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comparison libgsmhr1/tfo.c @ 604:54f0f1b74c25

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libgsmhr1 TFO: require BFI=0 and SID=0 for homing In order for a received frame to be recognized as DHF, we need not only the correct bit pattern, but also BFI=0 and SID=0. The BFI=0 requirement should be obvious, while the SID=0 requirement is needed only for HR codec. With FR and EFR, SID classification comes from the payload bits and no separate check is needed - but in HR we get an out-of-band SID ternary flag. When SID=1, no payload bits are used at all; when SID=2, we use only the first 33 bits of the payload. Therefore, it is proper to conditionalize DHF acceptance on SID=0. We already implemented this logic in the just finished full decoder; now bring TFO code into agreement.
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 04 Dec 2025 19:40:35 +0000
parents 7d0e565aa1ae
children
comparison
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603:27df1cef042c 604:54f0f1b74c25
23 /* sans-DTX: VAD=1 SP=1 always */ 23 /* sans-DTX: VAD=1 SP=1 always */
24 dl[18] = 1; 24 dl[18] = 1;
25 dl[19] = 1; 25 dl[19] = 1;
26 } 26 }
27 /* homing logic */ 27 /* homing logic */
28 if (!ul[18] && 28 if (ul[18] == 0 && ul[20] == 0 &&
29 !memcmp(ul, gsmhr_dhf_params, sizeof(int16_t) * GSMHR_NUM_PARAMS)) 29 !memcmp(ul, gsmhr_dhf_params, sizeof(int16_t) * GSMHR_NUM_PARAMS))
30 gsmhr_rxfe_reset(st); 30 gsmhr_rxfe_reset(st);
31 } 31 }