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fm95/lib/filters.h
2025-03-27 21:36:44 +01:00

27 lines
531 B
C

#pragma once
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include "constants.h"
#include "optimization.h"
#include "oscillator.h"
#if USE_NEON
#define LPF_ORDER 20 // neon has to have divisable by 4
#else
#define LPF_ORDER 10
#endif
typedef struct
{
float alpha;
float prev_sample;
float gain;
} ResistorCapacitor;
void init_preemphasis(ResistorCapacitor *filter, float tau, float sample_rate);
float apply_preemphasis(ResistorCapacitor *filter, float sample);
float hard_clip(float sample, float threshold);