HIGH DATA RATE RECEIVER
HDR-4G+ USER’S MANUAL
Ref. DTU 100782
Is.Rev 3.5
Date: June 1, 2021
© Safran Data Systems – IMP000074 e14r1
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There are two conventions for Viterbi puncturing codes. The first is the one which is defined by CCSDS
recommendation and the second can be found on certain commercial encoders. The second
convention only exists for puncturing ratios with an even denominator.
Example: 7/8 punctured Viterbi
Cod0: 1000101
Cod1: 1111010
Conv. 1 pattern: C0(1) C1(1) C1(2) C1(3) C1(4) C0(5) C1(6) C0(7) ...
Conv. 2 pattern: C0(1) C1(1) C1(3) C1(2) C1(5) C0(4) C1(7) C0(6) ...
Convention 2 pattern is convention 1 pattern with each pair of bit swapped apart from the first pair.
The convention can be defined with the registry key VitPunctConv.
The following table shows the effect of the different values of VitPunctConv registry key.
0: depuncturing is defined by the VitPunctSwap registry key as described in the previous chapter
1: VitPunctSwap registry key is ignored. VitPunctCode0 and VitPunctCode1 can be defined
asymmetrically. Convention is 1.
2: VitPunctSwap registry key is ignored. VitPunctCode0 and VitPunctCode1 can be defined
asymmetrically. Convention is 2.
Next figure shows the BER performances of ¾ punctured Viterbi:
1,E-08
1,E-07
1,E-06
1,E-05
1,E-04
1,E-03
1,E-02
1,E-01
2,0 3,0 4,0 5,0 6,0 7,0 8,0
NRZ-L
DNRZ
Viterbi 1/2
viterbi 3/4
Viterbi 3/4 DNRZ
Figure 18: Punctured Viterbi BER Performances
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