radio95/fm95
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correct the fm mod

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This commit is contained in:
KubaPro010
2025-03-10 21:44:42 +01:00
parent 67fe502183
commit b3303abded
3 changed files with 3 additions and 24 deletions
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18
lib/filters.c
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@@ -13,20 +13,4 @@ float apply_preemphasis(ResistorCapacitor *filter, float sample) {
float hard_clip(float sample, float threshold) { float hard_clip(float sample, float threshold) {
// Branchless clipping // Branchless clipping
return fmaxf(-threshold, fminf(threshold, sample)); return fmaxf(-threshold, fminf(threshold, sample));
} }
float voltage_db_to_voltage(float db) {
return powf(10.0f, db / 20.0f);
}
float power_db_to_voltage(float db) {
return powf(10.0f, db / 10.0f);
}
float voltage_to_voltage_db(float linear) {
return 20.0f * log10f(fmaxf(linear, 1e-10f)); // Avoid log(0)
}
float voltage_to_power_db(float linear) {
return 10.0f * log10f(fmaxf(linear, 1e-10f)); // Avoid log(0)
}

7
lib/filters.h
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@@ -1,5 +1,4 @@
#pragma once #pragma once
#define FILTER_TAPS 256
#include <math.h> #include <math.h>
#include <string.h> #include <string.h>
#include <stdlib.h> #include <stdlib.h>
@@ -14,8 +13,4 @@ typedef struct
void init_preemphasis(ResistorCapacitor *filter, float tau, float sample_rate); void init_preemphasis(ResistorCapacitor *filter, float tau, float sample_rate);
float apply_preemphasis(ResistorCapacitor *filter, float sample); float apply_preemphasis(ResistorCapacitor *filter, float sample);
float hard_clip(float sample, float threshold); float hard_clip(float sample, float threshold);
float voltage_db_to_voltage(float db);
float power_db_to_voltage(float db);
float voltage_to_voltage_db(float linear);
float voltage_to_power_db(float linear);

2
lib/fm_modulator.c
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@@ -11,6 +11,6 @@ float modulate_fm(FMModulator *fm, float sample) {
float inst_freq = fm->frequency+(sample*fm->deviation); float inst_freq = fm->frequency+(sample*fm->deviation);
if (inst_freq < 0.0f) inst_freq = 0.0f; if (inst_freq < 0.0f) inst_freq = 0.0f;
float out = sinf(fm->osc_phase); float out = sinf(fm->osc_phase);
fm->osc_phase += fmodf(fm->osc_phase + ((M_2PI * inst_freq) / fm->sample_rate), M_2PI); fm->osc_phase = fmodf(fm->osc_phase + ((M_2PI * inst_freq) / fm->sample_rate), M_2PI);
return out; return out;
} }