34 lines
932 B
C
34 lines
932 B
C
#include <math.h>
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#include "filter.h"
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#include "psyn.h"
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void filter_init_rc(struct filter_t *filter, double R, double C)
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{
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filter->k = 1.0 / (R * C) / _sample_rate;
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filter->r = 1.0;
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}
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void filter_init_freq(struct filter_t *filter, double freq)
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{
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filter->k = (2.0 * M_PI * freq) / _sample_rate;
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filter->r = 1.0;
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}
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void filter_run_lp(struct filter_t *filter, double left, double right)
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{
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filter->v_l += filter->k * (left - filter->last_out_l);
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filter->v_r += filter->k * (right - filter->last_out_r);
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filter->last_out_l = filter->v_l;
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filter->last_out_r = filter->v_r;
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filter->v_l *= filter->r;
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filter->v_r *= filter->r;
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}
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void filter_run_hp(struct filter_t *filter, double left, double right)
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{
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filter->last_out_l = filter->k * (filter->last_out_l + left - filter->last_in_l);
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filter->last_out_r = filter->k * (filter->last_out_r + right - filter->last_in_r);
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filter->last_in_l = left;
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filter->last_in_r = right;
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}
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