Safran CORTEX CRT Quantum - Page 166

COMMAND RANGING & TELEMETRY UNIT CORTEX
CRT QUANTUM USER'S MANUAL
Ref. DTU 100042
Is.Rev. 5.17
Date: Dec.
03, 2021Sept. 30, 2021
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Page 86
c- External Input to Viterbi Decoders (TMU table/offset 26 = 2. GUI: Frame Sync. Input = Ext. Vit.
1) :
Viterbi
decoder
differential
decoder
Viterbi
decoder
differential
decoder
IF inputs
Aux. inputs
interleaving
Frame
Synchronizer
interleaving
differential
encoder
invert/
swap
differential
encoder
I out Q out
BP, DM-M
decoder
Q in I in
PCM/PM,
BPSK,
QPSK,
OQPSK
demodulator
& B/S
(Option)
(Option)
(Option)
I rail
Figure 41: TM Chain : I/O Ports (HBW direct PCM with dual Viterbi)
 Channel and phase ambiguities are solved by the I/Q interleave function (prior frame
synchronization) in the following cases:
 - OQPSK with dual differential encoding,
 - OQPSK with dual [convolutional + differential] encoding.
 Test points and external input to the Frame Synchronizer or Viterbi Decoder are available if
one of the downlink data I/Os Test Sets is enabled. See section 2.3.4.2, Annex 5 and TMU
monitoring table, status offset 26 for more details.
 Hard decision applies to external input to the Viterbi decoders (scenario c).
 Auxiliary inputs: restricted to noise & spurious-free signal with limited amplitude variations.
 Direct input to the Bit Synchronizer: Not available.