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Implementation of RX level squelch (for A-Netz and B-Netz)

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Use -S <dB> for setting RF level or use -S auto for auto level.

When squelch closes, audio is muted. If squelch is closed for some
seconds (depending on network), call is released. (RF loss condition)

The previous loss detection has been removed
This commit is contained in:
Andreas Eversberg
2017-10-09 20:49:14 +02:00
parent f7a0e4622b
commit b32e0ab602
33 changed files with 310 additions and 263 deletions
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32
src/anetz/dsp.c
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@@ -49,8 +49,8 @@
#define TONE_DETECT_TH 8 /* chunk intervals to detect continuous tone */
/* carrier loss detection */
#define LOSS_INTERVAL 100 /* filter steps (chunk durations) for one second interval */
#define LOSS_TIME 12 /* duration of signal loss before release */
#define MUTE_TIME 0.1 /* time to mute after loosing signal */
#define LOSS_TIME 12.0 /* duration of signal loss before release (what was the actual duration ???) */
/* two signaling tones */
static double fsk_tones[2] = {
@@ -77,7 +77,7 @@ void dsp_init(void)
}
/* Init transceiver instance. */
int dsp_init_sender(anetz_t *anetz, double page_gain, int page_sequence)
int dsp_init_sender(anetz_t *anetz, double page_gain, int page_sequence, double squelch_db)
{
sample_t *spl;
int i;
@@ -85,14 +85,15 @@ int dsp_init_sender(anetz_t *anetz, double page_gain, int page_sequence)
PDEBUG_CHAN(DDSP, DEBUG_DEBUG, "Init DSP for 'Sender'.\n");
/* init squelch */
squelch_init(&anetz->squelch, anetz->sender.kanal, squelch_db, MUTE_TIME, LOSS_TIME);
/* set modulation parameters */
sender_set_fm(&anetz->sender, MAX_DEVIATION * page_gain, MAX_MODULATION, DBM0_DEVIATION, MAX_DISPLAY);
anetz->page_gain = page_gain;
anetz->page_sequence = page_sequence;
audio_init_loss(&anetz->sender.loss, LOSS_INTERVAL, anetz->sender.loss_volume, LOSS_TIME);
anetz->samples_per_chunk = anetz->sender.samplerate * CHUNK_DURATION;
PDEBUG(DDSP, DEBUG_DEBUG, "Using %d samples per chunk duration.\n", anetz->samples_per_chunk);
spl = calloc(anetz->samples_per_chunk, sizeof(sample_t));
@@ -147,24 +148,19 @@ static void fsk_receive_tone(anetz_t *anetz, int tone, int goodtone, double leve
anetz->tone_count++;
if (anetz->tone_count >= TONE_DETECT_TH)
audio_reset_loss(&anetz->sender.loss);
if (anetz->tone_count == TONE_DETECT_TH) {
PDEBUG_CHAN(DDSP, DEBUG_INFO, "Detecting continuous %.0f Hz tone. (level = %.0f%%, quality =%.0f%%)\n", fsk_tones[anetz->tone_detected], level * 100.0, quality * 100.0);
anetz_receive_tone(anetz, anetz->tone_detected);
}
}
/* Filter one chunk of audio an detect tone, quality and loss of signal. */
/* Filter one chunk of audio an detect tone and quality of signal. */
static void fsk_decode_chunk(anetz_t *anetz, sample_t *spl, int max)
{
double level, result[2], quality[2];
level = audio_level(spl, max);
if (audio_detect_loss(&anetz->sender.loss, level))
anetz_loss_indication(anetz);
audio_goertzel(anetz->fsk_tone_goertzel, spl, max, 0, result, 2);
/* normalize quality of tones and level */
@@ -189,13 +185,25 @@ static void fsk_decode_chunk(anetz_t *anetz, sample_t *spl, int max)
}
/* Process received audio stream from radio unit. */
void sender_receive(sender_t *sender, sample_t *samples, int length)
void sender_receive(sender_t *sender, sample_t *samples, int length, double rf_level_db)
{
anetz_t *anetz = (anetz_t *) sender;
sample_t *spl;
int max, pos;
int i;
/* process signal mute/loss, also for signalling tone */
switch (squelch(&anetz->squelch, rf_level_db, (double)length / (double)anetz->sender.samplerate)) {
case SQUELCH_LOSS:
anetz_loss_indication(anetz, LOSS_TIME);
// fall through:
case SQUELCH_MUTE:
memset(samples, 0, sizeof(*samples) * length);
break;
default:
break;
}
/* write received samples to decode buffer */
max = anetz->samples_per_chunk;
pos = anetz->fsk_filter_pos;