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3.3.4
PCM Decoding
The following codes are supported: NRZ-L/M/S, DNRZ, Bi-P-L/M/S.
When Viterbi decoding is not used, DNRZ is required for ambiguity resolution in QPSK and OQPSK
mode. Several possible DNRZ schemes can be defined, according to the demodulation (QPSK, or
OQPSK).
3.3.4.1
DNRZ, QPSK Decoding (DQPSK)
Several DNRZ algorithms are possible for ambiguity resolution in QPSK mode. The DNRZ code
(algorithm) value can be programmed via Cortex HDR ICD parameter, using examples in next two
sections (CCSDS recommended code and non-CCSDS codes).
3.3.4.1.1
CCSDS Recommended DNRZ Code in QPSK Mode
CCSDS recommendation for DQPSK is:
I
out
Q
out
This is equivalent to the following DQPSK decoding look-up table:
I
© Safran Data Systems – IMP000074 e14r1
HIGH DATA RATE RECEIVER
HDR-4G+ USER'S MANUAL
I
Q
I
I
Q
in
in
out
1
in
in
I
Q
Q
I
Q
in
in
out
1
in
[n-1]
Q
[n-1]
I
dl
dl
dl
0
0
0
0
0
0
0
0
0
1
0
1
0
1
0
1
1
0
1
0
1
0
1
0
1
1
1
1
1
1
1
1
Ref.
Is.Rev
Date:
Q
I
Q
I
out
1
in
in
out
1
I
I
Q
Q
in
out
1
in
in
out
I ˆ
[n]
Q
[n]
in[n]
dl
0
0
1
0
1
1
1
0
0
1
1
0
0
0
0
0
1
1
1
0
0
1
1
1
0
0
1
0
1
0
1
0
1
1
1
0
0
0
0
0
1
0
1
0
1
1
1
1
Safran Data Systems
This document is the property of
It cannot be duplicated or distributed without expressed written consent.
DTU 100782
3.5
June 1, 2021
I
Q
Q
in
in
out
1
I
Q
I
1
in
in
out
1
Q ˆ
in[n]
1
0
1
0
1
1
0
0
0
0
1
1
0
1
0
1
.
Page 91
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