- #include "math.h"
- #define PI 3.1415926
- #define SAMPLENUMBER 512
- void InitForFFT();
- void MakeWave();
- void FFT();
- int INPUT[SAMPLENUMBER],DATA[SAMPLENUMBER];
- float fWaveR[SAMPLENUMBER],fWaveI[SAMPLENUMBER],w[SAMPLENUMBER];
- float sin_tab[SAMPLENUMBER],cos_tab[SAMPLENUMBER];
- main()
- {
- int i;
- InitForFFT();
- MakeWave();
- for ( i=0;i
- {
- fWaveR[i]=INPUT[i];
- fWaveI[i]=0.0f;
- w[i]=0.0f;
- }
- FFT(fWaveR,fWaveI);
- for ( i=0;i
- {
- DATA[i]=w[i];
- }
- while ( 1 ); // break point
- }
- void FFT(float dataR[SAMPLENUMBER],float dataI[SAMPLENUMBER])
- {
- int x0,x1,x2,x3,x4,x5,x6,x7,x8,xx;
- int i,j,k,b,p,L;
- float TR,TI,temp;
- for ( i=0;i
- {
- x0=x1=x2=x3=x4=x5=x6=x7=x8=0;
- x0=i&0x01; x1=(i/2)&0x01; x2=(i/4)&0x01; x3=(i/8)&0x01;x4=(i/16)&0x01; x5=(i/32)&0x01; x6=(i/64)&0x01;x7=(i/128)&0x01;x8=(i/256)&0x01;
- xx=x0*256+x1*128+x2*64+x3*32+x4*16+x5*8+x6*4+x7*2+x8;
- dataI[xx]=dataR[i];
- }
- for ( i=0;i
- {
- dataR[i]=dataI[i]; dataI[i]=0;
- }
- for ( L=1;L<=9;L++ )
- {
- b=1; i=L-1;
- while ( i>0 )
- {
- b=b*2; i--;
- }
- for ( j=0;j<=b-1;j++ )
- {
- p=1; i=9-L;
- while ( i>0 )
- {
- p=p*2; i--;
- }
- p=p*j;
- for ( k=j;k<512;k=k+2*b )
- {
- TR=dataR[k]; TI=dataI[k]; temp=dataR[k+b];
- dataR[k]=dataR[k]+dataR[k+b]*cos_tab[p]+dataI[k+b]*sin_tab[p];
- dataI[k]=dataI[k]-dataR[k+b]*sin_tab[p]+dataI[k+b]*cos_tab[p];
- dataR[k+b]=TR-dataR[k+b]*cos_tab[p]-dataI[k+b]*sin_tab[p];
- dataI[k+b]=TI+temp*sin_tab[p]-dataI[k+b]*cos_tab[p];
- }
- }
- }
- for ( i=0;i
- {
- w[i]=sqrt(dataR[i]*dataR[i]+dataI[i]*dataI[i]);
- }
- }
- void InitForFFT()
- {
- int i;
- for ( i=0;i
- {
- sin_tab[i]=sin(PI*2*i/SAMPLENUMBER);
- cos_tab[i]=cos(PI*2*i/SAMPLENUMBER);
- }
- }
- void MakeWave()
- {
- int i;
- for ( i=0;i
- {
- INPUT[i]=sin(PI*2*i/SAMPLENUMBER*30)*1024;
- }
- }
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