diff options
| -rw-r--r-- | util/spkmodem_decode/spkmodem-decode.c | 57 |
1 files changed, 51 insertions, 6 deletions
diff --git a/util/spkmodem_decode/spkmodem-decode.c b/util/spkmodem_decode/spkmodem-decode.c index 3c4b94c1..f08b1b52 100644 --- a/util/spkmodem_decode/spkmodem-decode.c +++ b/util/spkmodem_decode/spkmodem-decode.c @@ -128,6 +128,9 @@ #define SEP_TONE_MIN_HZ 1000 #define SEP_TONE_MAX_HZ 3000 +#define SEP_TOLERANCE_PULSES \ + (((SEP_TONE_MAX_HZ) - (SEP_TONE_MIN_HZ)) / (2 * (FRAME_RATE))) + #define DATA_TONE_MIN_HZ 3000 #define DATA_TONE_MAX_HZ 12000 @@ -180,6 +183,12 @@ struct decoder_state { int debug; int swap_bytes; + + /* dynamic separator calibration */ + int sep_sum; + int sep_samples; + int sep_min; + int sep_max; }; static const char *argv0; @@ -228,6 +237,12 @@ main(int argc, char **argv) break; } + /* + * Used for separator calibration + */ + st.sep_min = FREQ_SEP_MIN; + st.sep_max = FREQ_SEP_MAX; + st.ascii_bit = 7; st.ringpos = 0; @@ -254,6 +269,7 @@ host_is_big_endian(void) static void handle_audio(struct decoder_state *st) { + int avg; int sample; /* @@ -262,7 +278,30 @@ handle_audio(struct decoder_state *st) */ if (st->sample_count >= (3 * SAMPLES_PER_FRAME)) reset_char(st); + if (!valid_signal(st)) { + + /* + * collect separator tone statistics + * (and auto-adjust tolerances) + */ + if (st->sep_samples < 50 && st->freq_separator > 0) { + st->sep_sum += st->freq_separator; + st->sep_samples++; + + if (st->sep_samples == 50) { + avg = st->sep_sum / st->sep_samples; + + /* ±3 pulse window */ + st->sep_min = avg - SEP_TOLERANCE_PULSES; + st->sep_max = avg + SEP_TOLERANCE_PULSES; + + if (st->debug) + printf("separator calibrated: %dHz\n", + avg * FRAME_RATE); + } + } + decode_pulse(st); return; } @@ -283,8 +322,8 @@ handle_audio(struct decoder_state *st) static int valid_signal(struct decoder_state *st) { - return (st->freq_separator > FREQ_SEP_MIN && - st->freq_separator < FREQ_SEP_MAX && + return (st->freq_separator > st->sep_min && + st->freq_separator < st->sep_max && st->freq_data > FREQ_DATA_MIN && st->freq_data < FREQ_DATA_MAX); } @@ -438,24 +477,30 @@ print_stats(struct decoder_state *st) int data_hz = st->freq_data * FRAME_RATE; int sep_hz = st->freq_separator * FRAME_RATE; + int sep_hz_min = st->sep_min * FRAME_RATE; + int sep_hz_max = st->sep_max * FRAME_RATE; if ((pos = ftell(stdin)) == -1) { - printf("%d %d %d data=%dHz sep=%dHz\n", + printf("%d %d %d data=%dHz sep=%dHz(min %dHz %dHz)\n", st->freq_data, st->freq_separator, FREQ_DATA_THRESHOLD, data_hz, - sep_hz); + sep_hz, + sep_hz_min, + sep_hz_max); return; } - printf("%d %d %d @%ld data=%dHz sep=%dHz\n", + printf("%d %d %d @%ld data=%dHz sep=%dHz(min %dHz %dHz)\n", st->freq_data, st->freq_separator, FREQ_DATA_THRESHOLD, pos - SAMPLE_OFFSET, data_hz, - sep_hz); + sep_hz, + sep_hz_min, + sep_hz_max); } static void |