diff options
| author | Andreas Eversberg <jolly@eversberg.eu> | 2016-04-25 18:14:04 +0200 |
|---|---|---|
| committer | Andreas Eversberg <jolly@eversberg.eu> | 2016-05-01 15:14:57 +0200 |
| commit | 0c99848120f654538334491cc1abe450b831f3f0 (patch) | |
| tree | 587f6f360971663fbc2d3ce332de7f2ab629ebdd | |
| parent | 16acdbf59d8b56f759efad3ad86c75b7e472b4cd (diff) | |
common code: Make preemphasis 0 dB @ 1000 Hz
| -rw-r--r-- | src/common/emphasis.c | 6 | ||||
| -rw-r--r-- | src/test/test_emphasis.c | 2 |
2 files changed, 5 insertions, 3 deletions
diff --git a/src/common/emphasis.c b/src/common/emphasis.c index cdd4458..ccacd1f 100644 --- a/src/common/emphasis.c +++ b/src/common/emphasis.c @@ -35,11 +35,11 @@ int init_emphasis(emphasis_t *state, int samplerate) return -1; } - factor = 0.95; + factor = 0.97; state->p.factor = factor; - state->p.amp = samplerate / 48000.0 * 4.0; /* mysterious 48000 */ + state->p.amp = samplerate / 6350.0; state->d.factor = factor; - state->d.amp = 1.0 / (samplerate / 48000.0 * 4.0); /* mysterious 48000 */ + state->d.amp = 1.0 / (samplerate / 6350.0); return 0; } diff --git a/src/test/test_emphasis.c b/src/test/test_emphasis.c index b93d0c3..dc95023 100644 --- a/src/test/test_emphasis.c +++ b/src/test/test_emphasis.c @@ -52,6 +52,8 @@ int main(void) emphasis_t estate; int16_t samples[SAMPLERATE]; + printf("1000 Hz shall be close to 0 dB, that is no significant change in volume.\n\n"); + /* generate sweep 0..4khz */ gen_samples(samples); |