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#include <fftw3.h>
#include <stdlib.h>
#define N 1024
#define DEMI_PER 16
#define AMPLITUDE 5
void show_signal(double * in, unsigned long size)
{
unsigned long i;
for( i = 0 ; i < size ; i++ )
{
fprintf(stdout," %f \n",in[i] );
}
}
void show_fftw_complex(fftw_complex * in, unsigned long size)
{
unsigned long i;
for( i = 0 ; i < size ; i++ )
{
fprintf(stdout,"%f \n",in[i][0]);
}
}
int main ( int argc, char **argv)
{
double *in;
unsigned long i,j = 0;
fftw_complex * out;
fftw_plan p;
in = malloc( N * sizeof(double));
out = fftw_malloc( N * sizeof(fftw_complex));
/* Initialisation du plan de calcul pour la fft */
p = fftw_plan_dft_r2c_1d(N,in,out,FFTW_ESTIMATE);
/* Création d'un signal pseudo rectangle */
for( i = 0 ; i < N ; i++)
{
if( i % DEMI_PER == 0 )
{
if ( j == AMPLITUDE )
j = 0;
else
j = AMPLITUDE;
}
in[i] = j;
}
/* Affiche le signal d'entrée */
show_signal(in,N);
/* Calcule la fft */
fftw_execute(p);
/* Affiche la TF du signal d'entrée */
show_fftw_complex(out,N/2);
fftw_destroy_plan(p);
free(in);
fftw_free(out);
return EXIT_SUCCESS;
} |
