radio95/fm95
0
1
Fork 0
mirror of https://github.com/radio95-rnt/fm95.git synced 2026-02-26 19:23:51 +01:00
Code Issues Activity

idk

Browse Source
This commit is contained in:
KubaPro010
2025-03-27 18:43:49 +01:00
parent 04b6935519
commit 34071c1967
2 changed files with 9 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
lib/filters.c
View File

@@ -18,23 +18,24 @@ float hard_clip(float sample, float threshold) {
void init_lpf(FIR *filter, float cutoff, int sample_rate) {
float a = tanf(M_PI*cutoff/sample_rate);
float a2 = a*a;
float r;
float r, e;
for(int i = 0; i < FIR_ORDER; i++) {
r = sinf(M_PI*(2.0f*i+1.0f)/(4.0f*FIR_ORDER));
sample_rate = a2+2.0f*a*r+1.0f;
filter->A[i] = a2 / sample_rate;
filter->d1[i] = 2.0f*(1.0f-a2)/sample_rate;
filter->d2[i] = -(a2 - 2.0f * a * r + 1.0f) / sample_rate;
e = a2+2.0f*a*r+1.0f;
filter->A[i] = a2 / e;
filter->d1[i] = 2.0f*(1.0f-a2)/e;
filter->d2[i] = -(a2 - 2.0f * a * r + 1.0f) / e;
}
}
float process_lpf(FIR *filter, float x) {
float output;
for(int i = 0; i < FIR_ORDER; i++) {
filter->w0[i] = filter->d1[i]*filter->w1[i] + filter->d2[i]*filter->w2[i] + x;
x = filter->A[i] * (filter->w0[i] + 2.0f * filter->w1[i] + filter->w2[i]);
output = filter->A[i] * (filter->w0[i] + 2.0f * filter->w1[i] + filter->w2[i]);
filter->w2[i] = filter->w1[i];
filter->w1[i] = filter->w0[i];
}
return x;
return output;
}

2
lib/filters.h
View File

@@ -5,7 +5,7 @@
#include "constants.h"
#include "oscillator.h"
#define FIR_ORDER 10
#define FIR_ORDER 21
typedef struct
{