diff options
| author | Andreas Eversberg <jolly@eversberg.eu> | 2017-12-05 10:55:13 +0100 |
|---|---|---|
| committer | Andreas Eversberg <jolly@eversberg.eu> | 2017-12-09 20:46:16 +0100 |
| commit | f2eb6b3e705e4e516e7a7a3947b05a7c72ab6c8a (patch) | |
| tree | 2a062c4364d35411af4b2607604797c9dbf2b541 | |
| parent | 9f901384deda96a7dd021923841885ec1e4f2d67 (diff) | |
Squelch improvement
Continuously calculate noise floor and lower threshold level if less noise
was received. High noise or ongoing transmission during start of program will
not cause a threshold that is too far above the actual noise floor.
| -rw-r--r-- | src/libsquelch/squelch.c | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/src/libsquelch/squelch.c b/src/libsquelch/squelch.c index 4edb84e..cd6afa3 100644 --- a/src/libsquelch/squelch.c +++ b/src/libsquelch/squelch.c @@ -44,9 +44,9 @@ */ /* NOTE: SQUELCH must be calibrated !AFTER! DC bias, to get the actual noise floor */ -#define SQUELCH_INIT_TIME 1.1 /* wait some time before performing squelch */ -#define SQUELCH_AUTO_TIME 1.0 /* duration of squelch quelch calibration */ -#define SQUELCH_AUTO_OFFSET 6.0 /* auto calibration: offset above noise floor */ +#define SQUELCH_INIT_TIME 0.1 /* wait some time before performing squelch */ +#define SQUELCH_AUTO_TIME 0.5 /* duration of squelch quelch calibration */ +#define SQUELCH_AUTO_OFFSET 10.0 /* auto calibration: offset above noise floor */ void squelch_init(squelch_t *squelch, int chan, double threshold_db, double mute_time, double loss_time) { @@ -89,12 +89,19 @@ enum squelch_result squelch(squelch_t *squelch, double rf_level_db, double durat squelch->auto_count += duration; squelch->auto_level_sum += rf_level_db; squelch->auto_level_count++; - if (squelch->auto_count < SQUELCH_AUTO_TIME) - return SQUELCH_MUTE; - squelch->threshold_db = squelch->auto_level_sum / (double) squelch->auto_level_count; - PDEBUG_CHAN(DDSP, DEBUG_INFO, "RF signal measurement: %.1f dB noise floor, using threshold of %.1f dB\n", squelch->threshold_db, squelch->threshold_db + SQUELCH_AUTO_OFFSET); - squelch->threshold_db += SQUELCH_AUTO_OFFSET; - squelch->auto_state = 0; + if (squelch->auto_count >= SQUELCH_AUTO_TIME) { + double noise_db, threshold_db; + noise_db = squelch->auto_level_sum / (double) squelch->auto_level_count; + threshold_db = noise_db + SQUELCH_AUTO_OFFSET; + /* must be 0.1 dB smaller, so we prevent repeated debugging message with similar value */ + if (threshold_db < squelch->threshold_db - 0.1) { + squelch->threshold_db = threshold_db; + PDEBUG_CHAN(DDSP, DEBUG_INFO, "RF signal measurement: %.1f dB noise floor, using squelch threshold of %.1f dB\n", noise_db, threshold_db); + } + squelch->auto_count = 0.0; + squelch->auto_level_count = 0; + squelch->auto_level_sum = 0.0; + } } /* enough RF level, so we unmute when mute_count reched 0 */ |