radio95/fm95
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im a genius

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This commit is contained in:
KubaPro010
2025-03-25 17:10:15 +01:00
parent ae7cdcfe96
commit fab44bcc42
3 changed files with 5 additions and 22 deletions
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16
lib/filters.c
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@@ -18,22 +18,6 @@ float sincf(float x) {
return (x == 0.0f) ? 1.0f : sinf(M_PI * x) / (M_PI * x);
}
void init_bpf(FIRFilter *bpf, float start, float end) {
int m = FILTER_LEN - 1;
float sum = 0.0f;
for(int n = 0; n < FILTER_LEN; n++) {
float x = n-m/2.0f;
float h1 = sincf(2.0f*start*x) * (0.54 - 0.46 * cosf(M_2PI * n / m));
float h2 = sincf(2.0f*end*x) * (0.54 - 0.46 * cosf(M_2PI * n / m));
bpf->filter[n] = h1-h2;
sum += bpf->filter[n];
}
for(int n = 0; n < FILTER_LEN; n++) {
bpf->filter[n] /= sum;
}
}
void init_lpf(FIRFilter *lpf, float freq) {
int m = FILTER_LEN - 1;
float sum = 0.0f;

1
lib/filters.h
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@@ -23,6 +23,5 @@ typedef struct filters
float filter[FILTER_LEN];
int filter_idx;
} FIRFilter;
void init_bpf(FIRFilter *bpf, float start, float end);
void init_lpf(FIRFilter *lpf, float freq);
float fir_filter(FIRFilter *fir, float sample);