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Added window function to rffft

pull/10/head
Cees Bassa 2018-01-20 11:07:46 +01:00
parent 915ba68521
commit 7d0271b2b2
1 changed files with 15 additions and 8 deletions
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23
rffft.c
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@ -39,7 +39,7 @@ int main(int argc,char *argv[])
int16_t *ibuf;
char *cbuf;
float *fbuf;
float *z,length,fchan=100.0,tint=1.0,zavg,zstd;
float *z,length,fchan=100.0,tint=1.0,zavg,zstd,*zw;
char *cz;
double freq,samp_rate,mjd;
struct timeval start,end;
@ -143,6 +143,12 @@ int main(int argc,char *argv[])
fbuf=(float *) malloc(sizeof(float)*2*nchan);
z=(float *) malloc(sizeof(float)*nchan);
cz=(char *) malloc(sizeof(char)*nchan);
zw=(float *) malloc(sizeof(float)*nchan);
// Compute window
for (i=0;i<nchan;i++)
zw[i]=0.54-0.46*cos(2.0*M_PI*i/(nchan-1));
// Plan
fft=fftwf_plan_dft_1d(nchan,c,d,FFTW_FORWARD,FFTW_ESTIMATE);
@ -195,18 +201,18 @@ int main(int argc,char *argv[])
// Unpack
if (informat=='i') {
for (i=0;i<nchan;i++) {
c[i][0]=(float) ibuf[2*i]/32768.0;
c[i][1]=(float) ibuf[2*i+1]/32768.0;
c[i][0]=(float) ibuf[2*i]/32768.0*zw[i];
c[i][1]=(float) ibuf[2*i+1]/32768.0*zw[i];
}
} else if (informat=='c') {
for (i=0;i<nchan;i++) {
c[i][0]=(float) cbuf[2*i]/256.0;
c[i][1]=(float) cbuf[2*i+1]/256.0;
c[i][0]=(float) cbuf[2*i]/256.0*zw[i];
c[i][1]=(float) cbuf[2*i+1]/256.0*zw[i];
}
} else if (informat=='f') {
for (i=0;i<nchan;i++) {
c[i][0]=(float) fbuf[2*i];
c[i][1]=(float) fbuf[2*i+1];
c[i][0]=(float) fbuf[2*i]*zw[i];
c[i][1]=(float) fbuf[2*i+1]*zw[i];
}
}
@ -307,7 +313,8 @@ int main(int argc,char *argv[])
fftwf_free(d);
free(z);
free(cz);
free(zw);
return 0;
}