static int v29_v21_rx(void *user_data, const int16_t amp[], int len) { fax_state_t *t; fax_modems_state_t *s; t = (fax_state_t *) user_data; s = &t->modems; v29_rx(&s->v29_rx, amp, len); if (t->t30.rx_trained) { /* The fast modem has trained, so we no longer need to run the slow one in parallel. */ span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.29 + V.21 to V.29 (%.2fdBm0)\n", v29_rx_signal_power(&s->v29_rx)); set_rx_handler(t, (span_rx_handler_t *) &v29_rx, (span_rx_fillin_handler_t *) &v29_rx_fillin, &s->v29_rx); } else { fsk_rx(&s->v21_rx, amp, len); if (t->t30.rx_frame_received) { /* We have received something, and the fast modem has not trained. We must be receiving valid V.21 */ span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.29 + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx)); set_rx_handler(t, (span_rx_handler_t *) &fsk_rx, (span_rx_fillin_handler_t *) &fsk_rx_fillin, &s->v21_rx); } } return 0; }
SPAN_DECLARE_NONSTD(int) fax_modems_v29_v21_rx(void *user_data, const int16_t amp[], int len) { fax_modems_state_t *s; s = (fax_modems_state_t *) user_data; v29_rx(&s->fast_modems.v29_rx, amp, len); fsk_rx(&s->v21_rx, amp, len); if (s->rx_frame_received) { /* We have received something, and the fast modem has not trained. We must be receiving valid V.21 */ span_log(&s->logging, SPAN_LOG_FLOW, "Switching from V.29 + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx)); fax_modems_set_rx_handler(s, (span_rx_handler_t) &fsk_rx, &s->v21_rx, (span_rx_fillin_handler_t) &fsk_rx_fillin, &s->v21_rx); } /*endif*/ return 0; }
SPAN_DECLARE(int) fax_modems_v17_v21_rx(void *user_data, const int16_t amp[], int len) { fax_modems_state_t *s; s = (fax_modems_state_t *) user_data; v17_rx(&s->v17_rx, amp, len); fsk_rx(&s->v21_rx, amp, len); if (s->rx_frame_received) { /* We have received something, and the fast modem has not trained. We must be receiving valid V.21 */ span_log(&s->logging, SPAN_LOG_FLOW, "Switching from V.17 + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx)); s->rx_handler = (span_rx_handler_t *) &fsk_rx; s->rx_user_data = &s->v21_rx; } return 0; }
static int early_v29_rx(void *user_data, const int16_t amp[], int len) { fax_state_t *s; s = (fax_state_t *) user_data; v29_rx(&(s->v29rx), amp, len); fsk_rx(&(s->v21rx), amp, len); if (s->t30_state.rx_trained) { /* The fast modem has trained, so we no longer need to run the slow one in parallel. */ span_log(&s->logging, SPAN_LOG_FLOW, "Switching from V.29 + V.21 to V.29 (%.2fdBm0)\n", v29_rx_signal_power(&(s->v29rx))); s->rx_handler = (span_rx_handler_t *) &v29_rx; s->rx_user_data = &(s->v29rx); } return len; }
int main(int argc, char *argv[]) { fsk_tx_state_t *caller_tx; fsk_rx_state_t *caller_rx; fsk_tx_state_t *answerer_tx; fsk_rx_state_t *answerer_rx; bert_state_t caller_bert; bert_state_t answerer_bert; bert_results_t bert_results; power_meter_t caller_meter; power_meter_t answerer_meter; int16_t caller_amp[BLOCK_LEN]; int16_t answerer_amp[BLOCK_LEN]; int16_t caller_model_amp[BLOCK_LEN]; int16_t answerer_model_amp[BLOCK_LEN]; int16_t out_amp[2*BLOCK_LEN]; AFfilehandle inhandle; AFfilehandle outhandle; int outframes; int i; int j; int samples; int test_bps; int noise_level; int noise_sweep; int bits_per_test; int line_model_no; int modem_under_test_1; int modem_under_test_2; int modems_set; int log_audio; int channel_codec; int rbs_pattern; int on_at; int off_at; tone_gen_descriptor_t tone_desc; tone_gen_state_t tone_tx; int opt; channel_codec = MUNGE_CODEC_NONE; rbs_pattern = 0; line_model_no = 0; decode_test_file = NULL; noise_sweep = FALSE; modem_under_test_1 = FSK_V21CH1; modem_under_test_2 = FSK_V21CH2; log_audio = FALSE; modems_set = 0; while ((opt = getopt(argc, argv, "c:dlm:nr:s:")) != -1) { switch (opt) { case 'c': channel_codec = atoi(optarg); break; case 'd': decode_test_file = optarg; break; case 'l': log_audio = TRUE; break; case 'm': line_model_no = atoi(optarg); break; case 'n': noise_sweep = TRUE; break; case 'r': rbs_pattern = atoi(optarg); break; case 's': switch (modems_set++) { case 0: modem_under_test_1 = atoi(optarg); break; case 1: modem_under_test_2 = atoi(optarg); break; } break; default: //usage(); exit(2); break; } } if (modem_under_test_1 >= 0) printf("Modem channel 1 is '%s'\n", preset_fsk_specs[modem_under_test_1].name); if (modem_under_test_2 >= 0) printf("Modem channel 2 is '%s'\n", preset_fsk_specs[modem_under_test_2].name); outhandle = AF_NULL_FILEHANDLE; if (log_audio) { if ((outhandle = afOpenFile_telephony_write(OUTPUT_FILE_NAME, 2)) == AF_NULL_FILEHANDLE) { fprintf(stderr, " Cannot create wave file '%s'\n", OUTPUT_FILE_NAME); exit(2); } } noise_level = -200; bits_per_test = 0; inhandle = NULL; memset(caller_amp, 0, sizeof(*caller_amp)); memset(answerer_amp, 0, sizeof(*answerer_amp)); memset(caller_model_amp, 0, sizeof(*caller_model_amp)); memset(answerer_model_amp, 0, sizeof(*answerer_model_amp)); power_meter_init(&caller_meter, 7); power_meter_init(&answerer_meter, 7); if (decode_test_file) { if ((inhandle = afOpenFile_telephony_read(decode_test_file, 1)) == AF_NULL_FILEHANDLE) { fprintf(stderr, " Cannot open wave file '%s'\n", decode_test_file); exit(2); } caller_rx = fsk_rx_init(NULL, &preset_fsk_specs[modem_under_test_1], TRUE, put_bit, NULL); fsk_rx_set_modem_status_handler(caller_rx, rx_status, (void *) &caller_rx); test_bps = preset_fsk_specs[modem_under_test_1].baud_rate; for (;;) { samples = afReadFrames(inhandle, AF_DEFAULT_TRACK, caller_model_amp, BLOCK_LEN); if (samples < BLOCK_LEN) break; for (i = 0; i < samples; i++) power_meter_update(&caller_meter, caller_model_amp[i]); fsk_rx(caller_rx, caller_model_amp, samples); } if (afCloseFile(inhandle) != 0) { fprintf(stderr, " Cannot close wave file '%s'\n", decode_test_file); exit(2); } } else { printf("Test cutoff level\n"); caller_rx = fsk_rx_init(NULL, &preset_fsk_specs[modem_under_test_1], TRUE, cutoff_test_put_bit, NULL); fsk_rx_signal_cutoff(caller_rx, -30.0f); fsk_rx_set_modem_status_handler(caller_rx, cutoff_test_rx_status, (void *) &caller_rx); on_at = 0; for (i = -40; i < -25; i++) { make_tone_gen_descriptor(&tone_desc, 1500, i, 0, 0, 1, 0, 0, 0, TRUE); tone_gen_init(&tone_tx, &tone_desc); for (j = 0; j < 10; j++) { samples = tone_gen(&tone_tx, caller_model_amp, 160); fsk_rx(caller_rx, caller_model_amp, samples); } if (cutoff_test_carrier) break; } on_at = i; off_at = 0; for ( ; i > -40; i--) { make_tone_gen_descriptor(&tone_desc, 1500, i, 0, 0, 1, 0, 0, 0, TRUE); tone_gen_init(&tone_tx, &tone_desc); for (j = 0; j < 10; j++) { samples = tone_gen(&tone_tx, caller_model_amp, 160); fsk_rx(caller_rx, caller_model_amp, samples); } if (!cutoff_test_carrier) break; } off_at = i; printf("Carrier on at %d, off at %d\n", on_at, off_at); if (on_at < -29 || on_at > -26 || off_at < -35 || off_at > -31) { printf("Tests failed.\n"); exit(2); } printf("Test with BERT\n"); test_bps = preset_fsk_specs[modem_under_test_1].baud_rate; if (modem_under_test_1 >= 0) { caller_tx = fsk_tx_init(NULL, &preset_fsk_specs[modem_under_test_1], (get_bit_func_t) bert_get_bit, &caller_bert); fsk_tx_set_modem_status_handler(caller_tx, tx_status, (void *) &caller_tx); answerer_rx = fsk_rx_init(NULL, &preset_fsk_specs[modem_under_test_1], TRUE, (put_bit_func_t) bert_put_bit, &answerer_bert); fsk_rx_set_modem_status_handler(answerer_rx, rx_status, (void *) &answerer_rx); } if (modem_under_test_2 >= 0) { answerer_tx = fsk_tx_init(NULL, &preset_fsk_specs[modem_under_test_2], (get_bit_func_t) bert_get_bit, &answerer_bert); fsk_tx_set_modem_status_handler(answerer_tx, tx_status, (void *) &answerer_tx); caller_rx = fsk_rx_init(NULL, &preset_fsk_specs[modem_under_test_2], TRUE, (put_bit_func_t) bert_put_bit, &caller_bert); fsk_rx_set_modem_status_handler(caller_rx, rx_status, (void *) &caller_rx); } test_bps = preset_fsk_specs[modem_under_test_1].baud_rate; bits_per_test = 500000; noise_level = -24; bert_init(&caller_bert, bits_per_test, BERT_PATTERN_ITU_O152_11, test_bps, 20); bert_set_report(&caller_bert, 100000, reporter, (void *) (intptr_t) 1); bert_init(&answerer_bert, bits_per_test, BERT_PATTERN_ITU_O152_11, test_bps, 20); bert_set_report(&answerer_bert, 100000, reporter, (void *) (intptr_t) 2); if ((model = both_ways_line_model_init(line_model_no, (float) noise_level, line_model_no, (float) noise_level, channel_codec, rbs_pattern)) == NULL) { fprintf(stderr, " Failed to create line model\n"); exit(2); } for (;;) { samples = fsk_tx(caller_tx, caller_amp, BLOCK_LEN); for (i = 0; i < samples; i++) power_meter_update(&caller_meter, caller_amp[i]); samples = fsk_tx(answerer_tx, answerer_amp, BLOCK_LEN); for (i = 0; i < samples; i++) power_meter_update(&answerer_meter, answerer_amp[i]); both_ways_line_model(model, caller_model_amp, caller_amp, answerer_model_amp, answerer_amp, samples); //printf("Powers %10.5fdBm0 %10.5fdBm0\n", power_meter_current_dbm0(&caller_meter), power_meter_current_dbm0(&answerer_meter)); fsk_rx(answerer_rx, caller_model_amp, samples); for (i = 0; i < samples; i++) out_amp[2*i] = caller_model_amp[i]; for ( ; i < BLOCK_LEN; i++) out_amp[2*i] = 0; fsk_rx(caller_rx, answerer_model_amp, samples); for (i = 0; i < samples; i++) out_amp[2*i + 1] = answerer_model_amp[i]; for ( ; i < BLOCK_LEN; i++) out_amp[2*i + 1] = 0; if (log_audio) { outframes = afWriteFrames(outhandle, AF_DEFAULT_TRACK, out_amp, BLOCK_LEN); if (outframes != BLOCK_LEN) { fprintf(stderr, " Error writing wave file\n"); exit(2); } } if (samples < BLOCK_LEN) { bert_result(&caller_bert, &bert_results); fprintf(stderr, "%ddB AWGN, %d bits, %d bad bits, %d resyncs\n", noise_level, bert_results.total_bits, bert_results.bad_bits, bert_results.resyncs); if (!noise_sweep) { if (bert_results.total_bits != bits_per_test - 43 || bert_results.bad_bits != 0 || bert_results.resyncs != 0) { printf("Tests failed.\n"); exit(2); } } bert_result(&answerer_bert, &bert_results); fprintf(stderr, "%ddB AWGN, %d bits, %d bad bits, %d resyncs\n", noise_level, bert_results.total_bits, bert_results.bad_bits, bert_results.resyncs); if (!noise_sweep) { if (bert_results.total_bits != bits_per_test - 43 || bert_results.bad_bits != 0 || bert_results.resyncs != 0) { printf("Tests failed.\n"); exit(2); } break; } /* Put a little silence between the chunks in the file. */ memset(out_amp, 0, sizeof(out_amp)); if (log_audio) { for (i = 0; i < 200; i++) { outframes = afWriteFrames(outhandle, AF_DEFAULT_TRACK, out_amp, BLOCK_LEN); } } if (modem_under_test_1 >= 0) { caller_tx = fsk_tx_init(NULL, &preset_fsk_specs[modem_under_test_1], (get_bit_func_t) bert_get_bit, &caller_bert); fsk_tx_set_modem_status_handler(caller_tx, tx_status, (void *) &caller_tx); answerer_rx = fsk_rx_init(NULL, &preset_fsk_specs[modem_under_test_1], TRUE, (put_bit_func_t) bert_put_bit, &answerer_bert); fsk_rx_set_modem_status_handler(answerer_rx, rx_status, (void *) &answerer_rx); } if (modem_under_test_2 >= 0) { answerer_tx = fsk_tx_init(NULL, &preset_fsk_specs[modem_under_test_2], (get_bit_func_t) bert_get_bit, &answerer_bert); fsk_tx_set_modem_status_handler(answerer_tx, tx_status, (void *) &answerer_tx); caller_rx = fsk_rx_init(NULL, &preset_fsk_specs[modem_under_test_2], TRUE, (put_bit_func_t) bert_put_bit, &caller_bert); fsk_rx_set_modem_status_handler(caller_rx, rx_status, (void *) &caller_rx); } noise_level++; if ((model = both_ways_line_model_init(line_model_no, (float) noise_level, line_model_no, noise_level, channel_codec, 0)) == NULL) { fprintf(stderr, " Failed to create line model\n"); exit(2); } bert_init(&caller_bert, bits_per_test, BERT_PATTERN_ITU_O152_11, test_bps, 20); bert_set_report(&caller_bert, 100000, reporter, (void *) (intptr_t) 1); bert_init(&answerer_bert, bits_per_test, BERT_PATTERN_ITU_O152_11, test_bps, 20); bert_set_report(&answerer_bert, 100000, reporter, (void *) (intptr_t) 2); } } printf("Tests passed.\n"); } if (log_audio) { if (afCloseFile(outhandle) != 0) { fprintf(stderr, " Cannot close wave file '%s'\n", OUTPUT_FILE_NAME); exit(2); } } return 0; }
int main(int argc, char *argv[]) { fsk_rx_state_t *fsk; v17_rx_state_t *v17; v29_rx_state_t *v29; v27ter_rx_state_t *v27ter_4800; v27ter_rx_state_t *v27ter_2400; int16_t amp[SAMPLES_PER_CHUNK]; SNDFILE *inhandle; SF_INFO info; int len; const char *filename; logging_state_t *logging; filename = "fax_samp.wav"; if (argc > 1) filename = argv[1]; memset(&info, 0, sizeof(info)); if ((inhandle = sf_open(filename, SFM_READ, &info)) == NULL) { fprintf(stderr, " Cannot open audio file '%s' for reading\n", filename); exit(2); } if (info.samplerate != SAMPLE_RATE) { fprintf(stderr, " Unexpected sample rate in audio file '%s'\n", filename); exit(2); } if (info.channels != 1) { fprintf(stderr, " Unexpected number of channels in audio file '%s'\n", filename); exit(2); } memset(&t30_dummy, 0, sizeof(t30_dummy)); span_log_init(&t30_dummy.logging, SPAN_LOG_FLOW, NULL); span_log_set_protocol(&t30_dummy.logging, "T.30"); hdlc_rx_init(&hdlcrx, FALSE, TRUE, 5, hdlc_accept, NULL); fsk = fsk_rx_init(NULL, &preset_fsk_specs[FSK_V21CH2], FSK_FRAME_MODE_SYNC, v21_put_bit, NULL); v17 = v17_rx_init(NULL, 14400, v17_put_bit, NULL); v29 = v29_rx_init(NULL, 9600, v29_put_bit, NULL); //v29 = v29_rx_init(NULL, 7200, v29_put_bit, NULL); v27ter_4800 = v27ter_rx_init(NULL, 4800, v27ter_put_bit, NULL); v27ter_2400 = v27ter_rx_init(NULL, 2400, v27ter_put_bit, NULL); fsk_rx_signal_cutoff(fsk, -45.5); v17_rx_signal_cutoff(v17, -45.5); v29_rx_signal_cutoff(v29, -45.5); v27ter_rx_signal_cutoff(v27ter_4800, -40.0); v27ter_rx_signal_cutoff(v27ter_2400, -40.0); #if 1 logging = v17_rx_get_logging_state(v17); span_log_init(logging, SPAN_LOG_FLOW, NULL); span_log_set_protocol(logging, "V.17"); span_log_set_level(logging, SPAN_LOG_SHOW_SEVERITY | SPAN_LOG_SHOW_PROTOCOL | SPAN_LOG_SHOW_TAG | SPAN_LOG_FLOW); logging = v29_rx_get_logging_state(v29); span_log_init(logging, SPAN_LOG_FLOW, NULL); span_log_set_protocol(logging, "V.29"); span_log_set_level(logging, SPAN_LOG_SHOW_SEVERITY | SPAN_LOG_SHOW_PROTOCOL | SPAN_LOG_SHOW_TAG | SPAN_LOG_FLOW); logging = v27ter_rx_get_logging_state(v27ter_4800); span_log_init(logging, SPAN_LOG_FLOW, NULL); span_log_set_protocol(logging, "V.27ter-4800"); span_log_set_level(logging, SPAN_LOG_SHOW_SEVERITY | SPAN_LOG_SHOW_PROTOCOL | SPAN_LOG_SHOW_TAG | SPAN_LOG_FLOW); logging = v27ter_rx_get_logging_state(v27ter_2400); span_log_init(logging, SPAN_LOG_FLOW, NULL); span_log_set_protocol(logging, "V.27ter-2400"); span_log_set_level(logging, SPAN_LOG_SHOW_SEVERITY | SPAN_LOG_SHOW_PROTOCOL | SPAN_LOG_SHOW_TAG | SPAN_LOG_FLOW); #endif if (t4_rx_init(&t4_rx_state, "fax_decode.tif", T4_COMPRESSION_ITU_T4_2D) == NULL) { fprintf(stderr, "Failed to init\n"); exit(0); } for (;;) { len = sf_readf_short(inhandle, amp, SAMPLES_PER_CHUNK); if (len < SAMPLES_PER_CHUNK) break; fsk_rx(fsk, amp, len); v17_rx(v17, amp, len); v29_rx(v29, amp, len); v27ter_rx(v27ter_4800, amp, len); v27ter_rx(v27ter_2400, amp, len); } t4_rx_release(&t4_rx_state); if (sf_close(inhandle)) { fprintf(stderr, " Cannot close audio file '%s'\n", filename); exit(2); } return 0; }
int main(int argc, char *argv[]) { fsk_rx_state_t *fsk; v17_rx_state_t *v17; v29_rx_state_t *v29; v27ter_rx_state_t *v27ter; int16_t amp[SAMPLES_PER_CHUNK]; AFfilehandle inhandle; int len; const char *filename; float x; logging_state_t *logging; filename = "fax_samp.wav"; if (argc > 1) filename = argv[1]; if ((inhandle = afOpenFile(filename, "r", NULL)) == AF_NULL_FILEHANDLE) { fprintf(stderr, " Cannot open wave file '%s'\n", filename); exit(2); } if ((x = afGetFrameSize(inhandle, AF_DEFAULT_TRACK, 1)) != 2.0) { printf(" Unexpected frame size in speech file '%s' (%f)\n", filename, x); exit(2); } if ((x = afGetRate(inhandle, AF_DEFAULT_TRACK)) != (float) SAMPLE_RATE) { printf(" Unexpected sample rate in speech file '%s' (%f)\n", filename, x); exit(2); } if ((x = afGetChannels(inhandle, AF_DEFAULT_TRACK)) != 1.0) { printf(" Unexpected number of channels in speech file '%s' (%f)\n", filename, x); exit(2); } memset(&t30_dummy, 0, sizeof(t30_dummy)); span_log_init(&t30_dummy.logging, SPAN_LOG_FLOW, NULL); span_log_set_protocol(&t30_dummy.logging, "T.30"); hdlc_rx_init(&hdlcrx, FALSE, TRUE, 5, hdlc_accept, NULL); fsk = fsk_rx_init(NULL, &preset_fsk_specs[FSK_V21CH2], TRUE, v21_put_bit, NULL); v17 = v17_rx_init(NULL, 14400, v17_put_bit, NULL); v29 = v29_rx_init(NULL, 9600, v29_put_bit, NULL); //v29 = v29_rx_init(NULL, 7200, v29_put_bit, NULL); v27ter = v27ter_rx_init(NULL, 4800, v27ter_put_bit, NULL); fsk_rx_signal_cutoff(fsk, -45.5); v17_rx_signal_cutoff(v17, -45.5); v29_rx_signal_cutoff(v29, -45.5); v27ter_rx_signal_cutoff(v27ter, -40.0); #if 1 logging = v17_rx_get_logging_state(v17); span_log_init(logging, SPAN_LOG_FLOW, NULL); span_log_set_protocol(logging, "V.17"); span_log_set_level(logging, SPAN_LOG_SHOW_SEVERITY | SPAN_LOG_SHOW_PROTOCOL | SPAN_LOG_SHOW_TAG | SPAN_LOG_FLOW); logging = v29_rx_get_logging_state(v29); span_log_init(logging, SPAN_LOG_FLOW, NULL); span_log_set_protocol(logging, "V.29"); span_log_set_level(logging, SPAN_LOG_SHOW_SEVERITY | SPAN_LOG_SHOW_PROTOCOL | SPAN_LOG_SHOW_TAG | SPAN_LOG_FLOW); logging = v27ter_rx_get_logging_state(v27ter); span_log_init(logging, SPAN_LOG_FLOW, NULL); span_log_set_protocol(logging, "V.27ter"); span_log_set_level(logging, SPAN_LOG_SHOW_SEVERITY | SPAN_LOG_SHOW_PROTOCOL | SPAN_LOG_SHOW_TAG | SPAN_LOG_FLOW); #endif if (t4_rx_init(&t4_state, "fax_decode.tif", T4_COMPRESSION_ITU_T4_2D) == NULL) { fprintf(stderr, "Failed to init\n"); exit(0); } for (;;) { len = afReadFrames(inhandle, AF_DEFAULT_TRACK, amp, SAMPLES_PER_CHUNK); if (len < SAMPLES_PER_CHUNK) break; fsk_rx(fsk, amp, len); v17_rx(v17, amp, len); v29_rx(v29, amp, len); //v27ter_rx(v27ter, amp, len); } t4_rx_release(&t4_state); if (afCloseFile(inhandle) != 0) { fprintf(stderr, " Cannot close wave file '%s'\n", filename); exit(2); } return 0; }
SPAN_DECLARE(int) modem_connect_tones_rx(modem_connect_tones_rx_state_t *s, const int16_t amp[], int len) { int i; int16_t notched; float v1; float famp; switch (s->tone_type) { case MODEM_CONNECT_TONES_FAX_CNG: for (i = 0; i < len; i++) { /* A Cauer notch at 1100Hz, spread just wide enough to meet our detection bandwidth criteria. */ famp = amp[i]; v1 = 0.792928f*famp + 1.0018744927985f*s->z1 - 0.54196833412465f*s->z2; famp = v1 - 1.2994747954630f*s->z1 + s->z2; s->z2 = s->z1; s->z1 = v1; notched = (int16_t) lfastrintf(famp); /* Estimate the overall energy in the channel, and the energy in the notch (i.e. overall channel energy - tone energy => noise). Use abs instead of multiply for speed (is it really faster?). */ s->channel_level += ((abs(amp[i]) - s->channel_level) >> 5); s->notch_level += ((abs(notched) - s->notch_level) >> 5); if (s->channel_level > 70 && s->notch_level*6 < s->channel_level) { /* There is adequate energy in the channel, and it is mostly at 1100Hz. */ if (s->tone_present != MODEM_CONNECT_TONES_FAX_CNG) { if (++s->tone_cycle_duration >= ms_to_samples(415)) report_tone_state(s, MODEM_CONNECT_TONES_FAX_CNG, lfastrintf(log10f(s->channel_level/32768.0f)*20.0f + DBM0_MAX_POWER + 0.8f)); } } else { /* If the signal looks wrong, even for a moment, we consider this the end of the tone. */ if (s->tone_present == MODEM_CONNECT_TONES_FAX_CNG) report_tone_state(s, MODEM_CONNECT_TONES_NONE, -99); s->tone_cycle_duration = 0; } } break; case MODEM_CONNECT_TONES_FAX_CED_OR_PREAMBLE: /* Also look for V.21 preamble. A lot of machines don't send the 2100Hz burst. It might also not be seen all the way through the channel, due to switching delays. */ fsk_rx(&(s->v21rx), amp, len); /* Now fall through and look for a 2100Hz tone */ case MODEM_CONNECT_TONES_ANS: for (i = 0; i < len; i++) { /* A Cauer notch at 2100Hz, spread just wide enough to meet our detection bandwidth criteria. */ /* This is actually centred at 2095Hz, but gets the balance we want, due to the asymmetric walls of the notch */ famp = amp[i]; v1 = 0.76000f*famp - 0.1183852f*s->z1 - 0.5104039f*s->z2; famp = v1 + 0.1567596f*s->z1 + s->z2; s->z2 = s->z1; s->z1 = v1; notched = (int16_t) lfastrintf(famp); /* Estimate the overall energy in the channel, and the energy in the notch (i.e. overall channel energy - tone energy => noise). Use abs instead of multiply for speed (is it really faster?). Damp the overall energy a little more for a stable result. Damp the notch energy a little less, so we don't damp out the blip every time the phase reverses */ s->channel_level += ((abs(amp[i]) - s->channel_level) >> 5); s->notch_level += ((abs(notched) - s->notch_level) >> 4); /* This should cut off at about -43dBm0 */ if (s->channel_level <= 70) { /* If the energy level is low, even for a moment, we consider this the end of the tone. */ if (s->tone_present != MODEM_CONNECT_TONES_NONE) report_tone_state(s, MODEM_CONNECT_TONES_NONE, -99); s->tone_cycle_duration = 0; s->good_cycles = 0; s->tone_on = FALSE; continue; } /* There is adequate energy in the channel. Is it mostly at 2100Hz? */ s->tone_cycle_duration++; if (s->notch_level*6 < s->channel_level) { /* The notch test says yes, so we have the tone. */ /* We should get a kick from the notch filter every 450+-25ms, as the phase reverses, for an EC disable tone. For a simple answer tone, the tone should persist unbroken for longer. */ if (!s->tone_on) { if (s->tone_cycle_duration >= ms_to_samples(450 - 25)) { if (++s->good_cycles == 3) report_tone_state(s, MODEM_CONNECT_TONES_ANS_PR, lfastrintf(log10f(s->channel_level/32768.0f)*20.0f + DBM0_MAX_POWER + 0.8f)); } else { s->good_cycles = 0; } /* Cycles are timed from rising edge to rising edge */ s->tone_cycle_duration = 0; } else { if (s->tone_cycle_duration >= ms_to_samples(550)) { if (s->tone_present == MODEM_CONNECT_TONES_NONE) report_tone_state(s, MODEM_CONNECT_TONES_ANS, lfastrintf(log10f(s->channel_level/32768.0f)*20.0f + DBM0_MAX_POWER + 0.8f)); s->good_cycles = 0; s->tone_cycle_duration = ms_to_samples(550); } } s->tone_on = TRUE; } else { if (s->tone_present == MODEM_CONNECT_TONES_ANS) { report_tone_state(s, MODEM_CONNECT_TONES_NONE, -99); s->good_cycles = 0; } else { if (s->tone_cycle_duration >= ms_to_samples(450 + 25)) { /* The change came too late for a cycle of ANS_PR tone */ if (s->tone_present == MODEM_CONNECT_TONES_ANS_PR || s->tone_present == MODEM_CONNECT_TONES_ANSAM_PR) report_tone_state(s, MODEM_CONNECT_TONES_NONE, -99); s->good_cycles = 0; } } s->tone_on = FALSE; } } break; } return 0; }