Safran CORTEX CRT Quantum - Page 158

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 78
c- External Input to Viterbi Decoder (TMU table/offset 26 = 2. GUI: Frame Sync. Input = Ext. Vit.
1) :
Viterbi
decoder
Differential
decoder
Frame
Synchronizer
I in
PM, FM
demodulator
BPSK S/C,
PCM/PM, PCM/FM
demodulator
Bit synchronizer
IF inputs
Aux. inputs
Aux. inputs
Differential
encoder
Invert/
swap
I out
(Option)
(Option)
Video
out
(Option)
Bi-phase, DM-M
decoder
Figure 38: TM Chain : I/O Ports (HBW with sub-carrier)
 Phase ambiguity solving is by the frame synchronizer or by the differential decoder (if the
PCM code is NRZ-M or NRZ-S).
 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.
 In the case of external Viterbi input (scenario c), only hard-decision is available, with the
corresponding performances.
 Auxiliary inputs: restricted to noise & spurious-free signal with limited amplitude variations.
 Direct input to the PSK Demodulator: set the IF Receiver to « By-pass » mode and select
Auxiliary port # 1 or # 2.
 Option: Direct input to the PSK Demodulator is also accessible using offset 29 in the
telemetry unit table with value 1 or 2.
 Direct input to the Bit Synchronizer: set the IF Receiver to « By-pass » mode and the SCF
to 0 on the Telemetry Unit. Select Auxiliary port # 1 or # 2.
 Option: Direct input to the Bit Synchronizer is also accessible using offset 29 in the
telemetry unit table with value 1 or 2.