radio95/fm95
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Code Issues Activity

get rid of lpf as it barely works, swh-plugin's lowpass_iir_1891 works better

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KubaPro010
2025-03-09 09:35:10 +01:00
parent 2c18edc6a8
commit 0a99e3364c
4 changed files with 3 additions and 46 deletions
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17
src/fm95.c
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@@ -40,8 +40,6 @@
#define MPX_VOLUME 1.0f // Passtrough
#define MPX_CLIPPER_THRESHOLD 1.0f
#define LPF_CUTOFF 15000 // Should't need to be changed
volatile sig_atomic_t to_run = 1;
void uninterleave(const float *input, float *left, float *right, size_t num_samples) {
@@ -368,13 +366,6 @@ int main(int argc, char **argv) {
ResistorCapacitor preemp_l, preemp_r;
init_preemphasis(&preemp_l, preemphasis_tau, SAMPLE_RATE);
init_preemphasis(&preemp_r, preemphasis_tau, SAMPLE_RATE);
// Use https://www.earlevel.com/main/2021/09/02/biquad-calculator-v3/
BiquadFilter lpf_l1, lpf_r1, lpf_l2, lpf_r2;
init_lpf(&lpf_l1, LPF_CUTOFF, 0.70710678f, SAMPLE_RATE);
init_lpf(&lpf_r1, LPF_CUTOFF, 0.70710678f, SAMPLE_RATE);
init_lpf(&lpf_l2, LPF_CUTOFF, 0.70710678f/2.0f, SAMPLE_RATE);
init_lpf(&lpf_r2, LPF_CUTOFF, 0.70710678f/2.0f, SAMPLE_RATE);
// #endregion
signal(SIGINT, stop);
@@ -415,12 +406,8 @@ int main(int argc, char **argv) {
float current_mpx_in = mpx_in[i];
float current_sca_in = sca_in[i];
float ready_l = apply_biquad(&lpf_l1, l_in);
float ready_r = apply_biquad(&lpf_r1, r_in);
ready_l = apply_biquad(&lpf_l2, ready_l);
ready_r = apply_biquad(&lpf_r2, ready_r);
ready_l = apply_preemphasis(&preemp_l, ready_l)*2;
ready_r = apply_preemphasis(&preemp_r, ready_r)*2;
float ready_l = apply_preemphasis(&preemp_l, l_in)*2;
float ready_r = apply_preemphasis(&preemp_r, r_in)*2;
ready_l = hard_clip(ready_l*audio_volume, clipper_threshold);
ready_r = hard_clip(ready_r*audio_volume, clipper_threshold);