68 lines
1.8 KiB
C
68 lines
1.8 KiB
C
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#include <stdlib.h>
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#include <liquid/liquid.h>
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#include <math.h>
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#include <complex.h>
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#include <stdio.h>
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const float SAMPLINGRATE = 1000000.0;
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const float FFT_LEN = 256;
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int main() {
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FILE* output = fopen("output.csv", "w");
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FILE* input = fopen("input.raw", "r");
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float complex * fft_in = (float complex*) malloc(FFT_LEN * sizeof(float complex));
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float complex * fft_out = (float complex*) malloc(FFT_LEN * sizeof(float complex));
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// create FFT plan
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fftplan fft = fft_create_plan(FFT_LEN, fft_in, fft_out, LIQUID_FFT_FORWARD, 0);
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int pos = 0;
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float in[2];
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while(fread(in, sizeof(float), 2, input) == 2) {
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fft_in[pos] = (in[1] + I * in[0]);
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pos += 1;
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if(pos == FFT_LEN) {
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pos = 0;
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fft_execute(fft);
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float fft_min = cabsf(fft_out[0]);
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float fft_max = cabsf(fft_out[0]);
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for(int i = 0; i < FFT_LEN; i++) {
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float mag = cabsf(fft_out[i]);
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if(mag < fft_min) {
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fft_min = mag;
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}
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if(mag > fft_max) {
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fft_max = mag;
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}
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}
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//printf("Min: %f Max: %f\n", fft_min, fft_max);
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for(int i = FFT_LEN / 2; i < FFT_LEN; i++) {
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float mag = cabsf(fft_out[i]);
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mag = (mag - fft_min) / (fft_max - fft_min);
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fprintf(output, "%f;", mag);
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}
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for(int i = 0; i < FFT_LEN / 2; i++) {
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float mag = cabsf(fft_out[i]);
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mag = (mag - fft_min) / (fft_max - fft_min);
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fprintf(output, "%f;", mag);
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}
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fprintf(output, "\n");
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}
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}
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fft_destroy_plan(fft);
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free(fft_in);
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free(fft_out);
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fclose(output);
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fclose(input);
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return 0;
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}
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