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//
// symstreamcf_example.c
//
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "liquid.h"
#define OUTPUT_FILENAME "symstreamcf_example.m"
int main()
{
// symstream parameters
int ftype = LIQUID_FIRFILT_ARKAISER;
unsigned int k = 4;
unsigned int m = 9;
float beta = 0.30f;
int ms = LIQUID_MODEM_QPSK;
// spectral periodogram options
unsigned int nfft = 2400; // spectral periodogram FFT size
unsigned int num_samples = 80000; // number of samples
unsigned int i;
// create spectral periodogram
spgramcf periodogram = spgramcf_create_default(nfft);
unsigned int buf_len = 1024;
float complex buf[buf_len];
// create stream generator
symstreamcf gen = symstreamcf_create_linear(ftype,k,m,beta,ms);
symstreamcf_print(gen);
unsigned int total_samples = 0;
while (total_samples < num_samples) {
// write samples to buffer
symstreamcf_write_samples(gen, buf, buf_len);
// push resulting sample through periodogram
spgramcf_write(periodogram, buf, buf_len);
// accumulated samples
total_samples += buf_len;
}
printf("total samples: %u\n", total_samples);
// compute power spectral density output
float psd[nfft];
spgramcf_get_psd(periodogram, psd);
// destroy objects
symstreamcf_destroy(gen);
spgramcf_destroy(periodogram);
//
// export output file
//
FILE * fid = fopen(OUTPUT_FILENAME,"w");
fprintf(fid,"%% %s : auto-generated file\n", OUTPUT_FILENAME);
fprintf(fid,"clear all;\n");
fprintf(fid,"close all;\n\n");
fprintf(fid,"nfft = %u;\n", nfft);
fprintf(fid,"f = [0:(nfft-1)]/nfft - 0.5;\n");
fprintf(fid,"H = zeros(1,nfft);\n");
for (i=0; i<nfft; i++)
fprintf(fid,"H(%6u) = %12.4e;\n", i+1, psd[i]);
fprintf(fid,"figure;\n");
fprintf(fid,"plot(f, H, '-', 'LineWidth',1.5);\n");
fprintf(fid,"xlabel('Normalized Frequency [f/F_s]');\n");
fprintf(fid,"ylabel('Power Spectral Density [dB]');\n");
fprintf(fid,"grid on;\n");
fprintf(fid,"axis([-0.5 0.5 -120 20]);\n");
fclose(fid);
printf("results written to %s.\n", OUTPUT_FILENAME);
printf("done.\n");
return 0;
}
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