COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
Ref. DTU 100042
Is.Rev. 5.17
Date: Dec. 03, 2021Sept.
30, 2021
This document is the property of Safran Data Systems.
It cannot be duplicated or distributed without expressed written consent.
3.3.1.2.1. Constellation Convention ..................................................................................................................................... 26
3.3.1.2.2. AQPSK Processing............................................................................................................................................... 26
3.3.1.2.3. GMSK Demodulation ........................................................................................................................................... 27
3.3.1.2.4. SOQPSK Demodulation ....................................................................................................................................... 28
3.3.1.2.5. 8PSK Demodulation ............................................................................................................................................. 29
3.3.1.3. FM demodulation ....................................................................................................................................................... 30
3.3.1.3.1. FM Discriminator ................................................................................................................................................. 30
3.3.1.3.2. PCM/FM modulation ........................................................................................................................................... 32
3.3.1.3.3. Supported PCM/FM demodulators ....................................................................................................................... 33
3.3.1.3.4. Multi-Symbol PCM/FM Demodulator – Parameters recommended setting ......................................................... 34
3.3.1.3.4.1. Introduction ......................................................................................................................................... 34
3.3.1.3.4.2. Modulation index ................................................................................................................................ 34
3.3.1.3.4.3. Propagation Factor ............................................................................................................................. 36
3.3.1.4. IF Level Measurement ............................................................................................................................................... 37
3.3.1.5. Low Bandwidth TMU ................................................................................................................................................ 37
3.3.2. IF Carrier Acquisition ................................................................................................................................. 38
3.3.2.1. Acquisition Algorithms .............................................................................................................................................. 38
3.3.2.1.1. FFT – Wide Spectrum .......................................................................................................................................... 38
3.3.2.1.2. FFT – Narrow Spectrum ....................................................................................................................................... 38
3.3.2.1.3. Scanning Sweep ................................................................................................................................................... 38
3.3.2.1.4. Highest Spectrum Line ......................................................................................................................................... 38
3.3.2.1.5. Center Spectrum Line ........................................................................................................................................... 39
3.3.2.1.6. Barycentre Frequency ........................................................................................................................................... 40
3.3.2.1.7. Manual Sweep ...................................................................................................................................................... 41
3.3.2.1.8. Acquisition By-Pass ............................................................................................................................................. 41
3.3.2.2. IF Receiver in Video Mode ........................................................................................................................................ 42
3.3.2.2.1. PM and Coherent AM Demodulation ................................................................................................................... 42
3.3.2.2.2. FM Demodulation ................................................................................................................................................ 42
3.3.2.2.3. By-pass, Spectrum and Non Coherent AM Modes ............................................................................................... 42
3.3.2.3. IF Receiver in PCM Mode ......................................................................................................................................... 43
3.3.2.3.1. PCM/PM Demodulation ....................................................................................................................................... 44
3.3.2.3.2. BPSK, QPSK, OQPSK, SOQPSK GMSK Demodulation .................................................................................... 44
3.3.2.3.3. AQPSK Demodulation ......................................................................................................................................... 44
3.3.3. IF Carrier Tracking ..................................................................................................................................... 45
3.3.3.1. 2
nd
Order PLL ............................................................................................................................................................ 45
3.3.3.2. 3
rd
Order PLL ............................................................................................................................................................. 47
3.3.4. Doppler Measurement ................................................................................................................................. 48
3.3.4.1. Sampling Mode .......................................................................................................................................................... 48
3.3.4.2. Accumulated Phase Format ....................................................................................................................................... 48
3.3.4.3. Interpolation Process .................................................................................................................................................. 49
3.3.4.4. Doppler Computing ................................................................................................................................................... 50
3.3.4.5. Impact of Phase Errors on Doppler Computing ......................................................................................................... 51
3.3.4.6. Sampling Period Resolution ....................................................................................................................................... 51
3.3.4.6.1. Error Due to Computing ....................................................................................................................................... 51
3.3.4.6.2. Error Due to Floating Representation ................................................................................................................... 52
3.3.5. Diversity Combining .................................................................................................................................... 52
3.3.5.1. General ....................................................................................................................................................................... 52
3.3.5.1.1. Post Detection Diversity Combining .................................................................................................................... 53
3.3.5.1.2. Pre Detection Diversity Combining...................................................................................................................... 54
3.3.5.2. Outputs ....................................................................................................................................................................... 55
3.3.5.2.1. Post Detection Diversity Combining .................................................................................................................... 55
3.3.5.2.2. Pre Detection Diversity Combining...................................................................................................................... 56
3.3.5.3. Signal Processing ....................................................................................................................................................... 57
3.3.5.4. Signal Routing ........................................................................................................................................................... 58
3.3.5.5. Dual Polarization and Frequency combining ............................................................................................................. 59
3.3.6. Data Decoding ............................................................................................................................................. 61
3.3.6.1. Descrambling ............................................................................................................................................................. 61
3.3.6.2. Convolutional Decoding ............................................................................................................................................ 62
3.3.6.3. 4D-8PSK-TCM Decoding.......................................................................................................................................... 63
3.3.6.3.1. Introduction .......................................................................................................................................................... 64
3.3.6.3.2. 4D-8PSK-TCM Coder .......................................................................................................................................... 65
3.3.6.3.3. Differential Coder................................................................................................................................................. 66
3.3.6.3.4. Convolutional Coder ............................................................................................................................................ 67
3.3.6.3.5. Constellation Mapper for 4D-8PSK-TCM ........................................................................................................... 68
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