FMTools

lib/filters.h

@@ -0,0 +1,23 @@
+#include "math.h"
+#include <string.h>
+#include "constants.h"
+
+#define FIR_PHASES 32
+#define FIR_TAPS 32
+
+typedef struct {
+    float alpha;
+    float prev_sample;
+} Emphasis;
+
+void init_emphasis(Emphasis *pe, float tau, float sample_rate);
+float apply_pre_emphasis(Emphasis *pe, float sample);
+
+typedef struct {
+    float low_pass_fir[FIR_PHASES][FIR_TAPS];
+    float sample_buffer[FIR_TAPS];
+    int buffer_index;
+} LowPassFilter;
+
+void init_low_pass_filter(LowPassFilter *lp, float cutoff_frequency, float sample_rate);
+float apply_low_pass_filter(LowPassFilter *lp, float sample);