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Re: [Discuss-gnuradio] gr-fec Viterbi example
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From: |
Jean-Michel FRIEDT |
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Subject: |
Re: [Discuss-gnuradio] gr-fec Viterbi example |
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Date: |
Fri, 10 Aug 2018 09:27:54 +0200 |
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User-agent: |
Internet Messaging Program (IMP) H3 (4.3.7) |
#define POLYA 0x6d
#define POLYB 0x4f
If I modify viterbi.c in gr-fec/viterbi (swapping the polynomial coefficients)
#define POLYB 0x6d
#define POLYA 0x4f
then
$ xxd word.bin
00000000: 1acf fc1d 0000 0000 ........
and
$ cat word.bin | ./encode > t
then t is
0000 0011 0101 1101 0100 1001 1100 0010 0100 1111 1111 0010 0110 1000 0110
0 3 5 D 4 9 C 2 4 F F 2 6 8 6...
=-0xfca2b63db00d9794
so while I am not sure I understand why ones and zeros are swapped using this
encoding, it does seem to me that the two polynomial coefficients of the
LRPT code are swapped in this example.
JM
--
JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe,
25000 Besancon, France
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