diff options
Diffstat (limited to 'util')
| -rw-r--r-- | util/spkmodem_decode/spkmodem-decode.c | 27 |
1 files changed, 21 insertions, 6 deletions
diff --git a/util/spkmodem_decode/spkmodem-decode.c b/util/spkmodem_decode/spkmodem-decode.c index 26b236f6..e5c0afd0 100644 --- a/util/spkmodem_decode/spkmodem-decode.c +++ b/util/spkmodem_decode/spkmodem-decode.c @@ -451,15 +451,30 @@ decode_pulse(struct decoder_state *st) static void auto_detect_tone(struct decoder_state *st) { + int f; + + /* + * Don't also run auto-detect during decode, + * otherwise it would run for every sample. + */ if (st->learn_samples >= LEARN_SAMPLES) return; - if (st->freq_data > 0) { - if (st->freq_data < st->freq_min) - st->freq_min = st->freq_data; - - if (st->freq_data > st->freq_max) - st->freq_max = st->freq_data; + /* + * Check both FIR windows. + * Inside separator frames, the separator window contains tone, + * during data frames the data window does; a minimum of + * the two captures the lowest active tone cluster more reliably. + */ + f = st->freq_data; + if (st->freq_separator > 0 && st->freq_separator < f) + f = st->freq_separator; + if (f > 0) { + if (f < st->freq_min) + st->freq_min = f; + + if (f > st->freq_max) + st->freq_max = f; } st->learn_samples++; |