Safran CORTEX CRT Quantum - Page 47

COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
Ref. DTU 100042
Is.Rev. 5.17
Date: Dec. 03, 2021Sept.
30, 2021
© Safran Data Systems
This document is the property of Safran Data Systems.
It cannot be duplicated or distributed without expressed written consent.
Page 22
1.6.1.3. Direct PCM Demodulation
1.6.1.3.1. IF Demodulation
 Demodulation PCM/PM, BPSK, QPSK, OQPSK, SOQPSK, GMSK, AQPSK, UQPSK,
8PSK
 Input carrier frequency 60 to 78 MHz
 Carrier acquisition range ± 10 to ± 500 kHz
 Carrier acquisition modes see Section 3.3.2.1
 Demodulation IF bandwidth Automatically adjusted in accordance to the selected bit rate
 Unbalanced QPSK Up to 20 dB unbalance
 Acquisition threshold (CRT XL Quantum)
Eb/No ≤ 0 dB for symbol rates ≥ 1 ksps
IF level ≥ -85 dBm
 Acquisition threshold (CRT eXplorer)
Eb/No ≤ -8 dB or –5 for QPSK modes with 0.01 % PLL BW,
for symbol rates ≥ 10 ksps, IF level ≥ -85 dBm
 Doppler measurement IF offsets and cumulated phase variations (integrated Doppler)
 IF level measurement accuracy < 2 dB
 Diversity combining Pre-detection or post-detection combining (optional)
Up to 3-dB gain with equal-strength signals
 Spectrum analysis Yes (spectrum analysis and IF demodulation are mutually exclusive)
 Adaptive blind equalization (license dependent)
1.6.1.3.2. Bit Synchronization and Decoding
 PCM decoding NRZ-L/M/S, BP-L/M/S, DBP-M/S, DM-M/S, R-NRZ and V35
 Viterbi decoding Rate 1/2 CCSDS 131.0-B-3 (§ 3.3) and 1/3 - Constraint length 7.
 Viterbi depuncturing Rate 2/3, 3/4, 5/6, 7/8 CCSDS 131.0-B-3 (§ 3.4)
From 1/2 rate punctured code. Constraint length 7.
 Tcm decoding Rate 2.00/3, 2.25/3, 2.50/3, 2.75/3.
 Bit rate 100 bps to 20 Mbps (after decoding. License- dependent. See § 3.3.1.2)
 QPSK ambiguities solving - By the frame synchronizer (Synchronization word detection phase)
- Single or dual input Viterbi decoding
- Separate Viterbi decoding on I and Q channels
- Differential QPSK decoding (DQPSK, DOQPSK, DSOQPSK)
See section 3.3.7 for more details
 Matched filter Integral & Dump, Raised Cosine or Root Raised Cosine
 Roll-off factor 0.1 to 1