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mirror of https://github.com/radio95-rnt/fm95.git synced 2026-02-26 19:23:51 +01:00
This commit is contained in:
2025-03-27 18:23:22 +01:00
parent 531e5a6a38
commit abc6922852

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@@ -38,7 +38,21 @@ void init_lpf4(LPF4* filter, float sample_rate, float cutoff_freq) {
float Q2 = 1.0f / (2.0f * cosf(3.0f * M_PI / 8.0f));
init_lpf(&filter->section2, sample_rate, cutoff_freq, Q2);
}
float biquad(Biquad *filter, float input) {
float output = filter->b0 * input
+ filter->b1 * filter->x1
+ filter->b2 * filter->x2
- filter->a1 * filter->y1
- filter->a2 * filter->y2;
filter->x2 = filter->x1;
filter->x1 = input;
filter->y2 = filter->y1;
filter->y1 = output;
return output;
}
float apply_lpf4(LPF4* filter, float input) {
float output = biquad(&filter->section1, input);
output = biquad(&filter->section2, output);