www.pudn.com > WavePlayer_Final.rar > FFT.h

// FFT.h: interface for the CFFT class. 
//这个类是我从网上DOWN了一些FFT的程序例子然后封成一个类的 
////////////////////////////////////////////////////////////////////// 
 
#if !defined(AFX_FFT_H__5884C7E3_571D_4913_B222_DC3AE8648DEC__INCLUDED_) 
#define AFX_FFT_H__5884C7E3_571D_4913_B222_DC3AE8648DEC__INCLUDED_ 
 
#include "math.h" 
 
#if _MSC_VER > 1000 
#pragma once 
#endif // _MSC_VER > 1000 
template  
class CFFT   
{ 
private: 
	T* m_pSource,m_pDest; 
	UINT m_nLength; 
public: 
	CFFT(T* pSource,UINT nLength); 
	virtual ~CFFT(); 
	 
	short Do(); 
	void FFT(double *pr,double *pi,int n,int k,double *fr,double *fi,int l,int il); 
 
}; 
 
 
template  
CFFT::CFFT(T* pSource,UINT nLength) 
{ 
	m_pSource=pSource; 
//	m_pDest=pDest; 
	m_nLength=nLength; 
} 
template  
CFFT::~CFFT() 
{ 
	 
} 
template  
short CFFT::Do() 
{ 
	UINT n,k=1,i; 
	short nMax; 
	while (1) 
	{ 
		n=pow(2,k); 
		if (n 
void CFFT::FFT(double *pr,double *pi,int n,int k,double *fr,double *fi,int l,int il) 
{ 
	int it,m,is,i,j,nv,l0; 
    double p,q,s,vr,vi,poddr,poddi; 
    for (it=0; it<=n-1; it++) 
      { m=it; is=0; 
        for (i=0; i<=k-1; i++) 
          { j=m/2; is=2*is+(m-2*j); m=j;} 
        fr[it]=pr[is]; fi[it]=pi[is]; 
      } 
    pr[0]=1.0; pi[0]=0.0; 
    p=6.283185306/(1.0*n); 
    pr[1]=cos(p); pi[1]=-sin(p); 
    if (l!=0) pi[1]=-pi[1]; 
    for (i=2; i<=n-1; i++) 
      { p=pr[i-1]*pr[1]; q=pi[i-1]*pi[1]; 
        s=(pr[i-1]+pi[i-1])*(pr[1]+pi[1]); 
        pr[i]=p-q; pi[i]=s-p-q; 
      } 
    for (it=0; it<=n-2; it=it+2) 
      { vr=fr[it]; vi=fi[it]; 
        fr[it]=vr+fr[it+1]; fi[it]=vi+fi[it+1]; 
        fr[it+1]=vr-fr[it+1]; fi[it+1]=vi-fi[it+1]; 
      } 
    m=n/2; nv=2; 
    for (l0=k-2; l0>=0; l0--) 
      { m=m/2; nv=2*nv; 
        for (it=0; it<=(m-1)*nv; it=it+nv) 
          for (j=0; j<=(nv/2)-1; j++) 
            { p=pr[m*j]*fr[it+j+nv/2]; 
              q=pi[m*j]*fi[it+j+nv/2]; 
              s=pr[m*j]+pi[m*j]; 
              s=s*(fr[it+j+nv/2]+fi[it+j+nv/2]); 
              poddr=p-q; poddi=s-p-q; 
              fr[it+j+nv/2]=fr[it+j]-poddr; 
              fi[it+j+nv/2]=fi[it+j]-poddi; 
              fr[it+j]=fr[it+j]+poddr; 
              fi[it+j]=fi[it+j]+poddi; 
            } 
      } 
    if (l!=0) 
      for (i=0; i<=n-1; i++) 
        { fr[i]=fr[i]/(1.0*n); 
          fi[i]=fi[i]/(1.0*n); 
        } 
    if (il!=0) 
      for (i=0; i<=n-1; i++) 
        { pr[i]=sqrt(fr[i]*fr[i]+fi[i]*fi[i]); 
          if (fabs(fr[i])<0.000001*fabs(fi[i])) 
            { if ((fi[i]*fr[i])>0) pi[i]=90.0; 
              else pi[i]=-90.0; 
            } 
          else 
            pi[i]=atan(fi[i]/fr[i])*360.0/6.283185306; 
        } 
    return; 
} 
 
#endif // !defined(AFX_FFT_H__5884C7E3_571D_4913_B222_DC3AE8648DEC__INCLUDED_)