antenna. Therefore, lower spurious levels may be required in certain frequency ranges, such as near Global Positioning System frequencies.

2.3.4.2 Conducted and Radiated Interference Interference (and the RF output itself) radiated from the transmitter or fed back into the
transmitter power, signal, or control leads could interfere with the normal operation of the transmitter or the antenna system to which the transmitter is connected. All signals conducted by the transmitter's leads (other than the RF output cable) in the range of 150 kilohertz (kHz) to 50 MHz and all radiated fields in the range of 150 kHz to 10 gigahertz (GHz) (or other frequency ranges as specified) must be within the limits of the applicable standards or specifications.

2.3.5 Operational Flexibility
Each transmitter shall be capable of operating at all frequencies within its allocated band without design modification.17

2.3.6 Modulated Transmitter Bandwidth18 Telemetry applications covered by this standard shall use 99-percent power bandwidth to
define occupied bandwidth and −25 dBm bandwidth as the primary measure of spectral efficiency. The −25 dBm bandwidth is the minimum bandwidth that contains all spectral components that are −25 dBm or larger. A power level of −25 dBm is exactly equivalent to an attenuation of the transmitter power by 55 + 10×log(P) dB where P is the transmitter power expressed in watts. The spectra are assumed symmetrical about the transmitter’s center

15 Any unwanted signal or emission is spurious whether or not it is related to the transmitter frequency (harmonic). 16 Department of Defense. “Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment.” MIL-STD-461. 11 December 2015. May be superseded by update. Retrieved 23 March 2017. Available at http://quicksearch.dla.mil/qsDocDetails.aspx?ident_number=35789. 17 The intent is that fixed-frequency transmitters can be used at different frequencies by changing crystals or other components. All applicable performance requirements will be met after component change. 18 These bandwidths are measured using a spectrum analyzer with the following settings: 30-kHz resolution bandwidth, 300-Hz video bandwidth, and no max hold detector or averaging.

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frequency unless specified otherwise. All spectral components larger than −(55 + 10×log(P)) dBc at the transmitter output must be within the spectral mask calculated using the following equation:

M ( f ) = K + 90 log R −100 log f − fc ; f − fc ≥ R
m

(2-13)

where M(f) = power relative to P (i.e., units of dBc) at frequency f (MHz) K = −20 for analog signals = −28 for binary signals = −61 for FQPSK-B, FQPSK-JR, SOQPSK-TG = −73 for ARTM CPM fc = transmitter center frequency (MHz) R = bit rate (Mbps) for digital signals or (Δf + fmax) (MHz) for analog FM signals m = number of states in modulating signal; m = 2 for binary signals m = 4 for quaternary signals and analog signals
∆ f = peak deviation
fmax = maximum modulation frequency
Note that the mask in this standard is different than the masks contained in earlier versions of the Telemetry Standards. Equation 2-13 does not apply to spectral components separated from the center frequency by less than R/m. The −25 dBm bandwidth is not required to be narrower than 1 MHz. Binary signals include all modulation signals with two states while quaternary signals include all modulation signals with four states (quadrature phase shift keying [QPSK] and FQPSK-B are two examples of four-state signals). Section A.6 contains additional discussion and examples of this spectral mask.

2.3.7 Valid Center Frequencies Near Telemetry Band Edges The telemetry bands, as specified, start and stop at discrete frequencies. Telemetry
transmitters transmitting PCM/FM or SOQPSK-TG/FQPSK-B/FQPSK-JR or ARTM CPM, even with optimal filtering, do not have discrete start and stop frequencies. In order to determine a valid carrier frequency, the transmitter power, modulation scheme, and data rate must be known. The distance, in frequency, from the point in which the spectral masks, as described in Subsection 2.3.6, intersect the absolute value of −25 dBm equals the amount in which the transmitter carrier frequency must be from the band edge frequency. Subsection A.12 contains additional discussion and examples of center frequency determination when operating near telemetry band edges.

2.4 Telemetry Receiver Systems As a minimum, receiver systems shall have the following characteristics.

2.4.1 Spurious Emissions The RF energy radiated from the receiver itself or fed back into the power supply, and/or
the RF input, output, and control leads in the range from 150 kHz to 10 GHz shall be within the limits specified in MIL-STD-461. The receiver shall be tested in accordance with MIL-STD-461

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or RCC Document 118, Volume II.19 Other applicable standards and specifications may be used in place of MIL-STD-461, if necessary.

2.4.2 Frequency Tolerance The accuracy of all local oscillators within the receiver shall be such that the conversion
accuracy at each stage and overall is within ±0.001 percent of the indicated tuned frequency under all operating conditions for which the receiver is specified.

2.4.3 Receiver Phase Noise The sum of all discrete spurious spectral components (single-sideband) shall be less than
−39 dBc. The continuous single-sideband phase noise PSD shall be 3 dB below the curve shown in Figure 2-5. The maximum frequency for the curve in Figure 2-5 is one-fourth of the bit rate. For bit rates greater than 4 Mbps, the phase noise PSD shall be less than −103 dBc/Hz between 1 MHz and one-fourth of the bit rate.

2.4.4 Spurious Responses Rejection of any frequency other than the one to which the receiver is tuned shall be a
minimum of 60 dB referenced to the desired signal over the range 150 kHz to 10 GHz.

2.4.5 Operational Flexibility All ground-based receivers shall be capable of operating over the entire band for which
they are designed. External down-converters may be either intended for the entire band or a small portion but capable of retuning anywhere in the band without modification.

2.4.6 Intermediate Frequency Bandwidths
The standard receiver intermediate frequency (IF) bandwidths are shown in Table 2-7.
These bandwidths are separate from and should not be confused with post-detection low-pass filtering that receivers provide.20 The ratio of the receiver’s −60 dB bandwidth to the −3 dB bandwidth shall be less than 3 for new receiver designs.

Table 2-7. Standard Receiver Intermediate Frequency Bandwidths

300 kHz 500 kHz 750 kHz 1000 kHz

1.5 MHz 2.4 MHz 3.3 MHz 4.0 MHz

6 MHz 10 MHz 15 MHz 20 MHz

1. For data receivers, the IF bandwidth should typically be selected so that 90 to 99 percent of the transmitted spectrum is within the receiver 3 dB bandwidth. In most cases, the optimum IF bandwidth will be narrower than the 99 percent power bandwidth.

19 Range Commanders Council. Test Methods for Telemetry Systems and Subsystems Volume 2. RCC 118-12. May be superseded by update. Retrieved 4 June 2015. Available at http://www.wsmr.army.mil/RCCsite/Documents/118-12_Vol_2-Test_Methods_for_Telemetry_RF_Subsystems/. 20 In most instances, the output low-pass filter should not be used to “clean up” the receiver output prior to use with demultiplexing equipment.
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2. Bandwidths are expressed at the points where response is 3 dB below the response at the design center frequency, assuming that passband ripple is minimal, which may not be the case. The 3-dB bandwidth is chosen because it closely matches the noise bandwidth of a “brick-wall” filter of the same bandwidth. The “optimum” bandwidth for a specific application may be other than that stated here. Ideal IF filter response is symmetrical about its center frequency; in practice, this may not be the case.
3. Not all bandwidths are available on all receivers or at all test ranges. Additional receiver bandwidths may be available at some test ranges, especially if the range has receivers with digital IF filtering
2.4.7 C-band Downconversion For telemetry receive systems employing C-band downconversion, the following
mapping of C-band RF to C-band IF frequencies is recommended for the lower C and middle C bands. This downconversion scheme utilizes a high-side local oscillator frequency of 5550 MHz to minimize the potential of mixing products interfering with received telemetry signals. Additionally, using a standardized approach fosters interoperability between manufacturers of telemetry antenna systems employing downconversion and manufacturers of telemetry receivers with C-IF tuners.
No recommendation will be made at this point for the downconversion of the upper C band (5925-6700 MHz).
Examples:
C-IF Frequency = (5550 MHz − C-RF Frequency) 1150 MHz = (5550 MHz − 4400 MHz) 610 MHz = (5550 MHz − 4940 MHz) 459 MHz = (5550 MHz − 5091 MHz) 400 MHz = (5550 MHz − 5150 MHz)
2.5 Codes for Telemetry Systems
2.5.1 Low-Density Parity-Check Code Forward error correction (FEC) is a way of adding additional information to a transmitted
bit stream in order to decrease the required signal-to-noise ratio to the receiver for a given bit error rate (BER). Low-density parity-check (LDPC) code is a block code, meaning that a block of information bits has parity added to them in order to correct for errors in the information bits. The term “low-density” stems from the parity check matrix containing mostly 0’s and relatively few 1’s. This specific LDPC variant comes from the satellite link community and is identical to the Accumulate-Repeat-4-Jagged-Accumulate code described by the Consultative Committee for Space Data Systems (CCSDS) standard 131.1-O-2-S.1,21 which describes nine different LDPC codes with different coding rates (rate 1/2, 2/3, 4/5) and information block sizes (1024, 4096, 16384). In the trade between the transmission channel characteristics, bandwidth efficiency,
21 Consultative Committee for Space Data Systems. Low Density Parity Check Codes for Use in Near-Earth and Deep Space Applications. Standard CCSDS 131.1-O-2-S. September 2007. Rescinded. Retrieved 30 June 2015. Available at http://public.ccsds.org/publications/archive/131x1o2e2s.pdf.
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coding gain, and block size all three rates and block sizes 1024 and 4096 are considered in this standard. Additional information on this LDPC code is contained in Appendix 2-D.
2.5.2 Space-Time Code As the name suggests, this code uses space diversity and time diversity to overcome the
two-antenna problem, which is characterized by large variances in the antenna gain pattern from a test article caused by transmitting the same telemetry signal time through two transmit antennas. These signals are typically delayed in time and have differing amplitudes. The spacetime code (STC) in this standard applies to only SOQPSK-TG modulation. The input bit stream is space-time coded, resulting in two parallel bit streams that then have a pilot sequence added to each at fixed bit intervals (or blocks). These encoded/pilot-added streams are then individually modulated through phase-locked transmitters to a carrier using SOQPSK-TG modulation, power amplified, then connected to a top and bottom antenna. The job of estimating frequency offset, delays, gains, and phase shifts due to the transmission channel then space-time decode the signal is done with the STC receiver. Additional information on the STC is contained in Appendix 2-E.
2.6 Randomization Methods for Telemetry Systems
2.6.1 Introduction The following randomization and de-randomization methods are recommended for
wireless serial streaming telemetry data links. The choice of randomization method used should be based on whether or not a self-synchronizing randomizer is required for the application.
2.6.2 Randomizer Types
2.6.2.1 Self-Synchronizing Randomizers Self-synchronizing randomizers, such as the traditional IRIG randomizer described in
Annex A.2, work best when there are no known identifiers in the bit stream to aid in synchronizing the de-randomizer. This type of de-randomizer has the characteristic of creating additional bit errors when a bit error is received at the de-randomizer input. For this randomizer a single bit error at the input will create an additional two bit errors in the output stream. This BER extension will cause a degradation in detection efficiency of the link of approximately 0.5 dB.
2.6.2.2 Non-Self-Synchronizing Randomizers Non-self-synchronizing randomizers, such as the CCSDS randomizer described in
Appendix 2-D, do not create additional bit errors when a bit error is received at the derandomizer input. Therefore there is no extension of BER; however, these types of randomizers need to be synchronized with the incoming bit stream. This is usually accomplished through the use of pilot bits or synchronization markers in the data stream to aid in synchronization. Performance of this type of randomizer will exceed that of a self-synchronizing randomizer lending itself as a better choice for coded links or links requiring data-aided synchronization.
2.6.3 Randomizer Application As defined in Appendix 2-D, CCSDS randomization as defined in should be used for
coded links such as LDPC links or links exhibiting a block structure with synchronization markers.
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Traditional IRIG randomization as defined in Annex A.2 should be used for nonencrypted links that are absent of synchronization markers or do not contain markers of any type. Encrypted telemetry links do not require randomization.

2.7 Data Quality Metrics and Data Quality Encapsulation
A reliable metric for estimating data quality can be very useful when controlling telemetry data processing equipment, such as Best Source Selectors, that require an understanding of received data quality in order to operate effectively. To accomplish this, a standardized method for estimating bit error probability (BEP) is needed. In addition to the metric, a standardized method for transporting the metric with the associated data is required. Appendix 2-G provides a standard for a Data Quality Metric (DQM), determined in the telemetry receiver demodulator, and a standard for Data Quality Encapsulation (DQE) allowing for transport of the received telemetry data and associated DQM.

2.8 Interference Protection Criteria for Aeronautical Mobile Telemetry Systems

Aeronautical mobile telemetry (AMT) ground stations use very high gain directional antenna systems that are sensitive to interference from other RF communication systems. Without appropriate interference protection, these systems could be severely impacted or even rendered useless for mission support. To prevent this from happening, appropriate interference protection criteria (IPC) are needed.

Table 2-8 lists the acceptable power flux density (PFD) levels for interference in each telemetry band. These levels are based on the well-established and accepted IPC contained in International Telecommunications Union Radio Service (ITU-R) Recommendation M.145922 (Rec M.1459). These IPCs provide AMT protection for aggregate interference from satellites
and terrestrial emitters as a function of the angle of arrival α of the interfering signal(s) at or above the horizon derived using the methodology given in Annex A of Rec M.1459.

Table 2-8. Interference Protection Criteria by Band and Angle of Arrival

−181.0 −193.0 + 20 log α −213.3 + 35.6 log α −150.0
−181.0 −190.878 + 21.948 log α −185.722 + 18.286 log α −153.7
−180.0

L band, from 1435 – 1535 MHz

dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz

for 0 ≤ α ≤ 4° for 4 < α ≤ 20° for 20 < α ≤ 60° for 60 < α ≤ 90°

Upper L band, from 1755 – 1855 MHz

dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz

for 0° ≤ α ≤ 3° for 3° < α ≤ 15° for 15° < α ≤ 60° for 60° < α ≤ 90°

Lower S band, from 2200 – 2290 MHz

dB(W/m2) in 4 kHz for 0° ≤ α ≤ 2°

22 International Telecommunication Union. “Protection criteria for telemetry systems in the aeronautical mobile service…” ITU-R Recommendation M.1459. May 2000. May be superseded by update. Available at https://www.itu.int/rec/R-REC-M.1459-0-200005-I/en.
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Table 2-8. Interference Protection Criteria by Band and Angle of Arrival

−186.613 + 21.206 log α −161

dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz

for 2° < α ≤ 15° for 15° < α ≤ 90°

Upper S band, from 2310 – 2390 MHz

−180.0 −187.5 + 23.66 log α −162

dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz

for 0° ≤ α ≤ 2° for 2° < α ≤ 11.5° for 11.5° < α ≤ 90°

Lower C band, from 4400 – 4940 MHz

−178.0 −180.333 + 2.333 α −171.0

dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz

for 0° ≤ α ≤ 1° for 1° < α ≤ 4° for 4° < α ≤ 90°

Middle C band, from 5091 – 5150 MHz

−178.0 −180.0 + 2.0 α −174.0

dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz

for 0° ≤ α ≤ 1° for 1° < α ≤ 3° for 3° < α ≤ 90°

Upper C band, from 5925 – 6700 MHz

−178.0 −181.6 + 3.6 α −174.4

dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz dB(W/m2) in 4 kHz

for 0° ≤ α ≤ 1° for 1° < α ≤ 2° for 2° < α ≤ 90°

Appendix 2-F provides additional explanation and example calculations to aid in understand the application of these IPCs for different interference scenarios.

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Frequency Considerations for Telemetry
A.1. Purpose This appendix was prepared with the cooperation and assistance of the Range
Commanders Council (RCC) Frequency Management Group. This appendix provides guidance to telemetry users for the most effective use of the telemetry bands. Coordination with the frequency managers of the applicable test ranges and operating areas is recommended before a specific frequency band is selected for a given application. Government users should coordinate with the appropriate Area Frequency Coordinator and commercial users should coordinate with the AFTRCC. A list of the points of contact can be found in the NTIA manual (NTIA 2015).
A.2. Scope This appendix is to be used as a guide by users of telemetry frequencies at Department of
Defense (DoD)-related test ranges and contractor facilities. The goal of frequency management is to encourage maximal use and minimal interference among telemetry users and between telemetry users and other users of the electromagnetic spectrum.
A.2.a. Definitions The following terminology is used in this appendix.
Allocation (of a Frequency Band). Entry of a frequency band into the Table of Frequency Allocations23 for use by one or more radio communication services or the radio astronomy service under specified conditions. Assignment (of a Radio Frequency or Radio Frequency Channel). Authorization given by an administration for a radio station to use an RF or RF channel under specified conditions. Authorization. Permission to use an RF or RF channel under specified conditions. Certification. The Military Communications - Electronics Board’s (MCEB) process of verifying that a proposed system complies with the appropriate rules, regulations, and technical standards. J/F 12 Number. The identification number assigned to a system by the MCEB after the Application for Equipment Frequency Allocation (DD Form 1494) is approved; for example, J/F 12/6309 (sometimes called the J-12 number). Resolution Bandwidth. The −3 dB bandwidth of the measurement device.
A.2.b. Modulation methods A.2.b(1) Traditional Modulation Methods
The traditional modulation methods for aeronautical telemetry are FM and PM. The PCM/FM method has been the most popular telemetry modulation since around 1970. The
23 The definitions of the radio services that can be operated within certain frequency bands contained in the radio regulations as agreed to by the member nations of the International Telecommunications Union. This table is maintained in the United States by the Federal Communications Commission and the NTIA.
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PCM/FM method could also be called filtered CPFSK. The RF signal is typically generated by filtering the baseband NRZ-L signal and then frequency modulating a VCO. The optimum peak deviation is 0.35 times the bit rate and a good choice for a premodulation filter is a multi-pole linear phase filter with bandwidth equal to 0.7 times the bit rate. Both FM and PM have a variety of desirable features but may not provide the required bandwidth efficiency, especially for higher bit rates.
A.2.b(2) Improved Bandwidth Efficiency When better bandwidth efficiency is required, the standard methods for digital signal
transmission are the FQPSK-B and FQPSK-JR, the SOQPSK-TG, and the ARTM CPM. Each of these methods offers constant, or nearly constant, envelope characteristics and is compatible with nonlinear amplifiers with minimal spectral regrowth and minimal degradation of detection efficiency. The first three methods (FQPSK-B, FQPSK-JR, and SOQPSK-TG) are interoperable and require the use of the differential encoder described in Subsection 2.3.3.1.1. Additional information on this differential encoder is contained in 0. All of these bandwidth-efficient modulation methods require the data to be randomized.
A.2.c. Other Notations
The following notations are used in this appendix. Other references may define these terms slightly differently.
a. B99% - Bandwidth containing 99% of the total power.
b. B-25dBm - Bandwidth containing all components larger than −25 dBm.
c. B-60dBc - Bandwidth containing all components larger than the power level that is 60 dB below the unmodulated carrier power.
d. dBc - Decibels relative to the power level of the unmodulated carrier.
e. fc - Assigned center frequency.
A.3. Authorization to Use a Telemetry System
All RF emitting devices must have approval to operate in the US&P via a frequency assignment unless granted an exemption by the national authority. The NTIA is the President’s designated national authority and spectrum manager. The NTIA manages and controls the use of RF spectrum by federal agencies in US&P territory. Obtaining a frequency assignment involves the two-step process of obtaining an RF spectrum support certification of major RF systems design, followed by an operational frequency assignment to the RF system user. These steps are discussed below.
A.3.a. RF Spectrum Support Certification
All major RF systems used by federal agencies must be submitted to the NTIA, via the Interdepartment Radio Advisory Committee, for system review and spectrum support certification prior to committing funds for acquisition/procurement. During the system review process, compliance with applicable RF standards, RF allocation tables, rules, and regulations is checked. For DoD agencies and for support of DoD contracts, this is accomplished via the submission of a DD Form 1494 to the MCEB. Noncompliance with standards, the tables, rules, or regulations can result in denial of support, limited support, or support on an unprotected non-
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priority basis. All RF users must obtain frequency assignments for any RF system (even if not considered major). This assignment is accomplished by submission of frequency use proposals through the appropriate frequency management offices. Frequency assignments may not be granted for major systems that have not obtained spectrum support certification.
A.3.a(1) Frequency Allocation As stated before, telemetry systems must normally operate within the frequency bands
designated for their use in the Table of Frequency Allocations. With sufficient justification, use of other bands may at times be permitted, but the certification process is much more difficult, and the outcome is uncertain. Even if certification is granted on a noninterference basis to other users, the frequency manager is often unable to grant assignments because of local users who will get interference.
a. Telemetry Bands Air and space-to-ground telemetering is allocated in the ultra-high frequency (UHF)
bands 1435 to 1535, 2200 to 2290, and 2310 to 2390 MHz (commonly known as the lower Lband, the lower S-band, and the upper S-band) and in the super-high frequency (SHF) bands 4400 to 4940 and 5091 to 5150 MHz (commonly known as lower C-band and middle C-band). Other mobile bands, such as 1755-1850 MHz, can also be used at many test ranges. Since these other bands are not considered a standard telemetry band per this document, potential users must coordinate, in advance, with the individual range(s) and ensure use of this band can be supported at the subject range(s) and that their technical requirements will be met.
b. Very High Frequency Telemetry The very-high frequency (VHF) band, 216-265 MHz, was used for telemetry operations
in the past. Telemetry bands were moved to the UHF bands as of 1 January 1970 to prevent interference to critical government land mobile and military tactical communications. Telemetry operation in this band is strongly discouraged and is considered only on an exceptional case-bycase basis.
A.3.a(2) Technical Standards The MCEB and the NTIA review proposed telemetry systems for compliance with
applicable technical standards. For the UHF and SHF telemetry bands, the current revisions of the following standards are considered applicable:
a. RCC Document IRIG 106, Telemetry Standards;
b. MIL-STD-461;
c. NTIA Manual of Regulations and Procedures for Federal Radio Frequency Management.
Applications for certification are also thoroughly checked in many other ways, including necessary and occupied bandwidths, modulation characteristics, reasonableness of output power, correlation between output power and amplifier type, and antenna type and characteristics. The associated receiver normally must be specified or referenced. The characteristics of the receiver are also verified.
A.3.b. Frequency Authorization
Spectrum certification of a telemetry system verifies that the system meets the technical requirements for successful operation in the electromagnetic environment; however, a user is not permitted to radiate with the telemetry system before requesting and receiving a specific
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frequency assignment. The assignment process considers when, where, and how the user plans to radiate. Use of the assignments is tightly scheduled by and among the individual ranges to make the most efficient use of the limited telemetry RF spectrum and to ensure that one user does not interfere with other users.
A.4. Frequency Usage Guidance Frequency usage is controlled by scheduling in the areas where the tests will be
conducted. Figure A-1 displays the four modulation methods addressed in this section. The following recommendations are based on good engineering practice for such usage and it is assumed that the occupied bandwidth fits within the telemetry band in all cases.

Figure A-1. Spectra of 10-Mbps PCM/FM, ARTM CPM, FQPSK-JR, SOQPSK-TG Signals

A.4.a. Minimum Frequency Separation The minimum required frequency separation can be calculated using the formula:

∆F 0 = as * Rs + ai * Ri

(A-1)

where

ΔF0 = the minimum required center frequency separation in MHz; Rs = bit rate of desired signal in Mbps; Ri = bit rate of interfering signal in Mbps; as is determined by the desired signal type and receiving equipment (Table A-1).

Table A-1. Coefficients for Minimum Frequency Separation Calculation

Modulation Type

as

ai

NRZ PCM/FM

1.0* for receivers with resistor-inductor-capacitor (RLC) 1.2

final IF filters

0.7 for receivers with surface acoustic wave (SAW) or

digital IF filters

0.5 with multi-symbol detectors (or equivalent devices)

FQPSK-B, FQPSK-JR, 0.45

0.65

SOQPSK-TG

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ARTM CPM

0.35

0.5

*The minimum frequency separation for typical receivers with RLC final IF filters and NRZ-L

PCM/FM signals is the larger of 1.5 times the actual IF −3 dB bandwidth and the value

calculated using the equation above.

The minimum spacing needs to be calculated for signal 1 as the desired signal and signal 2 as the interferer and vice versa. Note that the values for ai match the −57 dBc points for the four modulation methods shown in Figure A-1 quite closely. It is not surprising that the required frequency spacing from the interferer is directly related to the power spectrum of the interfering signal. The values for as are a function of the effective detection filter bandwidths and the cochannel interference resistance of the desired signal modulation method and detector. The values for as and ai are slightly conservative for most cases and assume the receiver being used does not have spurious responses that cause additional interference. This section was completely rewritten from previous editions of the Telemetry Standards because addition of new modulation methods and new receiving equipment rendered the old method obsolete. The values of as and ai were determined empirically from the results of extensive adjacent channel interference testing. The main assumptions are as follows.

a. The NRZ PCM/FM signals are assumed to be premodulation filtered with a multi-pole filter with −3 dB point of 0.7 times the bit rate and the peak deviation is assumed to be approximately 0.35 times the bit rate.

b. The receiver IF filter is assumed to be no wider than 1.5 times the bit rate and provides at least 6 dB of attenuation of the interfering signal.

c. The interfering signal is assumed to be no more than 20 dB stronger than the desired signal.

d. The receiver is assumed to be operating in linear mode; no significant intermodulation products or spurious responses are present.

Examples are shown below.

5-Mbps PCM/FM and 0.8-Mbps PCM/FM using a receiver with 6-MHz IF bandwidth for the 5-Mbps signal (this receiver has RLC IF filters)

1.0*5 + 1.2*0.8 = 5.96 MHz

1.0*0.8 + 1.2*5 = 6.8 MHz

1.5*6= 9.0 MHz

The largest value is 9 MHz and the frequencies are assigned in 1-MHz steps, so the minimum spacing is 9 MHz.

5-Mbps PCM/FM and 5-Mbps PCM/FM using a receiver with 6-MHz IF bandwidth for the 5-Mbps signals (these receivers have RLC IF filters; see Figure A-2)

1.0*5 + 1.2*5 = 11 MHz

1.5*6= 9.0 MHz

The larger value is 11 MHz and the frequencies are assigned in 1-MHz steps, so the minimum spacing is 11 MHz.

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Figure A-2. 5 Mbps PCM/FM Signals with 11 MHz Center Frequency Separation
5-Mbps PCM/FM and 5-Mbps PCM/FM using a receiver with 6-MHz IF bandwidth for the 5-Mbps signal (this receiver has RLC IF filters but a multi-symbol detector is used) 0.5*5 + 1.2*5 = 8.5 MHz The frequencies are assigned in 1-MHz steps, so the minimum spacing is 9 MHz.

5-Mbps PCM/FM and 5-Mbps SOQPSK-TG using a receiver with 6-MHz IF bandwidth for the 5-Mbps signals (this receiver has RLC IF filters but a multi-symbol detector is used)

0.5*5 + 0.65*5 = 5.75 MHz

0.45*5 + 1.2*5 = 8.25 MHz

The largest value is 8.25 MHz and the frequencies are assigned in 1-MHz steps, so the minimum spacing is 9 MHz.

5-Mbps FQPSK-B and 5-Mbps ARTM CPM using a receiver with 6-MHz IF bandwidth for the 5-Mbps signals

0.45*5 + 0.5*5 = 4.75 MHz

0.35*5 + 0.7*5 = 5.25 MHz

The largest value is 5.25 MHz and the frequencies are assigned in 1-MHz steps, so the minimum spacing is 6 MHz.

10-Mbps ARTM CPM and 10-Mbps ARTM CPM (see Figure A-3) 0.35*10 + 0.5*10 = 8.5 MHz The frequencies are assigned in 1-MHz steps, so the minimum spacing is 9 MHz.

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Figure A-3. 10 Mbps ARTM CPM Signals with 9 MHz Center Frequency Separation
In some cases it may be desirable to set aside a bandwidth for each signal independent of other signals. If one uses a bandwidth factor of 2*ai for each signal, then one gets a separation of ΔF0 = ai*Rs + ai*Ri and one gets a more conservative (wider) separation than one would using ΔF0 = as*Rs + ai*Ri because the value of ai is bigger than the value of as for all of these modulation methods. One problem with this approach is that it does not include receiver or detector characteristics and therefore the calculated frequency separations are often different from those calculated using the formula in Subsection A.4.a.
Examples of frequency separation are shown below. 5-Mbps PCM/FM and 0.8-Mbps PCM/FM using a receiver with 6-MHz IF bandwidth for the 5-Mbps signal (this receiver has RLC IF filters) 1.2*5 + 1.2*0.8 = 6.96 MHz The frequencies are assigned in 1-MHz steps, so the minimum spacing is 7 MHz.
5-Mbps PCM/FM and 5-Mbps PCM/FM using a receiver with 6-MHz IF bandwidth for the 5-Mbps signals (these receivers have RLC IF filters) 1.2*5 + 1.2*5 = 12 MHz The frequencies are assigned in 1-MHz steps, so the minimum spacing is 12 MHz.
5-Mbps PCM/FM and 5-Mbps PCM/FM using a receiver with 6-MHz IF bandwidth for the 5-Mbps signal (this receiver has RLC IF filters but a multi-symbol detector is used) 1.2*5 + 1.2*5 = 12 MHz The frequencies are assigned in 1-MHz steps, so the minimum spacing is 12 MHz.
5-Mbps PCM/FM and 5-Mbps SOQPSK-TG using a receiver with 6-MHz IF bandwidth for the 5-Mbps signals (this receiver has RLC IF filters but a multi-symbol detector is used) 1.2*5 + 0.65*5 = 9.25 MHz
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The frequencies are assigned in 1-MHz steps, so the minimum spacing is 10 MHz.
5-Mbps FQPSK-B and 5-Mbps ARTM CPM using a receiver with 6-MHz IF bandwidth for the 5-Mbps signals 0.7*5 + 0.5*5 = 6 MHz The frequencies are assigned in 1-MHz steps, so the minimum spacing is 6 MHz.
10-Mbps ARTM CPM and 10-Mbps ARTM CPM 0.5*10 + 0.5*10 = 10 MHz The frequencies are assigned in 1-MHz steps, so the minimum spacing is 10 MHz.
A.4.b. Geographical Separation Geographical separation can be used to further reduce the probability of interference from
adjacent signals.
A.4.c. Multicarrier Operation If two transmitters are operated simultaneously and sent or received through the same
antenna system, interference due to intermodulation is likely at (2f1 − f2) and (2f2 − f1). Between three transmitters, the two-frequency possibilities exist, but intermodulation products may exist as well at (f1 + f2 − f3), (f1 + f3 − f2), and (f2 + f3 − f1), where f1, f2, and f3 represent the output frequencies of the transmitters. Intermodulation products can arise from nonlinearities in the transmitter output circuitry that cause mixing products between a transmitter output signal and the fundamental signal coming from nearby transmitters. Intermodulation products also can arise from nonlinearities in the antenna systems. The generation of intermodulation products is inevitable, but the effects are generally of concern only when such products exceed −25 dBm. The general rule for avoiding third-order intermodulation interference is that in any group of transmitter frequencies, the separation between any pair of frequencies should not be equal to the separation between any other pair of frequencies. Because individual signals have sidebands, it should be noted that intermodulation products have sidebands spectrally wider than the sidebands of the individual signals that caused them.
A.4.d. Transmitter Antenna System Emission Testing Radiated tests will be made in lieu of transmitter output tests only when the transmitter is
inaccessible. Radiated tests may still be required if the antenna is intended to be part of the filtering of spurious products from the transmitter or is suspected of generating spurious products by itself or in interaction with the transmitter and feed lines. These tests should be made with normal modulation.
A.5. Bandwidth The definitions of bandwidth in this section are universally applicable. The limits shown
here are applicable for telemetry operations in the telemetry bands specified in Chapter 2. For the purposes of telemetry signal spectral occupancy, the bandwidths used are B99% and
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

B-25dBm. A power level of −25 dBm is exactly equivalent to an attenuation of the transmitter power by 55 + 10×log(P) dB where P is the transmitter power expressed in watts. How bandwidth is actually measured and what the limits are, expressed in terms of that measuring system, are detailed in the following paragraphs.

A.5.a. Concept
The term “bandwidth” has an exact meaning in situations where an AM, doublesideband, or single-sideband signal is produced with a band-limited modulating signal. In systems employing FM or PM, or any modulation system where the modulating signal is not band limited, bandwidth is infinite with energy extending toward zero and infinite frequency falling off from the peak value in some exponential fashion. In this more general case, bandwidth is defined as the band of frequencies in which most of the signal’s energy is contained. The definition of “most” is imprecise. The following terms are applied to bandwidth.
A.5.a(1) Authorized Bandwidth For purposes of this document, the authorized bandwidth is the necessary bandwidth
required for transmission and reception of intelligence and does not include allowance for transmitter drift or Doppler shift.
A.5.a(2) Occupied Bandwidth The width of a frequency band such that below the lower and above the upper frequency
limits, the mean powers emitted are each equal to a specified percentage of the total mean power of a given emission. Unless otherwise specified by the ITU for the appropriate class of emission, the specified percentage shall be 0.5%. In this document occupied bandwidth and B99% are interchangeable.
A.5.a(3) Necessary Bandwidth for a Given Class of Emission For a given class of emission, the width of the frequency band that is just sufficient to
ensure the transmission of information at the rate and with the quality required under specified conditions. Note: the term “under specified conditions” does not include signal bandwidth required when operating with adjacent channel signals (i.e., potential interferers).
a. The NTIA Manual This manual states that “All reasonable effort shall be made in equipment design and
operation by Government agencies to maintain the occupied bandwidth of the emission of any authorized transmission as closely to the necessary bandwidth as is reasonably practicable.”
b. Necessary Bandwidth (DD Form 1494) The necessary bandwidth is part of the emission designator on the DD Form 1494. For
telemetry purposes, the necessary bandwidth can be calculated using the equations shown in Table A-2. Equations for these and other modulation methods are contained in Annex J of the NTIA Manual.

Table A-2. B99% for Various Digital Modulation Methods

Description NRZ PCM/FM, premod filter BW=0.7R, ∆f=0.35R NRZ PCM/FM, no premod filter, ∆f=0.25R NRZ PCM/FM, no premod filter, ∆f=0.35R

B99% 1.16 R 1.18 R 1.78 R

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

NRZ PCM/FM, no premod filter, ∆f=0.40R NRZ PCM/FM, premod filter BW=0.7R, ∆f=0.40R Minimum shift keying (MSK), no filter FQPSK-B, FQPSK-JR or SOQPSK-TG ARTM CPM

1.93 R 1.57 R 1.18 R 0.78 R 0.56 R

Filtered NRZ PCM/FM. Bn = 1.16*bit rate with h=0.7 and premodulation filter bandwidth = 0.7 times bit rate. Example: PCM/FM modulation used to send 5 Mbps using FM with 2 signaling states and 1.75 MHz peak deviation; bit rate=5*106; necessary bandwidth (Bn) = 5.8 MHz.
Constant envelope OQPSK; FQPSK-B, FQPSK-JR, or SOQPSK-TG. Bn = 0.78*bit rate. Example: SOPQSK-TG modulation used to send 5 Mbps using 4 signaling states; bit rate=5*106; Bn = 3.9 MHz.
ARTM CPM. Bn = 0.56*bit rate with h=4/16 and 5/16 on alternating symbols; digital modulation used to send 5 Mbps using FM with 4 signaling states and with alternating modulation index each symbol; bit rate=5*106; Bn = 2.8 MHz.
A.5.a(4) Received (or Receiver) Bandwidth The received bandwidth is usually the −3 dB bandwidth of the receiver IF section.
A.5.b. Bandwidth Estimation and Measurement
Various methods are used to estimate or measure the bandwidth of a signal that is not band limited. The bandwidth measurements are performed using a spectrum analyzer (or equivalent device) with the following settings: 30-kHz resolution bandwidth, 300-Hz video bandwidth, and no max hold detector or averaging. These settings are different than those in earlier versions of the Telemetry Standards. The settings were changed to get more consistent results across a variety of bit rates, modulation methods, and spectrum analyzers. The most common measurement and estimation methods are described in the following paragraphs.
A.5.b(1) B99% This bandwidth contains 99% of the total power. Typically, B99% is measured using a
spectrum analyzer or estimated using equations for the modulation type and bit rate used. If the two points that define the edges of the band are not symmetrical about the assigned center frequency, their actual frequencies and difference should be noted. The B99% edges of randomized NRZ (RNRZ) PCM/FM signals are shown in Figure A-4. Table A-2 presents B99% for several digital modulation methods as a function of the bit rate (R).

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
Figure A-4. RNRZ PCM/FM Signal A.5.b(2) B-25dBm
B-25dBm is the bandwidth containing all components larger than −25 dBm. A power level of −25 dBm is exactly equivalent to an attenuation of the transmitter power by 55 + 10×log(P) dB where P is the transmitter power expressed in watts. B-25dBm limits are shown in Figure A-4. B-25dBm is primarily a function of the modulation method, transmitter power, and bit rate. The transmitter design and construction techniques also strongly influence B-25dBm. With a bit rate of 5 Mbps and a transmitter power of 5 watts, the B-25dBm of an NRZ PCM/FM system with near optimum parameter settings is about 13.3 MHz, while B-25dBm of an equivalent FQPSK-B system is about 7.5 MHz, and B-25dBm of an equivalent ARTM CPM system is about 5.8 MHz. A.5.b(3) Scheduled Bandwidth
This bandwidth should be used by organizations responsible for either requesting or scheduling bandwidth required for telemetry signals. These signals are either packed tightly within existing telemetry bands, operating without adjacent signals, or are scheduled near telemetry band edges. Scheduled bandwidth should be calculated for these three cases in the following manner.
a. If the telemetry signal will be operating in the absence of adjacent signals, use the B99% (occupied bandwidth) calculations in Table A-2 to determine scheduled bandwidth.
b. If the telemetry signal will be operating in the in the presence of adjacent telemetry signals, use the minimum frequency separation calculations in Table A-1 to determine scheduled bandwidth.
c. If the telemetry signal will be operating near a telemetry band edge, use the calculations in Section A.12 to determine proper spacing from the band edge.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
A.5.c. Other Bandwidth Measurement Methods The methods discussed above are the standard methods for measuring the bandwidth of
telemetry signals. The following methods are also sometimes used to measure or to estimate the bandwidth of telemetry signals. a. Below Unmodulated Carrier
This method measures the power spectrum with respect to the unmodulated carrier power. To calibrate the measured spectrum on a spectrum analyzer, the unmodulated carrier power must be known. This power level is the 0-dB reference (commonly set to the top of the display). In AM systems, the carrier power never changes; in FM and PM systems, the carrier power is a function of the modulating signal. Therefore, a method to estimate the unmodulated carrier power is required if the modulation cannot be turned off. For most practical angle modulated systems, the total carrier power at the spectrum analyzer input can be found by setting the spectrum analyzer’s resolution and video bandwidths to their widest settings, setting the analyzer output to max hold, and allowing the analyzer to make several sweeps (see Figure A-3). The maximum value of this trace will be a good approximation of the unmodulated carrier level. Figure A-5 shows the spectrum of a 5-Mbps RNRZ PCM/FM signal measured using the standard spectrum analyzer settings discussed previously and the spectrum measured using 3-MHz resolution, video bandwidths, and max hold.
Figure A-5. Spectrum Analyzer Calibration of 0-dBc Level The peak of the spectrum measured with the latter conditions is very close to 0-dBc and can be used to estimate the unmodulated carrier power (0-dBc) in the presence of FM or PM. In practice, the 0-dBc calibration would be performed first, and the display settings would then be adjusted to use the peak of the curve as the reference level (0-dBc level) to calibrate the spectrum measured using the standard spectrum analyzer settings. With the spectrum analyzer set for a specific resolution bandwidth, video bandwidth, and detector type, the bandwidth is taken as the distance between the two points outside of which the spectrum is thereafter some number (say, 60 dB) below the unmodulated carrier power determined above. B-60dBc for the 5-Mbps signal shown in Figure A-5 is approximately 13 MHz.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

B-60dBc of an RNRZ PCM/FM signal with a peak deviation of 0.35R, a four-pole premodulation filter with −3 dB corner at 0.7R, and a bit rate greater than or equal to 1 Mbps can be approximated by the following equation:

(A-2)

where

B is in MHz; R is in Mbps.

Thus B-60dBc of a 5-Mbps RNRZ signal under these conditions would be approximately 12.85 MHz. B-60dBc will be greater if peak deviation is increased or the number of filter poles is decreased.

b. Below Peak This method is not recommended for measuring the bandwidth of telemetry signals. The
modulated peak method, the least accurate measurement method, measures between points where the spectrum is thereafter XX dB below the level of the highest point on the modulated spectrum. Figure A-6 shows the RF spectrum of a 400-kbps bi-phase (Biφ)-level PCM/PM signal with a peak deviation of 75° and a pre-modulation filter bandwidth of 800 kHz.

Figure A-6. Biφ PCM/PM Signal
The largest peak has a power level of −7 dBc. In comparison, the largest peak in Figure A-5 had a power level of −22 dBc. This 15-dB difference would skew a bandwidth comparison that used the peak level in the measured spectrum as a common reference point. In the absence of an unmodulated carrier to use for calibration, the below-peak measurement is often (erroneously) used and described as a below-unmodulated-carrier measurement. Using max hold exacerbates this effect still further. In all instances the bandwidth is overstated, but the amount varies. c. Carson’s Rule
Carson’s Rule is a method to estimate the bandwidth of an FM subcarrier system. Carson’s Rule states the following:
(A-3)
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
where B is the bandwidth; ∆f is the peak deviation of the carrier frequency; fmax is the highest frequency in the modulating signal.
Figure A-7 shows the spectrum that results when a 12-channel constant bandwidth multiplex with 6-dB/octave pre-emphasis frequency modulates an FM transmitter. B99% and the bandwidth calculated using Carson’s Rule are also shown. Carson’s Rule will estimate a value greater than B99% if little of the carrier deviation is due to high-frequency energy in the modulating signal.
Figure A-7. FM/AM Signal and Carson’s Rule A.5.d. Spectral Equations
The following equations can be used to calculate the RF spectra for several digital modulation methods with unfiltered waveforms.24, 25, 26 These equations can be modified to include the effects of filtering.27, 28 RNRZ PCM/FM (valid when D≠integer, D = 0.5 gives MSK spectrum)
(A-4)
24 I. Korn. Digital Communications, New York, Van Nostrand, 1985. 25 M. G. Pelchat. “The Autocorrelation Function and Power Spectrum of PCM/FM with Random Binary Modulating Waveforms,” IEEE Transactions, Vol. SET-10, No. 1, pp. 39-44, March 1964. 26 Tey, W. M. and T. Tjhung. “Characteristics of Manchester-Coded FSK,” IEEE Transactions on Communications, Vol. COM-27, pp. 209-216, January 1979. 27 Watt, A. D., V. J. Zurick, and R. M. Coon. “Reduction of Adjacent-Channel Interference Components from Frequency-Shift-Keyed Carriers,” IRE Transactions on Communication Systems, Vol. CS-6, pp. 39-47, December 1958. 28 E. L. Law. “RF Spectral Characteristics of Random PCM/FM and PSK Signals,” International Telemetering Conference Proceedings, pp. 71-80, 1991.
A-14

RNRZ PSK

Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

(A-5)

RNRZ QPSK and OQPSK

Random Biφ PCM/FM

S

(

f)=

2 BSA R

s

in2 (πX (πX )2

)

(A-6)

S ( f )=

  BSA  π D 4R  2  

sin π (X - D ) 4 π(X - D)
4

s

i

n  π

π(X + D 4
(X + D)

) 

2
   

+

  

4

 



D sin( πD ) 2
π( X 2 - D2 )
2

2   δ{(f  

−

fc)

−

n R}

(A-7)

Random Biφ PCM/PM

S ( f )=

BSA sin2( β R

)

sin4  πX 4
 πX 2

 

+ cos2(

β

)δ (f

−

fc) ,

β ≤π 2

4

(A-8)

where S(f) = power spectrum (dBc) at frequency f BSA = spectrum analyzer resolution bandwidth* R = bit rate D = 2∆f/R X = 2(f-fc)/R ∆f = peak deviation β = peak phase deviation in radians fc = carrier frequency δ = Dirac delta function N = 0, ±1, ±2, … Q = quantity related to narrow band spectral peaking when D≈1, 2, 3, ... Q ≈ 0.99 for BSA = 0.003 R, Q ≈ 0.9 for BSA = 0.03 R
*The spectrum analyzer resolution bandwidth term was added to the original equations.

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
A.5.e. Receiver Bandwidth Receiver predetection bandwidth is typically defined as the points where the response to
the carrier before demodulation is −3 dB from the center frequency response. The carrier bandwidth response of the receiver is, or is intended to be, symmetrical about the carrier in most instances. Figure A-8 shows the response of a typical older-generation telemetry receiver with RLC IF filters and a 1-MHz IF bandwidth selected. Outside the stated bandwidth, the response usually falls fairly rapidly, often 20 dB or more below the passband response at 1.5 to 2 times the passband response.
Figure A-8. Typical Receiver RLC IF Filter Response (−3 dB Bandwidth = 1 MHz)
Figure A-9 shows an overlay of an RLC IF filter and a SAW filter. Note that the SAW filter rolls off much more rapidly than the RLC filter. The rapid falloff outside the passband helps reduce interference from nearby channels and has minimal effect on data.
Figure A-9. RLC and SAW IF Filters A-16

Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
A.5.f. Receiver Noise Bandwidth
For the purpose of calculating noise in the receiver, the bandwidth must be integrated over the actual shape of the IF, which, in general, is not a square-sided function. Typically, the value used for noise power calculations is the −3 dB bandwidth of the receiver.
A.5.g. Symmetry
Many modulation methods produce a spectrum that is asymmetrical with respect to the carrier frequency. Exceptions include FM/FM systems, RNRZ PCM/FM systems, and randomized FQPSK, SOQPSK-TG, and ARTM CPM systems. The most extreme case of asymmetry is due to single-sideband transmission, which places the carrier frequency at one edge of the occupied spectrum. If the spectrum is not symmetrical about the band center, the bandwidth and the extent of asymmetry must be noted for frequency management purposes.
A.5.h. FM Transmitters (alternating current-coupled)
Alternating current-coupled FM transmitters should not be used to transmit NRZ signals unless the signals to be transmitted are randomized. This is because changes in the ratio of 1s to 0s will increase the occupied bandwidth and may degrade the BER. When alternating currentcoupled transmitters are used with RNRZ signals, it is recommended that the lower −3 dB frequency response of the transmitter be no greater than the bit rate divided by 4000. For example, if a randomized 1-Mbps NRZ signal is being transmitted, the lower −3 dB frequency response of the transmitter should be no larger than 250 Hz.
A.6. Spectral Occupancy Limits
Telemetry applications covered by this standard shall use B99% to define occupied bandwidth and B-25dBm as the primary measure of spectral efficiency. The spectra are assumed symmetrical about the center frequency unless otherwise specified. The primary reason for controlling the spectral occupancy is to control adjacent channel interference, thereby allowing more users to be packed into a given amount of frequency spectrum. The adjacent channel interference is determined by the spectra of the signals and the filter characteristics of the receiver.
A.6.a. Spectral Mask
One common method of describing the spectral occupancy limits is a spectral mask. The aeronautical telemetry spectral mask is described below. Note that the mask in this standard is different than the masks contained in the earlier versions of the Telemetry Standards. All spectral components larger than −[55 + 10×log(P)] dBc (i.e., larger than −25 dBm) at the transmitter output must be within the spectral mask calculated using the following equation:

where

M(f) = power (dBc) at frequency f (MHz) K = −20 for analog signals K = −28 for binary signals

(A-9)

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
K = −61 for FQPSK-B, FQPSK-JR, SOQPSK-TG K = −73 for ARTM CPM fc = transmitter center frequency (MHz) R = bit rate (Mbps) for digital signals or (∆f +fmax)(MHz) for analog FM signals M = number of states in modulating signal (m = 2 for binary signals, m = 4 for quaternary signals and analog signals)
∆ f = peak deviation
fmax = maximum modulation frequency
These bandwidths are measured using a spectrum analyzer with settings of 30-kHz resolution bandwidth, 300-Hz video bandwidth, and no max hold detector or averaging. Note that these settings are different than those listed in previous editions of the Telemetry Standards. The changes were made to get more consistent results with various bit rates and spectrum analyzers. The spectra measured with these settings give slightly larger power levels than with the previous settings; this is why the value of K was changed from −63 to −61 for FQPSK and SOQPSK signals. The power levels near center frequency should be approximately J−10log(R) dBc where J= −10 for ARTM CPM, −12 for FQPSK and SOQPSK-TG, and −15.5 for PCM/FM signals. For a bit rate of 5 Mbps, the level is approximately −17 dBc for ARTM CPM, −19 dBc for FQPSK, and −22.5 dBc for PCM/FM. If the power levels near center frequency are not within 3 dB of these values, then a measurement problem exists and the carrier power level (0 dBc) and spectrum analyzer settings should be verified.
B-25dBm is not required to be narrower than 1 MHz. The first term K in equation A-9 accounts for bandwidth differences between modulation methods. Equation A-9 can be rewritten as M(f) = K − 10logR − 100log|(f−fc)/R|. When equation A-9 is written this way, the 10logR term accounts for the increased spectral spreading and decreased power per unit bandwidth as the modulation rate increases. The last term forces the spectral mask to roll off at 30 dB/octave (100 dB/decade). Any error detection or error correction bits, which are added to the data stream, are counted as bits for the purposes of this spectral mask. The spectral masks are based on the power spectra of random real-world transmitter signals. For instance, the binary signal spectral mask is based on the power spectrum of a binary NRZ PCM/FM signal with peak deviation equal to 0.35 times the bit rate and a multipole premodulation filter with a −3 dB frequency equal to 0.7 times the bit rate (see Figure A-4). This peak deviation minimizes the BER with an optimum receiver bandwidth while also providing a compact RF spectrum. The premodulation filter attenuates the RF sidebands while only degrading the BER by the equivalent of a few tenths of a dB of RF power. Further decreasing of the premodulation filter bandwidth will only result in a slightly narrower RF spectrum, but the BER will increase dramatically. Increasing the premodulation filter bandwidth will result in a wider RF spectrum, and the BER will only be decreased slightly. The recommended premodulation filter for NRZ PCM/FM signals is a multipole linear phase filter with a −3 dB frequency equal to 0.7 times the bit rate. The unfiltered NRZ PCM/FM signal rolls off at 12 dB/octave so at least a three-pole filter (filters with four or more poles are recommended) is required to achieve the 30 dB/octave slope of the spectral mask. The spectral mask includes the effects of reasonable component variations (unitto-unit and temperature).
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
A.6.b. Spectral Mask Examples Figure A-10 and Figure A-11 show the binary spectral mask of equation A-9 and the RF
spectra of 5-Mbps RNRZ PCM/FM signals. The RF spectra were measured using a spectrum analyzer with 30-kHz resolution bandwidth, 300-Hz video bandwidth, and no max hold detector. The span of the frequency axis is 20 MHz. The transmitter power was 5 watts, and the peak deviation was 1750 kHz. The modulation signal for Figure A-10 was filtered with a 4-pole linear-phase filter with −3 dB frequency of 3500 kHz. All spectral components in Figure A-10 were contained within the spectral mask. The minimum value of the spectral mask was −62 dBc (equivalent to −25 dBm). The peak modulated signal power levels were about 22.5 dB below the unmodulated carrier level (−22.5 dBc). Figure A-11 shows the same signal with no premodulation filtering. The signal was not contained within the spectral mask when a premodulation filter was not used.
Figure A-10. Filtered 5-Mbps RNRZ PCM/FM Signal and Spectral Mask
Figure A-11. Unfiltered 5-Mbps RNRZ PCM/FM Signal and Spectral Mask
Figure A-12 shows the FQPSK/SOQPSK mask of equation A-9 and the RF spectrum of a 5-Mbps SOQPSK-TG signal. The transmitter power was assumed to be 5 watts in this example.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
The peak value of the SOQPSK-TG signal was about −19 dBc. Figure A-13 shows a typical 5Mbps ARTM CPM signal and its spectral mask. The peak value of the ARTM CPM signal was about −17 dBc.
Figure A-12. Typical 5-Mbps SOQPSK TG Signal and Spectral Mask

Figure A-13. Typical 5-Mbps ARTM CPM Signal and Spectral Mask

A.7. Technical Characteristics of Digital Modulation Methods
Table A-3 provides a summary of some of the technical characteristics of the modulation methods discussed in this summary.

Table A-3. Characteristics of Various Modulation Methods

Characteristic
Occupied Bandwidth Sensitivity (Eb/N0 for BEP=1e−5)

PCM/FM with single symbol detection
1.16 bit rate 11.8-15+ dB

PCM/FM with multi-symbol detection
1.16 bit rate 9.5 dB

FQPSK-B, FQPSK-JR, SOQPSK-TG
0.78 bit rate 11.8-12.2 dB

ARTM CPM
0.56 bit rate 12.5 dB

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

Synchronization time 100 to 10,000 250 bits

bits

Synchronization

3 to 4 dB

2 dB

threshold level (Eb/N0)

Phase noise

2

1

susceptibility*

Co-channel

2

1

interference

susceptibility*

* 1=Best, 2=Second Best, 3=Third Best, 4=Worst

5,000 to 30,000 bits
4.5 to 5 dB

30,000 to 150,000 bits
8.5 dB

3

4

3

4

A.8. FQPSK-B and FQPSK-JR Characteristics
Modulations of FQPSK-B and FQPSK-JR are a variation of OQPSK, which is described in most communications textbooks. A generic OQPSK (or quadrature or I & Q) modulator is shown in Figure A-14. In general, the odd bits are applied to one channel (say Q), and the even bits are applied to the I channel.

Figure A-14. OQPSK Modulator
If the values of I and Q are ±1, we get the diagram shown in Figure A-15. For example, if I=1 and Q=1 then the phase angle is 45 degrees {(I,Q) = (1, 1)}. A constant envelope modulation method, such as MSK, would follow the circle indicated by the small dots in Figure A-15 to go between the large dots. In general, band-limited QPSK and OQPSK signals are not constant envelope and would not follow the path indicated by the small dots but rather would have a significant amount of amplitude variation; however, FQPSK-B and FQPSK-JR are nearly constant envelope and essentially follow the path indicated by the small dots in Figure A-15.

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
Figure A-15. I and Q Constellation The typical implementation of FQPSK-B or FQPSK-JR involves the application of data and a bit rate clock to the baseband processor of the quadrature modulator. The data are differentially encoded and converted to I and Q signals as described in Chapter 2. The I and Q channels are then cross-correlated, and specialized wavelets are assembled that minimize the instantaneous variation of (I2(t) + Q2(t)). The FQPSK-B baseband wavelets are illustrated in Figure A-16.
Figure A-16. FQPSK Wavelet Eye Diagram The appropriate wavelet is assembled based on the current and immediate past states of I and Q, where Q is delayed by one-half symbol (one bit) with respect to I as shown in Figure A-17.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

Figure A-17. FQPSK-B I & Q Eye Diagrams (at Input to IQ Modulator)
A common method at looking at I-Q modulation signals is the use of a vector diagram. One method of generating a vector diagram is to use an oscilloscope that has an XY mode. The vector diagram is generated by applying the I signal to the X input and the Q signal to the Y input. A sample vector diagram of FQPSK-B at the input terminals of an I-Q modulator is illustrated in Figure A-18. Note that the vector diagram values are always within a few percent of being on a circle. Any amplitude variations may cause spectral spreading at the output of a nonlinear amplifier.
0 .5

Q

0

-0. 5 -0. 5

0

0 .5

I

Figure A-18. FQPSK-B Vector Diagram

Figure A-19 illustrates a nearly ideal FQPSK-JR spectrum (blue trace) and an FQPSK-JR spectrum with moderately large modulator errors (red trace). These spectra were measured at the output of a fully saturated RF nonlinear amplifier with a random pattern of 1s and 0s applied to the input. The bit rate for Figure A-19 was 5 Mbps. The peak of the spectrum was approximately −19 dBc. B99% of FQPSK-B is typically about 0.78 times the bit rate. Note that with a properly randomized data sequence and proper transmitter design, FQPSK-B does not have significant sidebands (blue trace).

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
Figure A-19. 5 Mbps FQPSK-JR Spectrum with Random Input Data and Small (Blue) and Large (Red) Modulator Errors
Figure A-20 illustrates an FQPSK-B transmitter output with all 0s as the input signal. With an all 0s input, the differential encoder, cross-correlator, and wavelet selector provide unity amplitude sine and cosine waves with a frequency equal to 0.25 times the bit rate to the I and Q modulator inputs. The resulting signal (from an ideal modulator) would be a single frequency component offset from the carrier frequency by exactly +0.25 times the bit rate. The amplitude of this component would be equal to 0 dBc. If modulator errors exist (they always will), additional frequencies will appear in the spectrum as shown in Figure A-20. The spectral line at a normalized frequency of 0 (carrier frequency) is referred to as the remnant carrier. This component is largely caused by direct current imbalances in the I and Q signals. The remnant carrier power in Figure A-20 is approximately −31 dBc. Well-designed FQPSK-B transmitters will have a remnant carrier level less than −30 dBc. The spectral component offset, 0.25 times the bit rate below the carrier frequency, is the other sideband. This component is largely caused by unequal amplitudes in I and Q and by a lack of quadrature between I and Q. The power in this component should be limited to −30 dBc or less for good system performance.
Figure A-20. FQPSK-B Spectrum with All 0’s Input and Large Modulator Errors
Figure A-21 shows the measured BEP versus signal energy per bit/noise power per Hz (Eb/N0) of two FQPSK-JR modulator/demodulator combinations including nonlinear amplification and differential encoding/decoding in an additive white Gaussian noise (AWGN) environment with no fading. Other combinations of equipment may have different performance.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
Phase noise levels higher than those recommended in Chapter 2 can significantly degrade the BEP performance. Computer simulations have shown that a BEP of 10−5 may be achievable with an Eb/N0 of slightly greater than 11 dB (with differential encoding/decoding). The purpose of the differential encoder/decoder is to resolve the phase detection ambiguities that are inherent in QPSK, OQPSK, and FQPSK modulation methods. The differential encoder/decoder used in this standard will cause one isolated symbol error to appear as two bits in error at the demodulator output; however, many aeronautical telemetry channels are dominated by fairly long burst error events, and the effect of the differential encoder/decoder will often be masked by the error events.
Figure A-21. FQPSK-JR BEP vs. Eb/N0 A.9. SOQPSK-TG Characteristics
The SOQPSK is a family of constant envelope CPM waveforms defined by Hill.29 The details of SOQPSK-TG are described in Subsection 2.3.3.2. The SOQPSK-TG signal amplitude is constant and the phase trajectory is determined by the coefficients in Table 2-4. Therefore, SOQPSK-TG can be implemented using a precision phase or frequency modulator with proper control of the phase trajectory. Figure A-22 illustrates the measured phase trajectory of an SOQPSK-TG signal. The vertical lines correspond approximately to the “bit” decision times.
Figure A-22. Measured SOQPSK-TG Phase Trajectory
29 Hill, “An Enhanced, Constant Envelope, Interoperable Shaped Offset QPSK.”
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
The power spectrum of a random 5-Mbps SOQPSK-TG signal is shown in Figure A-23. B-60dBc of this 5-Mbps signal was about 7.34 MHz. Note that the maximum power level is about −19 dBc.
Figure A-23. SOQPSK-TG Power Spectrum (5 Mbps) Figure A-24 shows the measured BEP versus signal energy per bit/noise power per Hz (Eb/N0) of two SOQPSK-TG modulator/demodulator combinations including nonlinear amplification and differential encoding/decoding in an AWGN environment with no fading. Other combinations of equipment may have different performance. Phase noise levels higher than those recommended in Chapter 2 can significantly degrade the BEP performance.
Figure A-24. BEP vs. Eb/N0 Performance of 5 Mbps SOQPSK-TG A.10. Advanced Range Telemetry Continuous Phase Modulation Characteristics
The ARTM CPM is a quaternary signaling scheme in which the instantaneous frequency of the modulated signal is a function of the source data stream. The frequency pulses are shaped for spectral containment purposes. As defined for this standard, the modulation index alternates at the symbol rate between h=4/16 and h=5/16. The purpose of alternating between two modulation indices is to maximize the minimum distance between data symbols, which results in
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
minimizing the BEP. These particular modulation indices were selected as a good tradeoff between spectral efficiency and data-detection ability. Figure A-25 shows the power spectrum of a 5-Mbps ARTM CPM signal and Figure A-26 shows the measured BEP versus Eb/N0. The maximum power level was about −19 dBc. B-60dBc of this 5-Mbps signal was about 5.54 MHz. Note that the power spectrum of ARTM CPM is about 25% narrower than that of SOQPSK-TG but the BEP performance is worse. The ARTM CPM is also more susceptible to phase noise than SOQPSK-TG.
Figure A-25. Power Spectrum of 5 Mbps ARTM CPM
Figure A-26. BEP vs. Eb/N0 Performance of 5 Mbps ARTM CPM A.11. PCM/FM
The most popular telemetry modulation since 1970 is PCM/ FM, also known as CPFSK. The RF signal is typically generated by filtering the baseband NRZ-L signal and then frequency modulating a VCO. The optimum peak deviation is 0.35 times the bit rate (h=0.7) and a good choice for a premodulation filter is a multi-pole linear phase filter with bandwidth equal to 0.7 times the bit rate. Figure A-27 shows the power spectrum of a pseudo-random 5-Mbps PCM/FM signal with peak deviation of 1.75 MHz and a 3.5-MHz linear phase low-pass filter. Note that the spectrum is nearly flat from a frequency equal to −0.5 times the bit rate to a frequency equal to +0.5 times the bit rate. The power level near the center frequency is about −22.5 dBc for a bit rate of 5 Mbps and the standard spectrum analyzer settings.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
Figure A-27. Power Spectrum of 5 Mbps PCM/FM Signal Figure A-28 shows the BEP versus Eb/N0 performance of 5-Mbps PCM/FM with a multisymbol bit detector and with three different receivers/detectors. Note that an Eb/N0 of about 9.5 dB is required to achieve a BEP of about 10−5 with the multi-symbol detector30, 31 while an Eb/N0 of about 12 to 14 dB is typically required to achieve a BEP of about 10−5 with typical FM demodulators and single-symbol detectors. The PCM/FM modulation method is fairly insensitive to phase noise.
Figure A-28. BEP vs. Eb/N0 Performance of 5-Mbps PCM/FM with Multi-Symbol Bit Detector and Three Single-Symbol Receivers/Detectors A.12. Valid Center Frequencies Near Telemetry Band Edges The telemetry bands and associated frequency ranges identified in Table 2-1 identify the frequency limits for each band. Telemetry transmitters cannot be centered at the band edges due to obvious out-of-band emissions (OOBE). Bit rate to the transmitter and modulation scheme drive the amount of separation required between the center frequency and the band edge. To
30 Osborne, W. P. and M. B. Luntz. “Coherent and Noncoherent Detection of CPFSK,” IEEE Transactions on Communications, August 1974. 31 Mark Geoghegan. “Improving the Detection Efficiency of Conventional PCM/FM Telemetry by using a MultiSymbol Demodulator”, Proceedings of the 2000 International Telemetry Conference, Volume XXXVI, 675-682, San Diego CA, October 2000.
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determine the amount of back-off required, the distance from the center of the spectral masks for each modulation scheme (see Subsection 2.3.6) to the intersection of the mask and the absolute limit of −25 dBm must be calculated. To illustrate this, see Figure A-29. Using these calculations will assure that outside the specified telemetry bands no part of the modulated spectrum is over the absolute limit of −25 dBm.
Power Spectral Density Masks
0

-10

-20

dBc (in 30 kHz BW)

-30 ARTM CPM SOQPSK/FQPSK PCM/FM
-40

-50

-60

-70

-15

-10

-5

0

5

10

15

Frequency Offset from Carrier (MHz)

Figure A-29. Spectral Masks at −25 dBm

The mask is calculated for all the modulation schemes at a bit rate of 5 Mbps with transmitter output power assumed to be 10 W. This transmitter operating with PCM/FM as its modulation scheme requires a back-off from band edge of 9.98 MHz; since channelization in these bands is limited to 0.5-MHz steps, this value is rounded up to 10 MHz. This same transmitter operating with SOQPSK/FQPSK will require 4.67 MHz, rounded up to 5 MHz, of back-off from band edge. Likewise, for ARTM-CPM the back-off is 3.54 MHz or 4 Mbps when rounded up. To further this example, if this was an L-band transmitter, viable carrier frequencies would be as specified in Table A-4.

Table A-4. L-Band Frequency Range (10 W, 5 Mbps)

Modulation Type PCM/FM SOQPSK/FQPSK ARTM CPM

Viable L-Band Frequency Range 1445-1515 MHz 1440-1520 MHz 1439-1521 MHz

For a given modulation scheme and transmitter output power, as the bit rate increases, the amount of back-off from the band edge also increases. Figure A-30 illustrates this point.

A-29

Backoff from Band Edge (MHz)

Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

Required Band-Edge Backoff

40

35

30

25

PCM/FM

20

SOQPSK/FQPSK

ARTM CPM

15

Carrier Power (dBm):

40

10

5

0

0

5

10

15

20

25

Bit Rate (Mbps)

Figure A-30. Bit Rate vs. Band Edge Back-off

For ease in making calculations, an Excel spreadsheet application can be used. Table A-5 provides an example of a 10-watt transmitter operating at 1 Mbps in L-band and S-band using the formulas in the spreadsheet. The Excel file that created Table A-5 can be downloaded here and used for interactive calculations.

The input values for transmitter output power and bit rate are in the cells highlighted in yellow. The amount of back-off will be displayed in the cells highlighted in light blue. Additionally, each telemetry band is displayed with the useable carrier frequency range for each modulation scheme given in blue.

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Table A-5. Valid Center Frequency, Band Edge Back-Off

Carrier Power or EIRP (dBm): Mask floor (at this nominal TX power):
Bit Rate (Mbps):

40 −65
1.00 PCM/FM

Input Number dBc
1.00 SOQPSK/FQPSK

1.00 ARTM CPM

Input Number

K = m = Bit Rate (bps) Mask hits floor at offset of (MHz) Band-edge backoff (MHz, rounded to nearest 0.5 MHz)

−28 2
1.00E+06 2.34
2.5

−61 4
1.00E+06 1.10
1.5

−73 4
1.00E+06 0.83
1

Result

LBand

Band Edge, Lower (MHz) Band Edge, Upper (MHz) Lower center freq. at this bit rate (MHz) Upper center freq. at this bit rate (MHz)

1435 1525 1437.5 1522.5

1436.5 1523.5

1436.0 1524.0

LBand

Band Edge, Lower (MHz) Band Edge, Upper (MHz) Lower center freq. at this bit rate (MHz) Upper center freq. at this bit rate (MHz)

1755 1850 1757.5 1847.5

1756.5 1848.5

1756.0 1849.0

SBand

Band Edge, Lower (MHz) Band Edge, Upper (MHz) Lower center freq. at this bit rate (MHz) Upper center freq. at this bit rate (MHz)

2200 2290 2202.5 2287.5

2201.5 2288.5

2201.0 2289.0

SBand

Band Edge, Lower (MHz) Band Edge, Upper (MHz) Lower center freq. at this bit rate (MHz) Upper center freq. at this bit rate (MHz)

2360 2395 2362.5 2392.5

2361.5 2393.5

2361.0 2394.0

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Properties of the Differential Encoder Specified in IRIG Standard 106 for OQPSK Modulations
B.1. Introduction
This appendix summarizes a study of the differential encoder originally adopted by the US DoD ARTM project and the RCC and incorporated into the IRIG 106 for FQPSK-B modulation. The study, performed by Mr. Robert Jefferis of the TYBRIN Corporation, was prompted by inquiries from industry representatives who were concerned that this particular differential code was not associated with commercial telecommunication standards and the fact that manufacturers had experienced confusion over correct implementation. The study results shown in this appendix prove the code to be robust, reliable, and applicable to SOQPSK-TG as well as FQPSK-B and FQPSK-JR.32
This appendix is organized along the following structure. Section B.2 describes the need for differential encoding. Section B.3 explains the IRIG-106 differential code for OQPSK. Section B.4 demonstrates differential code’s invariance with respect to constellation rotation. Section B.5 shows the differential decoder to be self-synchronizing. Section B.6 reviews the differential decoder’s error propagation characteristics. Section B.7 analyzes a recursive implementation of the differential code. Section B.8 describes use of this code with frequency modulator-based SOQPSK transmitters. A description of the implementation of the entire coding and decoding process can be seen at B.10 to this appendix.
B.2. The Need For Differential Encoding
Practical carrier recovery techniques like Costas loops and squaring loops exhibit a troublesome M-fold carrier phase ambiguity. The following paragraphs provide a description of ambiguity problems and how to overcome them.
Figure B-1 shows a simplified quadriphase transmission system that is one of the methods recommended for transparent point-to-point transport of a serial binary data stream. Transparent means that only revenue-bearing data is transmitted. There is no in-line channel coding nor is special bit pattern insertion allowed. The assumption is made for an NRZ-L data stream containing the bit sequence b(nTb) transmitted at rate rb = 1/Tb bits per second. For QPSK and OQPSK modulations, the bit stream is divided into subsets e containing evennumbered bits and o containing odd numbered bits. The transmission rate associated with the split symbol streams is rs = rb/2 symbols per second. Symbol values are converted to code symbols by the differential encoder described in Section B.3. A baseband waveform generator converts the digital symbol time series into continuous time signals suitable for driving the vector modulator as prescribed for the particular modulation in use. Thus, each subset modulates one of two orthogonal subcarriers, the in-phase (I) channel, and the quadrature (Q) channel. The modulator combines these subcarriers, creating a phase-modulated RF signal S(t). On the receive side, demodulation separates the subcarriers, translates them back to baseband, and
32 FQPSK-JR is an FQPSK variant developed by Mr. Robert Jefferis, TYBRIN Corporation, and Mr. Rich Formeister, RF Networks, Inc.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
constructs replicas of the code symbol series E’(nTs) and O’(nTs). Decoding reverses the encoding process and a multiplexer recreates a replica of the bit stream b’(nTb).
Figure B-1. Transmission System Most QPSK and OQPSK systems employ coherent demodulation. Figure B-2 is a simplified diagram of commonly used modulation and demodulation structures. Note the optional single-bit delay shown in the odd symbol path. This creates the significant difference between QPSK and OQPSK, the delay being inserted to create OQPSK.33 Practical carrier recovery techniques like Costas loops and squaring loops exhibit a troublesome M-fold phase ambiguity (M=4 for QPSK and OQPSK).34 Each time the demodulator carrier synchronizer phase locks to the modulator local oscillator its absolute phase relationship to the local oscillator contains the offset term β, which can take on values of 0, ± π/2, or π radians.35
Figure B-2. OQPSK 106 Symbol-to-Phase Mapping Convention
33 The delay can be inserted into either channel. The IRIG-106 convention and most published literature regarding FQPSK and SOQPSK indicate the delay in the odd (or Q) channel. 34 Proakis, J. G. and M. Salehi. Digital Communications. 5th Edition. Boston: McGraw-Hill, 2008. 35 The initial offset angle φ is generally unknown and uncontrolled; it is tracked by the carrier recovery circuitry and the symbol timing circuits automatically ignore.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
The symbol detectors have insufficient information to determine which phase offset exists. They always interpret demodulator output with the assumption that β=0. The resulting constellation axis rotations and their impact on demodulator output are shown at Figure B-3 and Table B-1. The 180° rotation is symmetric. The Axis (subcarrier) assignment is unchanged but the sense (polarity) of both axes gets reversed. The 90° and 270° rotations are asymmetric. Axis assignment is swapped and one axis polarity is reversed in each case.

Figure B-3. Detection Ambiguity

Table B-1.
Rotation 0 π/2 π
3π/2

Constellation Axis Rotations

+I’

+Q’

I

Q

−Q

I

−I

−Q

Q

−I

B.3. A Simple Solution To The Carrier Phase Ambiguity Problem
Differential encoding has been used to work around the carrier ambiguity for many years. For phase modulations, source data is coded such that phase differences rather than absolute phase coordinates become the information-bearing attribute of the signal. The QPSK and OQPSK modulations use I and Q independently, with each channel transporting one symbol stream. Starting with the first binary digit, bit 0, even-numbered bits form the sequence {ek} and odd-numbered bits form the sequence {ok+1} where the counting index is changed from the bit index n to the symbol pair index

(B-1)
Figure B-4 illustrates how QPSK modulators process bits in pairs (dibits), mapping and asserting time coincident symbol phase coordinates (Ik,Qk).36 Phase state changes commence and end on symbol interval timing boundaries, each state taking on one of four possible values at detector decision instants; however, the case of interest is shown in Figure B-5.

36 Rectangular I and Q baseband waveforms are used only for illustration.

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Figure B-4. QPSK State Timing

Figure B-5. OQPSK State Timing
The Q channel half-symbol delay causes OQPSK phase trajectories to evolve on a halfsymbol (bit) rate basis. For the particular cases of FQPSK and SOQPSK-TG, carrier phase either remains unchanged or changes by ±π/4 or ±π/2 radians over the pending bit interval.
The OQPSK inter-channel delay might at first seem a difficult complication because it creates additional ambiguity; in other words, the receiver must resolve relative inter-channel delay; however, as shown below, this is not a problem.
The differential encoding rule adopted in IRIG-106 for OQPSK appears in Feher37 and is therein attributed to Clewer38 and Weber.39 Bit by bit, the code symbol sets {Ek} and {Ok+1) are formed with the Boolean expressions:

(B-2a) (B-2b)

(B-2)

37 Kamilo Feher. Digital Communications: Satellite/Earth Station Engineering. Englewood Cliffs: Prentice-Hall, 1983, pp. 168-170. 38 R. Clewer. “Report on the Status of Development of the High Speed Digital Satellite modem”, RML-009-79-24, Spar Aerospace Limited, St. Anne de Bellevue, P.Q., Canada, November 1979. Quoted in Kamilo Feher. Digital Communications: Satellite/Earth Station Engineering. Englewood Cliffs: Prentice-Hall, 1983. 39 W. J. Weber III. “Differential Encoding for Multiple Amplitude and Phase Shift Keying Systems.” In IEEE Transactions on Communications, Vol. COM-26, No. 3, March 1978.
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Two bits are coded for each value of k in a two-step process. First, the even symbol Ek is coded with current bit ek. Then the next bit, ok+1 becomes current and the odd symbol Ok+1 is computed. In each code set the exclusive-or operator is applied to the state defining variables just like binary phase shift keying (BPSK) differential encoding. Unlike BPSK however, the current source bit and the most recent code symbol from the other channel determine adjacent phase transitions. The inverted code symbol in equation B-2a introduces asymmetry in the equations. Its significance will become evident in the next section.
The code symbol sets {E} and {O} are applied to the I and Q channels of the OQPSK modulator. The initial assignment of {E} to either I or Q can be made arbitrarily; however, with this code definition, once the choice is made at the modulator, decoding will fail if channel assignment conventions change anywhere during the transmission or decoding processes. Thus, the assignment convention must extend to the physical modulator and demodulator. The IRIG106 assigns I to the physical I subcarrier (also known as the “real” or “cosine” subcarrier) and Q is applied to the physical Q subcarrier (also known as the “imaginary” or “sine” subcarrier). In order to stress this assignment convention, IRIG-106 expresses equation B-2 explicitly in terms of the I and Q channel variables:

(B-3a) (B-3b)

(B-3)

Decoding is straightforward. When β=0, I’=I, and Q’=Q, inspection of the following truth tables reveals simple decoding instructions:

Equation B-3a

Equation B-3b

Ik Q(k −1) ek 000 011 101 110

Q(k +1) I k o(k +1) 0 00 1 0 1 ⇒ decoding equation 0 11 1 10

Equation B-3

(B-4a) (B-4b)

(B-4)

The equations at B-3 may not convey an intuitive sense of the shift from absolute phase states to phase differences. Extending B-3a backwards in time by substituting B-3b into B-3a results in:

( ) ( ) I k = ek ⊕ ok−1 ⊕ I k−2 = I k−2 ⊕ ek ⊕ ok−1

(B - 5)

Similarly, for the next bit interval the results are:

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

( ) ( ) Qk+1 = ok+1 ⊕ ek ⊕ Qk−1 = Qk−1 ⊕ ok+1 ⊕ ek

(B - 6)

This recursive form clearly shows that on a bit-by-bit basis, the current and most recent bits control phase trajectory motion, not absolute phase. Note that B-5 and B-6 do not define the sign of a phase change. Predictable decoder output requires that two additional conventions be established and maintained. Boolean logic polarity conventions used throughout the system must be consistent. The IRIG-106 assumes positive true logic. Finally, sign conventions and channel assignment used within the transmitter (baseband signal generator and modulator) and the receiver (demodulator) must be constrained to produce a consistent code symbol-to-phase mapping convention. The IRIG-106 convention is shown in Figure B-2. For example, if {b} were to consist entirely of logic one values, i.e., a run of 1s, the differential encoding process and mapping convention will produce the phase trajectory shown in Table B-2.

Table B-2. Response to Run of 1s

n b(n) k

Ik Qk-1 Qk+1

0 1 0 0 0*

1 1

1

2 1 11 1

3 1

0

4 1 20 0

5 1

1

* denotes assumed initial conditions

Phase (deg)
225* 135 45 315 225 135

Phase ∆
−π/2 −π/2 −π/2 −π/2 −π/2

The trajectory spins clockwise, and the phase is retarded by 90° during each bit interval.40 Obviously, any single (unbalanced) sign change and any change to the mapping convention will alter the trajectory.
B.4. Immunity to Carrier Phase Rotation The equations at B-3 and B-4 are invariant with respect to cardinal constellation rotation
as shown in the following. Proof:
The β=0 case is decoded correctly by definition according to equations B-5 and B-6. At Table B-1, when β = π there is no axis swap but the decoder is presented with
I'k = Ik Q'k +1 = Qk +1
Decoding will progress as follows: Step 1. Even channel; apply equation B-4a;

40 FQPSK-B, FQPSK-JR, and SOQPSK-TG modulations respond to a run of 1s with an S(t) that is ideally, a pure tone at frequency fc-rb/4 Hz. This is referred as “lower sideband” mode. Similarly, a run of zeroes will produce a constant anti-clockwise trajectory spin and a tone at fc+rb/4 Hz (“upper sideband” mode).
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
e'k = I'k ⊕ Q 'k −1 = I k ⊕ Qk −1 = I k ⊕ Qk −1 = ek
Step 2. Odd channel; apply equation B-4b; o'k +1 = Q'k +1 ⊕I 'k = Qk +1 ⊕ I k = Qk +1 ⊕ I k = ok +1
Thus, symmetric rotation is transparent to the code. When β=π/2 the decoder sees the following.
I 'k = Qk −1 Q'k +1 = Ik
Decoding takes place in the same sequence: Step 1. Even channel, apply equation B-4a;
e'k = I'k ⊕ Q 'k−1 = Qk−1 ⊕ I k = I k ⊕ Qk−1 = ok−1
Step 2. Odd channel, apply equation B-4b; o'k +1 = Q'k +1 ⊕I 'k = I k ⊕ Qk −1 = ek
In this case the bit sequence is recovered correctly and the code definition coupled with consistent sign conventions automatically compensates for the asymmetric rotation by reversing the application order of B-4a and B-4b. As a result, the output indices are shifted back in time one bit period. Asymmetric rotation causes a one-bit delay in the decoding process. Finally, the same result is seen when β=3π/2:
I 'k = Qk−1 Q'k+1 = I k
Step 1. Even channel; apply equation B-4a; e'k = I'k ⊕ Q 'k −1 = Qk −1 ⊕ I k = I k ⊕ Qk −1 = ok −1
Step 2. Odd channel; apply equation B-4b;
o'k +1 = Q'k +1 ⊕I 'k = I k ⊕ Qk −1 = I k ⊕ Qk −1 = ek
In all cases the decoder correctly reproduces the original bit sequence. Decoding is instantaneous for symmetric rotations but it is delayed by one bit in 2 out of 4 possible asymmetric rotation startup scenarios.
The need for consistent function assignment now becomes clear. Application of B-4b to a code symbol formed with B-3a produces the complement of the original bit. Likewise, application of B-4a to a symbol coded with B-3b inverts the result.
At this point, the OQPSK inter-channel delay ambiguity mentioned in Section B.2 has not been resolved. The roles of I’ and Q’ reverse with asymmetric rotations and there is no way to determine when this occurs; however, as long as the code symbol time sequence is preserved
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
at the decoder and the roles of I’ and Q’ do not get reversed in terms of the application of B-6a and B-6b, inter-channel delay is transparent to the code with respect to reconstruction of the original data sequence.41
B.5. Initial Values Equations B-3 and B-4 do not impose any implementation constraints on initial values
when encoding or decoding starts. To confirm this it is assumed that hardware power-up (or initial data presentation) may cause encoding to commence with either channel. It is further assumed that no provisions for specific initial values in encoder and decoder state memories have been made. If coding starts with I (see equation B-3a), the first code symbol will be computed:
I 0 = e0 ⊕ Q−1
where 〈.〉 denotes an unknown initial value and double vertical bars denote computed values influenced by initial values. Encoding equations B-3a and B-3b will progress as follows:
Q1 = o1 ⊕ I0
I 2 = e2 ⊕ Q1
The initial values do establish the absolute sense of code symbols for the duration of transmission; but, on both ends of the process, two of three terms in every equation are affected consistently by the initial value, which by symmetry has no effect on the outcome of exclusive-or operations. Obviously, identical results occur if the encoder starts with Q. Independent of starting channel and initial value then, the first and all subsequent adjacent code symbol pairs contain valid state change information.
Initial decoder values can produce errors. Again starting with I, and using equations B-4a and B-4b, decoding will progress as follows:
e'0 = I '0 ⊕ Q−′1
o'1 = Q '1⊕I '0
It is seen that on the second cycle the initial value of the decoder has been flushed out. At most, one bit will be decoded in error. Similarly, if decoding starts with Q, output will progress:
o'1 = Q '1⊕ I '0
e'2 = I '2 ⊕Q '1
Again, only the first decoded bit may be incorrect. The conclusion, then, is that initial values can produce at most one decoded bit error; however, there is another source of startup
41 If for some reason the system application requires that one can determine whether a specific symbol was originally transmitted via I or Q, then this code is not appropriate.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
errors that is seen as an initial value problem. Section B.4 showed that odd phase rotations (π/2 and 3π/2) cause a single bit delay in the decoder. Examining this further, the first symbol index value will be k = 0. If the decoder starts with equation B-4a, the first decoded bit will be:
e0′ = I0′ ⊕ Q−′1 = I0 ⊕ Q−1 = o−1
If the decoder starts with equation B-4b the first result will be:
o1′ = Q1′ ⊕ I0′ = I0 ⊕ Q−1 = e0
The first case produces the aforementioned delay. The decoder emits an extra bit. The second bit emitted is actually the first bit of the sequence reconstruction and is still subject to the single initial value error probability of startup processing. The latter case does not produce a delay; it only presents the possibility of a first bit decoding error.
B.6. Error Propagation Differential encoding incurs a bit error penalty because received code symbols influence
more than one decoded bit. First consider a single-symbol detection error in current symbol E’ that is labeled εk. The following sequence of decoding steps shows how the error propagates. Since the E channel was chosen as current, decoding starts with equation B-4a. The single detection error creates two sequential decoding errors. By symmetry we can state that the same result occurs if a single error occurs in O’.
b'k = ε k ⊕ Qk−1 = bk ⇒ error b'k+1 = Qk+1 ⊕ ε k = bk+1 ⇒ error b'k+2 = E'k+2 ⊕Q'k+1 = bk+2 ⇒ correct
Next is the case of two symbol detection errors occurring consecutively on E’ and O’, i.e., detectors emit error symbols E’k=εk and O’k+1=εk+1. Starting again with equation B-4a yields:
b'k = ε k ⊕ Q(k−1) = bk ⇒ error b'(k+1) = ε (k+1) ⊕ ε k = O'(k+1) ⊕Ek = b(k+1) ⇒ correct b'(k+2) = E'(k+2) ⊕ε (k+1) = b(k+2) ⇒ error b'(k+3) = O'(k+3) ⊕E'(k+2) = b(k+3) ⇒ correct
Two consecutive symbol errors produce two decoding errors but the errors are not adjacent. The conclusion from this is that symbol detection errors influence no more than two decoding cycles, i.e., the maximum error multiplication factor is 2.
B.7. Recursive Processing and Code Memory Most systems reconstruct the original bit rate clock and {b} by merging {e’} and {o’}.
For a variety of reasons, designers might be tempted to multiplex {I’} and {Q’} into a bit rate code symbol sequence {Bn} prior to decoding; however, the same considerations that foster
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

desire for post-multiplex decoding are likely to be accompanied by loss of transmitted code symbol order, i.e., loss of knowledge whether a given code symbol came from I or Q. The question arises as to whether {Bn} alone contains enough information for unique decoding. The answer is no, and the proof is shown below.
Proof:
A decoding function can be derived by inspection of equations B-5 and B-6. Equation B-5 can be rearranged as follows:

I k = ek ⊕ ok−1 ⊕ I k−2

(B - 7)

Similarly, from equation B-6 we can write
Qk+1 = ok+1 ⊕ ek ⊕ Qk−1

(B - 8)

Here are two instances of a seemingly identical recursive relationship, i.e., the current code symbol is the difference between the current bit, the previous bit, and the inverse of the most recent code symbol from the current channel. We can consolidate these equations by converting to post-multiplex bit rate indexing, i.e.,

Bn = bn ⊕ b(n−1) ⊕ B(n−2)

(B - 9)

from which we can immediately write the decoding function b'n = b'(n−1) ⊕B'n ⊕B '(n−2)

(B -10)

On the surface it seems that equation B-10 will work;42 however, these relations involve two differences, rather than one, and therefore introduce superfluous initial condition dependence. For brevity, only the pitfalls of B-10 are examined herein, assuming that a nonrecursive encoder is used. From startup, decoding will progress as follows.
b'0 = b'−1 ⊕ B'0 ⊕ B '−2
b'1 = b'0 ⊕ B'1⊕ B '−1
b'2 = b'1 ⊕ B'2 ⊕B '0 b'3 = b'2 ⊕ B'3⊕B '1

.

.

.

As seen, absolute polarity of the first and all subsequent decoded bits is determined by three initial values. Absent appropriate side information for selecting initial values, the postmultiplex decoder offers a 50-50 chance of decoding with correct polarity. The code sequence

42 The interested reader is left to confirm that equation C-10 is indeed rotation invariant.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
defined by equations at B-3 has a two-symbol memory. Additional symbols do not provide new information regarding the trajectory history. Another way to view this problem is to note that this recursive decoder does not guarantee preservation of symbol order, which is a prerequisite to reliable decoding.
B.8. Frequency Impulse Sequence Mapping for SOQPSK
The SOQPSKs first described by Hill43 and Geoghegan44 are defined as special cases of CPM. Since 1998, at least two manufacturers have exploited the fact that modern digital waveform synthesis techniques enable direct implementation of the CPM equations with virtually ideal frequency modulators and filter impulse responses. A generic model of these implementations is in Figure B-6. The I and Q channels, per se, do not exist in this transmitter. At the beginning of each bit interval, impulses from the bit-to-impulse alphabet mapper direct the impulse filter/frequency modulator to advance the carrier phase by 90°, retard it by or 90°, or leave the phase unchanged. This is accomplished with a ternary alphabet of frequency impulses having normalized amplitudes of {−1,0,1}.45 This structure cannot be mapped directly into the constellation convention of a quadriphase implementation because there is no way to control absolute phase. The equations at B-3 can be applied to this non-quadrature architecture via precoding. A general treatment SOQPSK pre-coding is contained in Simon.46 The pre-coding truth table given in Table B-3 applied to the model in Figure B-7 will yield a phase trajectory history identical to one generated by the quadriphase counterpart of Figure B-2 using the equations at B3; however, one more constraint is necessary to establish compatibility with the IRIG-106 quadriphase convention. Table B-3 assumes the stipulation that positive sign impulse values will cause the modulator to increase carrier frequency.

Figure B-6. SOQPSK Transmitter

Table B-3. SOQPSK Pre-Coding Table for IRIG-106 Compatibility

MAP αK FROM IK

MAP αK+1 FROM QK+1

Ik

Qk−1

Ik−2

∆Φ

αk

Qk+1

Ik

Qk−1

∆Φ

αk+1

−1

X*

−1

0

0

−1

X*

−1

0

0

+1

X*

+1

0

0

+1

X*

+1

0

0

−1

−1

+1 −π/2 −1

−1

−1

+1 +π/2 +1

43 Hill, “An Enhanced, Constant Envelope, Interoperable Shaped Offset QPSK.” 44 Geoghegan, “Implementation and Performance Results.” 45 The so-called ternary alphabet is actually 2 binary alphabets {-1,0} and {0,1}, the appropriate one chosen on a bit-
by-bit basis according to certain state transition rules. 46 Marvin Simon. “Multiple-Bit Differential Detection of Offset Quadriphase Modulations.” IPN Progress Report 42-151. 15 November 2002. Jet Propulsion Laboratory, Pasadena, CA. Retrieved 4 June 2015. Available at
http://ipnpr.jpl.nasa.gov/progress_report/42-151/151A.pdf.

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

−1

+1

+1 +π/2 +1

−1

+1

+1 −π/2 −1

+1

−1

−1 +π/2 +1

+1

−1

−1 −π/2 −1

+1

+1

−1 −π/2 −1

+1

+1

−1 +π/2 +1

* Note: Does not matter if “X” is a +1 or a −1

Figure B-7. OQPSK Transmitter (With Precorder)
B.9. Summary
This investigation confirmed that the differential encoder defined in the equations at B-3 is entirely satisfactory for SOQPSK, FQPSK-JR, and FQPSK-B systems where conventional coherent demodulation and single-symbol detection is used. In addition, a method of extending this code to SOQPSK is presented without proof.
Specifically, the following has been shown.
a. When accompanied by consistent sign conventions, a consistent symbol-to-phase mapping rule, and preservation of symbol order, the OQPSK differential code defined in B-3 and the decoding rule defined in B-4 is rotation invariant and unambiguously reconstructs the original data bit sequence.
b. Decoding is instantaneous.
c. Equations B-3 and B-4 do not require attention to initial values.
d. At most, two consecutive output bits will be in error after carrier and symbol synchronization is acquired.
e. The recursive relations in equations B-9 and B-10 are ambiguous and therefore unreliable.
f. The code exhibits a detection error multiplication factor of at most two.
B.10. System-Level Software Reference Implementation of Differential Encoder Defined in IRIG Standard 106 for FQPSK and SOQPSK Modulations
B.10.a. Introduction
The Matlab®™ program listings below provide a Matlab function “Desysdemo” and an execution control script “runDEdemo”. In the context of differential encoding, the function provides a complete system simulation including a differential encoder, an ideal vector modulator, channel phase rotation, demodulation, the functional equivalent of an ideal singlesymbol sample and hold detector, and a decoder. The user can create sample data vectors or use the example data provided. In addition, the user can manipulate the initial value vectors to
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

explore all possible initial value and demodulator phase rotation combinations of the quadriphase implementation model.
By setting the variable “style” to zero, the function will also emulate the pre-coded frequency modulator architecture required for SOQPSKs; however, the initial value of transmitter carrier phase is hard-coded at 45°. This was done to avoid proliferation of initial value options and is thought to be an insignificant omission because it does not affect generality of the phase rotation options.
This material assumes that the user is familiar with Matlab workspace operation. The program relies only on basic Matlab license libraries. No special toolboxes or blocksets are required.

B.10.b. Matlab Workspace Operation

The user should place the script (shown below in Section B.10.c) in the directory of choice and make that directory current in the workspace. In order to execute the canned example, the user needs to create the variable “example” in the workspace and set its value to 1.

Executing the script “runDEdemo” should produce the output displayed in Table B-1.

Table B-1. Script “runDEdemo” Output

results =

Model: Quadriphase Vector Modulator

Demodulator Phase Rotation = 0°

Initial States: Encoder

Encoder

Memory

Channel

(0,0)

0

Input Bit

TX Phase

RX Phase

1

225

225

1

135

135

1

45

45

0

45

45

0

135

135

1

135

135

0

135

135

1

135

135

1

45

45

1

315

315

0

315

315

0

45

45

1

45

45

0

45

45

Decoder Memory (0,0) Output Bit
1 1 1 0 0 1 0 1 1 1 0 0 1 0

Decoder Channel 0 Decoding Error
0 0 0 0 0 0 0 0 0 0 0 0 0 0

The first column of the results shown above is a replica of the input data vector. The second column shows the initial value-dependent evolution of transmitted phase. The third column shows the effect of any non-zero phase rotation chosen. The fourth column shows the

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
decoded output bit stream. The fifth column flags decoding errors with values of 1. Certain combinations of phase rotation and initial values will produce values of 9 in the fourth and fifth columns; results of this nature are associated with cases that delay the output decoding process by one bit.
Variable definitions and implied instructions for manipulating the runtime options can be obtained by using the normal Matlab help command for these specific programs. B.10.c. Script For Modules
Electronic copies of these programs have been provided to the RCC Telemetry Group. The script for the modules discussed above is shown on the following pages.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

% Control Script ‘runDEdemo’, for running system demonstration

% of differential encoder and phase mapping convention

% defined in RCC standard IRIG-106 for FQPSK-B modulation.

% This version extends demonstration options to the pre-coder

% required for implementing SOQPSK with frequency modulators.

%

% Each example run requires input variables in the Matlab workspace:

%

% “example” - a flag to run with user supplied data vector or run

% the example data set that consists of two repetitions of a

% a 7-bit pseudo random sequence(0=user, 1=example)

% “data” - optional user supplied binary bit sequence (arbitrary

length)

% “rotation_choice” - pointer to demodulator phase rotation options:

% 1=0, 2=pi/2, 3= pi, 4=3*pi/2

% “initTX” - vector of binary encoder startup values:

% initTX(1)= 1st of two encoder code symbol memory values(binary,

arbitrary)

% initTX(2)= 2nd encoder code symbol memory value(binary, arbitrary)

% initTX(3)= starting channel for encoder(binary, 0=I, 1=Q)

% “initRX” - vector of binary decoding startup values

% initRX(1)= 1st of two decoder state memory values(binary, arbitrary)

% initRX(2)= 2nd decoder state memory value(binary, arbitrary)

% initRX(3)= starting channel for decoder(binary, 0=I, 1=Q)

% “style” - 1=quadriphase transmitter architecture (FQPSK)

%

0=frequency modulator transmitter architecture (SOQPSK)

% The example values are:

% data=[1 1 1 0 0 1 0 1 1 1 0 0 1 0]

% rotation_choice=1

% initTX=[0 0 0]

% initRX=[0 0 0]

% style=1

% R.P.Jefferis, TYBRIN Corp., JULY, 2002 % SOQPSK model added 14JUL03 % This version has been tested with Matlab versions:5.2,6.1

% *** Sample Input Setup *** if example
data=[1 1 1 0 0 1 0 1 1 1 0 0 1 0]; rotation_choice=1; initTX=[0 0 0]; initRX=[0 0 0]; style=1; end

% *** Run the Reference Implementation ***

[test,delay]=DEsysdemo(data,rotation_choice,initTX,initRX,style);

% *** Prepare Screen Output ***

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

ROTATION=[0 90 180 270];

if style

results=sprintf('Model: Quadriphase Vector Modulator\n')

else

results=sprintf('Model: Frequency modulator (SOQPSK) model\n')

end

results=[results sprintf('Demodulator Phase Rotation = %3.0f

degrees\n',ROTATION(rotation_choice))];

results=[results sprintf('Initial States: Encoder Encoder Decoder

Decoder\n')];

results=[results sprintf('

Memory Channel Memory

Channel\n')];

results=[results sprintf('--------------------------------------------

----\n')];

results=[results sprintf('

(%d,%d)

%d (%d,%d)

%d\n\n',...

initTX(1:2),initTX(3),initRX(1:2),initRX(3))];

results=[results sprintf(' Input TX

RX Output Decoding\n')];

results=[results sprintf(' Bit Phase Phase Bit Error\n')];

results=[results sprintf('-------------------------------------\n')];

for n=1:length(data)

results=[results sprintf(' %d

%3.0f %3.0f

%d

%d\n',...

test(n,:))];

end

results

% ___________END OF CONTROL SCRIPT_____________

function [result,delay]= DEsysdemo(inbits,rotation_choice,initTX,initRX,style) % Reference simulation for Range Commanders Council standard IRIG 1062000 % FQPSK-B differential encoding and phase mapping convention. % % Input arguments: see “help” for “runDEdemo” script % Output arguments: % “result” - Mx5 matrix,M=number of input bits,columns contain: % (:,1)input bit,(:,2)TX phase,(:,3)RX phase,(:,4)output bit,(:,5)status % “delay” - overall encode/decode process delay in bits

% “TX” prefixes refer to transmitter/encoder variables, “RX” prefixes % refer to receiver/decoder variables % Robert P. Jefferis, TYBRIN Corp., July,2002. % SOQPSK model added 14JUL03 % This version has been tested with Matlab versions: 5.2,6.1 numbits=length(inbits)

% ******************* % * Transmitter * % *******************

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
% *** differential encoder (also SOQPSK pre-coder)****
% encoder memory initial values: % [(last I ch. code symbol) (last Q ch. code symbol)] TXlastSYM=initTX(1:2); % point encoder to either I or Q starting channel(0=I) TXpoint=initTX(3); for n=1:numbits
switch TXpoint case 0
%TXlastSYM % compute “current” I channel code symbol TXnewISYM=xor(inbits(n),~TXlastSYM(2)); TXcodeSYM(n,:)=[TXnewISYM TXlastSYM(2)]; % new phase coordinates(I,Q) TXlastSYM(1)=TXnewISYM; % update encoder memory state TXpoint = ~TXpoint; % point to Q channel eq. for next bit case 1 % compute “current” Q channel code symbol TXnewQSYM=xor(inbits(n),TXlastSYM(1)); TXcodeSYM(n,:)=[TXlastSYM(1) TXnewQSYM]; % new phase coordinates(I,Q) TXlastSYM(2)=TXnewQSYM;% update encoder memory state TXpoint= ~TXpoint; % point to I channel eq. for next bit otherwise disp('Invalid Specification of Encoder starting channel'); end end
% *** modulate ***
switch style case 1 % ** Quadriphase vector modulator **
% RCC IRIG 106 FQPSK-B phase mapping convention: (I,Q) for n=1:numbits
index=floor(2*TXcodeSYM(n,1)+TXcodeSYM(n,2)); switch index case 3 % [1 1]
TXphase(n)=45; % TX phase angle, degrees case 1 % [0 1]
TXphase(n)=135; case 0 % [0 0]
TXphase(n)=225; case 2 % [1 0]
TXphase(n)=315; otherwise, disp('map error') end end case 0 % ** Frequency modulator w/pre-coder **
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
% * pre-coder * % map code symbol sequence to frequency impulse series, alpha(n) alpha=zeros(1,numbits); TXpoint=initTX(3); % in this mode, points to start index for n=3:numbits
if TXpoint % Q(k+1) map if TXcodeSYM(n,2)==TXcodeSYM(n-2,2) elseif xor(TXcodeSYM(n,2),TXcodeSYM(n-1,1)) alpha(n)=-1; else alpha(n)=1; end
else % I(k) map if TXcodeSYM(n,1)==TXcodeSYM(n-2,1) elseif xor(TXcodeSYM(n,1),TXcodeSYM(n-1,2)) alpha(n)=1; else alpha(n)=-1; end
end TXpoint=~TXpoint; % switch to complement function for next bit end
% convert alpha to phase trajectory lastTXphase=45; % initial phase of S(t) for n=1:numbits
TXphase(n)=mod(lastTXphase+alpha(n)*90,360); lastTXphase=TXphase(n); end otherwise end
% ************ % * Receiver * % ************
% *** Demodulator Phase Rotation *** ROTATE=[0 pi/2 pi 3*pi/2]; rotate=ROTATE(rotation_choice); for n=1:numbits
switch rotate case 0
RXphase(n)=TXphase(n); case pi/2
RXphase(n)=mod(TXphase(n)+90,360); case pi
RXphase(n)=mod(TXphase(n)+180,360); case 3*pi/2
RXphase(n)=mod(TXphase(n)+270,360); otherwise end end
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
% *** detector *** for n=1:numbits
switch RXphase(n) case 45
RXcodeSYM(n,:)=[1 1]; case 135
RXcodeSYM(n,:)=[0 1]; case 225
RXcodeSYM(n,:)=[0 0]; case 315
RXcodeSYM(n,:)=[1 0]; otherwise end end
% *** decode and reconstruct data bit sequence ***
% decoder memory initial values: % [(last decoded I channel bit) (last decoded Q channel bit)] RXlastSYM=initRX(1:2); % point decoder channel to either I or Q starting channel (0=I) RXpoint=initRX(3); for n=1:numbits
switch RXpoint case 0
% compute “current” decoded I channel bit RXbits(n)=xor(RXcodeSYM(n,1),~RXlastSYM(2)); RXlastSYM=RXcodeSYM(n,:); % update decoder state RXpoint = ~RXpoint; % point to Q channel eq. for next bit case 1 % compute “current” decoded Q channel bit RXbits(n)=xor(RXcodeSYM(n,2),RXlastSYM(1)); RXlastSYM=RXcodeSYM(n,:); % update decoder state RXpoint= ~RXpoint; % point to I channel eq. for next bit
otherwise end end
% ____________ END OF TX and RX Processing ______________
% ******************* % * Assemble Output * % *******************
% identify delay incurred in overall process offset=xcorr(inbits,RXbits); offset(1:numbits-1)=[]; [offset,delay]=max(offset(1:min(length(offset),10))); delay=delay-1;
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
% adjust RX output bit vector to compensate for delay, % inserting values of 9 at beginning of vector to represent % artifact bits associated with asymmetric rotation cases checkbits=inbits; if delay
newfront=ones(1,delay)*9; checkbits=[newfront inbits]; checkbits(end-delay+1:end)=[]; RXbits(1:delay)=9; end % identify decoding errors in reconstructed bit stream xmsn_error=checkbits~=RXbits; xmsn_error(1:delay)=9; % assemble output matrix result(:,1)=inbits'; result(:,2)=TXphase'; result(:,3)=RXphase'; result(:,4)=RXbits'; result(:,5)=xmsn_error'; % _____END OF FUNCTION DEsysdemo__________
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017
Telemetry Transmitter Command and Control Protocol
C.1. Introduction This appendix provides standards for commands, queries, and status information when
communicating with telemetry transmitters configured with communication ports. The commands are divided into two categories of command sets as follows.
a. Basic. The basic command set contains the minimum (required) commands for transmitter control, query, and status.
b. Extended. The extended command set contains optional commands that may or may not be implemented and may be shown as references.
C.2. Command Line Interface
C.2.a. User Command Line Interface This interface is the default upon power up of the transmitter. Each command or query is
ended by a carriage return <CR>. Information returned from the transmitter will be followed by a carriage return <CR> and the “>” will be displayed to indicate the transmitter is ready to receive commands or queries.
With regard to this standard, it is assumed that a carriage return <CR> is followed by a line feed. The transmitter will return the “OK” mnemonic for each command that is accepted. The transmitter will return “ERR” for a command or query that was interpreted as an error. Verification that a query was either accepted or found to be in error will be the response to the query. All commands are case-insensitive. The transmitter will operate in half-duplex mode and will echo typed characters to the command terminal.
In addition to the required user command line interface items, the following list contains options that may or may not be implemented.
a. Backspacing to correct typed errors. b. A character input to recall the last command line. The “^” character followed by a <CR>
is recommended.
C.2.b. Optional Programming Interface If the transmitter is not commanded or queried though a terminal program (human
interface), there may be an option to operate in half-duplex mode so that concatenated commands can be sent directly to the transmitter (bulk transmitter set-up). If this option is used, the transmitter will only return a single accepted “OK” response if the entire string was interpreted and accepted. When concatenating commands, the semicolon is used as the delimiter for each command. If this optional programming interface is implemented, the transmitter will identify the semicolon delimiter, recognize the character string as a bulk command, and recognize the start of a new command after each delimiter.
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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

C.3. Initialization
Upon successful communication initialization, the transmitter will provide the controlling terminal with (as a minimum) the manufacturer’s name, model number, serial number, and supported IRIG-106 release number. Other information (such as information on firmware and temperature) deemed appropriate by the manufacturer is allowed. This information will be displayed only upon a successful power up and communication initialization of the transmitter. Should an unsuccessful power up occur, based upon criteria of the transmitter manufacturer, the transmitter shall return “ERR” and allow only the RE(RES) command to reset the transmitter (see Subsection C.4.b(9)).
Upon successful communication, after a power up, a communication connection, a command, or a query, the transmitter will send a carriage return followed by a “>“ to signify the transmitter is ready to accept commands and queries.

C.4. Basic Command Set

C.4.a. Basic Command Set Summary

The basic command fields use a minimum two characters with the optional capability of using a maximum of four characters. If possible, the longer four-character field should be used to add intuitiveness to the basic command set. The commands in the basic command set are shown in Table C-1.

Table C-1. Basic Command Set

Command FR(FREQ) MO(MOD) RA(RAND) RF QA(QALL) VE(VERS)
SV(SAVE)
RL(RCLL) RE(RES)
DS(DSRC) CS(CLKS) ID(IDP) IC(ICR) TE(TEMP) FC(FEC) ST(STC)

Function Sets or queries the carrier frequency. Sets or queries the modulation mode. Sets or queries the setting of data randomization (ON or OFF). Sets or queries the RF output (ON or OFF). Queries the status of all basic commands. Queries, at a minimum, the manufacturer’s name, model number, and serial number of the transmitter. Saves the current set-up of the transmitter to on-board nonvolatile random access memory (RAM). Retrieves a transmitter set-up from on-board nonvolatile RAM. Resets the transmitter to a known configuration or restarts the internal powerup sequence. Sets or queries the data source (INT or EXT). Sets or queries the clock source (INT or EXT). Sets or queries the internal data pattern (one of five possible settings). Sets or queries the internal clock rate. Queries the internal temperature (in Celsius). Sets or queries FEC. Sets or queries Space Time Coding.

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

C.4.b. Commands: Basic Command Set

C.4.b(1) Carrier Frequency Carrier frequency is set or queried with the FR(FREQ) mnemonic as described below.

a. Set Frequency. Use “FR(FREQ) XXXX.X <CR>“ where XXXX.X is the commanded frequency in MHz in 0.5-MHz steps. If the command is accepted, an “OK <CR>“ is issued as a response.

In the event of an incorrect commanded carrier frequency (for example the commanded frequency is out of the tuning range of the transmitter), the transmitter will default to the currently set carrier frequency before the command was issued. The transmitter will then return “ERR FR(FREQ) XXXX.X <CR>“ where XXXX.X is the prior frequency set in the transmitter.

b. Query Frequency. “FR(FREQ) <CR>“ queries the currently set carrier frequency and returns “FR(FREQ) XXXX.X <CR>“ where XXXX.X is the current set frequency in MHz.

C.4.b(2) Modulation Mode Modulation mode is set or queried with the MO(MOD) mnemonic.

a. Set Modulation Mode. Use “MO(MOD) X <CR>“ where X corresponds to the modulation mode. If the command is accepted, an “OK <CR>“ is issued as a response.

Command MO(MOD) 0 MO(MOD) 1 MO(MOD) 2 MO(MOD) 6

Modulation Type PCM/FM SOQPSK-TG ARTM-CPM Modulation off (carrier only)

In the event of an incorrect commanded modulation mode, the transmitter will default to the previous modulation mode and return “ERR MO(MOD) X <CR>“ to indicate the error and the current modulation mode. The “MO(MOD) 6” command turns off the modulation for carrier-only mode. Modulation will return upon a new commanded modulation mode. If the transmitter is in single mode, only single mode commands are valid and the above error response will be sent should an invalid modulation mode command be sent. The same logic applies when the transmitter is in dual mode.
b. Query Modulation Mode. “MO(MOD) <CR>“ queries the currently set modulation mode and returns “MO(MOD) X <CR>“ where the integer X is represented in the above table.
C.4.b(3) Data Randomization Data randomization is set or queried with the RA(RAND) mnemonic. For additional
information on randomization, see Subsection 2.3.3.4. This command only enables/disables the randomizer specified in Annex A.2, Figure A.2-2.
a. Set Data Randomization. Use “RA(RAND) X <CR>“ where X corresponds to a 1 or 0. If the command is accepted, an “OK <CR>“ is issued as a response.

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

Command RA(RAND) 1 RA(RAND) 0

Randomization On Off

When FEC is enabled, randomization per Section D.6 should be implemented. If RA(RAND) was enabled prior to enabling FEC, it will be disabled when FEC is enabled. The default state for RA(RAND) will be off when FEC is enabled.

In the event of an incorrect data randomization command, the transmitter will default to its current setting and return “ERR RA(RAND) X <CR>“ to indicate the error and the currently set state. If FC(FEC) is enabled, a “RA(RAND) 1” command will return an ERR RA(RAND) 1<CR>.

b. Query Randomization Mode. “RA(RAND) <CR>“ queries the currently set randomization and returns “RA(RAND) X <CR>“ where integer X is represented in the above table.

C.4.b(4) RF Output The RF output is set or queried with the RF mnemonic.

a. Set RF Output. Use “RF X <CR>“ where X corresponds to a 1 or 0. If the command is accepted, an “OK <CR>“ is issued as a response.

Command RF 1 RF 0

RF Output On Off

In the event of an incorrect RF output command, the transmitter will maintain its current state and return “ERR RF X <CR>“ to indicate the error and return the current RF output setting for the transmitter.

b. Query RF Output. “RF <CR>“ queries the currently set RF output and returns “RF X <CR>“ where X corresponds to the numbers in the above table.

C.4.b(5) Query All The “query all” command is executed with the QA(QALL) mnemonic.

a. Query Transmitter Configuration. The command “QA(QALL) <CR>“ requests the current setting of all basic commands. The transmitter response will contain, as a minimum, the following, in this order:

(1) Carrier Frequency.

[FR(FREQ) XXXX.X]<CR>

(2) Modulation Mode.

[MO(MOD) X] <CR>

(3) Randomization setting.

[RA(RAND) X] <CR>

(4) RF Output setting.

[RF X] <CR> OK<CR>

(5) Data Source.

[DS(DSRC) X] <CR>

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Telemetry Standards, RCC Standard 106-17 Chapter 2, July 2017

(6) Internal Data Pattern

[ID(IDP) X] <CR>

(7) Clock Source

[CS(CLKS) X] <CR>

(8) Internal Clock Rate

[IC(ICR) XX.XXX] <CR>

(9) Internal Temperature

[TE(TEMP) XXX] <CR>

(10) Forward Error Correction [FC(FEC) X] <CR>

(11) Space Time Coding

[ST(STC) X] <CR>

b. Status of Other Commands. If other commands are implemented in the transmitter beyond the basic set, a complete status should be given for each implemented command.

C.4.b(6) Version The “version” command is executed with the VE(VERS) <CR> mnemonic.

a. Query Transmitter Version. “VE(VERS) <CR>“ requests the current version of the transmitter. The response will contain (at a minimum) the following information about the transmitter and in this order:

(1) Manufacturer Name

(2) Model Number

(3) Serial Number

b. Formatting and Delimiting the Fields. It is left up to the transmitter manufacturer to format and delimit the above fields and, if chosen, add additional information to the response.

C.4.b(7) Save The “save” command is executed with the SV(SAVE) mnemonic.

For “Save Transmitter Set-Up”, “SV(SAVE) X<CR>“ saves the current settings of the transmitter to register “X” in nonvolatile memory within the transmitter. If only one location is available, the value of “X” is zero. This document puts no limit to the number of storage registers as this is limited by available nonvolatile memory.

The command “SV(SAVE) <CR>“ will save to the default location 0.

In the event of an unsuccessful save command, the transmitter will return ERR SV(SAVE) X<CR> to indicate the error and no save function will be performed.

In order to avoid the situation of fielding a flight test item that has been inadvertently programmed to use internal clock and data sources, the transmitter power up configuration will always have the clock and data source as external. In addition, when saving to register “0” clock and data sources will always be set to external.

C.4.b(8) Recall The recall command is executed with the RL(RCLL) mnemonic.

For “Recall Transmitter Set-up”, “RL(RCLL) X<CR>“ retrieves and restores the transmitter set-up from register “X” in nonvolatile memory within the transmitter. Values of X start at zero. The “0” register location should be used exclusively for the default set-up, which is the memory location that is loaded during power-up.

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The command “RL(RCLL) <CR> will recall from the default regitster location “0”.

In the event of an unsuccessful recall command, the transmitter will return ERR RL(RCLL) X<CR> to indicate the error and no recall function will be performed.

During a recall operation the transmitter will always set the clock and data sources to external (see Subsection C.4.b(7)).

C.4.b(9) Reset The transmitter can be reset with the RE(RES) mnemonic.

a. Reset Transmitter. “RE(RES) <CR>“ resets the transmitter by reinitializing the transmitter. The transmitter will use the following basic settings as a base configuration.

Transmitter Setting Carrier frequency Modulation mode Differential encoding Randomization RF output Data source Clock source Internal Data Pattern Internal Clock Rate Forward Error Correction Space Time Coding

Command [FR(FREQ)] [MO(MOD)] [DE X] [RA(RAND) X] [RF X] [DS(DSRC)] [CS(CSRC) [ID(IDP)] 11 [IC(ICR)] [FC(FEC)]
[ST(STC)]

Result Lowest valid frequency within the tuning range MO(MOD) 0, PCM/FM DE 0, Differential encoding off RA(RAND) 0, Randomization off RF 0, RF output off DS(DSRC) 0 External CS(CSRC) 0 External [ID(IDP)] 11 PN11 ( 211-1) IC(ICR) 05.000 5 MHz FC(FEC) 0, Forward Error Correction is off
ST(STC) 1, Space Time Coding is on

b. Example Command Use. The Reset command would be used if resetting to a known configuration is required, communication to the transmitter could not be established, if commands were not being recognized, or if some other unknown transmitter state was experienced.

C.4.b(10) Data Source Data source is set or queried with the DS(DSRC) mnemonic.

a. Set Data Source. Use “DS(DSRC) X <CR>“ where X corresponds to a 1 or 0. If the command is accepted, an “OK <CR>“ is issued as a response.

Command DS(DSRC) 0 DS(DSRC) 1

Source External Internal

In the event of an incorrect data source command, the transmitter will return “ERR DS(DSRC) X <CR>“ to indicate the error and return the currently set data source state. b. Query Data Source. “DS(DSRC) <CR>“ queries the currently set data source and returns “DS(DSRC) X <CR>“ where integer X is represented in the above table. c. Saving Data Source. See Subsection C.4.b(7) regarding saving the data source setting.
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C.4.b(11) Clock Source The clock source is set or queried with the CS(CLKS) mnemonic.

a. Set Clock Source. Use “CS(CLKS) X <CR>“ where X corresponds to a 1 or 0. If the command is accepted, an “OK <CR>“ is issued as a response.

Command CS(CLKS) 0 CS(CLKS) 1

Source External Internal

In the event of an incorrect command, the transmitter will return “ERR CS(CLKS) X <CR>“ to indicate the error and the current clock source setting for the transmitter.
b. Query Clock Source. “CS(CLKS) <CR>“ queries the currently set clock source and returns “CS(CLKS) X <CR>“ where integer X is represented in the above table.
c. Example Command Use. Internal data can be clocked either with an external or internal clock. This command allows the user to clock the known data with an existing external clock or select the internal clock for more flexibility.
d. Saving Clock Source. See Subsection C.4.b(7) regarding saving the clock source setting.

C.4.b(12) Internal Data Pattern The internal data pattern is set or queried with the ID(IDP) mnemonic.

a. Set Internal Data Pattern. Use “ID(IDP) X” where X corresponds to the internal data pattern. If the command is accepted, an “OK <CR>“ is issued as a response.

b. Example Internal Data Patterns. Example patterns are shown below.

Command ID(IDP) 9 ID(IDP) 11 ID(IDP) 15 ID(IDP) 20 ID(IDP) 23 ID(IDP) 0000 ID(IDP) FFFF ID(IDP) AAAA ID(IDP) XXXX

Pattern

29−1 211−1 215−1 220−1 223−1

(511 bits) (2047 bits) (32767 bits) (1048575 bits) (8388607 bits)

0x0000

Fixed repeating

0xFFFF Fixed repeating

0101010 Fixed repeating

0xXXXX Fixed repeating

The minimum supported patterns shall be PN11, PN15, and AAAA. Selection of which additional patterns to implement is left up to the manufacturer. If an error occurs, the transmitter will return “ERR ID(IDP) X <CR>“ to indicate the error and return the current data source setting for the transmitter.
c. Query Internal Data Pattern. “ID(IDP) <CR>“ queries the currently set internal data pattern and returns “ID(IDP) X <CR>“ where integer X is represented in the above table.

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d. Example Command Use. This feature can be used for system characterization and troubleshooting. A known bit pattern can be used to test and characterize telemetry systems end-to-end or isolate baseband signal problems to the transmitter.

C.4.b(13) Internal Clock Rate The internal clock rate is set or queried with the IC(ICR) mnemonic.
a. Set Internal Clock Rate. Use “IC(ICR) XX.XXX <CR>“ where XX.XXX corresponds to the clock frequency in MHz and is used to clock the selected internal data pattern. See Subsection C.4.b(12). Actual range for the clock frequency is left to the manufacturer but should correspond to the specified useable input clock frequency range. Resolution should be ±1 kHz. Accuracy for the internal clock is left to the manufacturer but should correspond to internal values for the transmitter. If the command is accepted, an “OK <CR>“ is issued as a response.
In the event of an incorrect command, the transmitter will identify the error, default to its current state, and return “ERR IC(ICR) XX.XXX <CR>“ where “XX.XXX” indicates the current clock source for the transmitter.
b. Query Internal Clock Rate. “IC(ICR) <CR>“ queries the currently set internal clock rate and returns “IC(ICR) XX.XXX” where XX.XXX is the current set internal clock rate in MHz.

C.4.b(14) Internal Temperature Internal temperature is only a query with the TE(TEMP) mnemonic.

Using TE(TEMP) will query the current internal temperature of the transmitter and returns “TE(TEMP) XXX” where XXX is the temperature in Celsius.

C.4.b(15) Forward Error Correction When used, FEC is set or queried with the FC(FEC) mnemonic. If FEC per Appendix 2-
D is implemented in the transmitter, this command will enable, disable, or query the current setting.

a. Set Forward Error Correction. Use “FC(FEC) X <CR>“ where X corresponds to the table below. If X=1, then the command structure is “FC(FEC) 1 xxxx yy <CR>“ where xxxx corresponds to the block size and yy corresponds to the code rate. If the command is accepted, an “OK <CR>“ is issued as a response. When FC(FEC) is enabled, randomization in the transmitter [RA(RAND)] shall be disabled.

Command FC(FEC) 0 FC(FEC) 1 xxxx yy
FC(FEC) X

Source

Block Size

Code Rate

Disable

Enable/Block

1024 or 4096 12 selects 1/2

Size/Code Rate

23 selects 2/3

45 selects 4/5

Future Error Correction Code Capability

In the event of an incorrect FEC command, the transmitter will return “ERR FC(FEC) X <CR>“ to indicate the error and return the current FEC setting for the transmitter.

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