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33 lines
696 B
C
33 lines
696 B
C
#pragma once
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#include <string.h>
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#include <stdlib.h>
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#include <math.h>
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#include "constants.h"
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#include "oscillator.h"
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#define LPF_ORDER 10
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typedef struct
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{
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float alpha;
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float prev_sample;
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float gain;
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} ResistorCapacitor;
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void init_preemphasis(ResistorCapacitor *filter, float tau, float sample_rate);
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float apply_preemphasis(ResistorCapacitor *filter, float sample);
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float hard_clip(float sample, float threshold);
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typedef struct
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{
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float A[LPF_ORDER];
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float d1[LPF_ORDER];
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float d2[LPF_ORDER];
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float w0[LPF_ORDER];
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float w1[LPF_ORDER];
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float w2[LPF_ORDER];
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} LPFFilter;
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void init_lpf(LPFFilter *filter, float cutoff, int sample_rate);
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float process_lpf(LPFFilter *filter, float x);
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