113 lines
2.6 KiB
C
113 lines
2.6 KiB
C
#include <stdio.h>
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#include <stdint.h>
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#include <math.h>
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#include <string.h>
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#include "../libsample/sample.h"
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#include "../libfilter/iir_filter.h"
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#include "../libdebug/debug.h"
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#define level2db(level) (20 * log10(level))
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#define db2level(db) pow(10, (double)db / 20.0)
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#define SAMPLERATE 48000
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static double get_level(sample_t *samples)
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{
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int i;
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double envelope = 0;
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for (i = SAMPLERATE/2; i < SAMPLERATE; i++) {
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if (samples[i] > envelope)
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envelope = samples[i];
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}
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return envelope;
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}
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static void gen_samples(sample_t *samples, double freq)
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{
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int i;
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double value;
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for (i = 0; i < SAMPLERATE; i++) {
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value = cos(2.0 * M_PI * freq / (double)SAMPLERATE * (double)i);
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samples[i] = value;
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}
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}
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extern void main_mobile();
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int main(void)
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{
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iir_filter_t filter_low;
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iir_filter_t filter_high;
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sample_t samples[SAMPLERATE];
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double level;
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int iter = 2;
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int i;
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/* this is never called, it forces the linker to add mobile functions */
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if (debuglevel == -1000) main_mobile();
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debuglevel = DEBUG_DEBUG;
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printf("testing low-pass filter with %d iterations\n", iter);
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iir_lowpass_init(&filter_low, 1000.0, SAMPLERATE, iter);
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for (i = 0; i < 4001; i += 100) {
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gen_samples(samples, (double)i);
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iir_process(&filter_low, samples, SAMPLERATE);
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level = get_level(samples);
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printf("%s%4d Hz: %.1f dB", debug_db(level), i, level2db(level));
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if (i == 1000)
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printf(" cutoff\n");
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else if (i == 2000)
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printf(" double frequency\n");
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else if (i == 4000)
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printf(" quad frequency\n");
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else
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printf("\n");
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}
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printf("testing high-pass filter with %d iterations\n", iter);
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iir_highpass_init(&filter_high, 2000.0, SAMPLERATE, iter);
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for (i = 0; i < 4001; i += 100) {
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gen_samples(samples, (double)i);
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iir_process(&filter_high, samples, SAMPLERATE);
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level = get_level(samples);
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printf("%s%4d Hz: %.1f dB", debug_db(level), i, level2db(level));
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if (i == 2000)
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printf(" cutoff\n");
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else if (i == 1000)
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printf(" half frequency\n");
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else if (i == 500)
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printf(" quarter frequency\n");
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else
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printf("\n");
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}
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printf("testing band-pass filter with %d iterations\n", iter);
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iir_lowpass_init(&filter_low, 2000.0, SAMPLERATE, iter);
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iir_highpass_init(&filter_high, 1000.0, SAMPLERATE, iter);
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for (i = 0; i < 4001; i += 100) {
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gen_samples(samples, (double)i);
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iir_process(&filter_low, samples, SAMPLERATE);
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iir_process(&filter_high, samples, SAMPLERATE);
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level = get_level(samples);
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printf("%s%4d Hz: %.1f dB", debug_db(level), i, level2db(level));
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if (i == 1000)
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printf(" cutoff high\n");
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else if (i == 2000)
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printf(" cutoff low\n");
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else
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printf("\n");
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}
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return 0;
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}
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