关于fft

Question

使用fft算法确定采集点中频谱的变化中，是否振幅一样的波，分析出来的高度(值)是一样???现在假设1024个模拟的点；连个频率同时输进:double ff1= 2.0*PI*(f1)/F;//F--为采样频率;f1;f2为模拟的频率;
double ff2=2.0*PI*(f2)/F;
double ri[1024];  //fft数据源--模拟的采集点;
for (int i=0;i<1024;i++)
{
double k=sin(ff1*i);
k+=sin(ff2*i);
ri[i]=k;
}这样对数据源进行fft;是否这两个频率确定的频谱高度是一样的???我现在的结果不是一样高，但是变换不是很大;其中fft的代码如下://-----------------------------------------------------------------------------
  void fft1(double *br,double  *bi,
                    int il,const double *st,const double *ct)
  {
          //the size of br,bi should be equal to il.
          //and size of st and ct no less than il.
          int is=il>>1;
          int mpx=0;
          int ic=1;
          int ia;          while(is)
          {
                  is>>=1;
                  mpx++;
          }          is=il;          for(ia=1;ia<=mpx;ia++)
          {
                  int ib;
                  int ka=0;
                  is>>=1;
                  for(ib=1;ib<=ic;ib++)
                  {
                          int in=1;
                          int k;
                          for(k=1;k<=is;k++)
                          {
                                  int j1=ka+k;
                                  int j2=j1+is;
                                  double xr=br[j1];
                                  double xi=bi[j1];
                                  double yr=br[j2];
                                  double yi=bi[j2];
                                  br[j1]=xr+yr;
                                  bi[j1]=xi+yi;
                                  xr-=yr;
                                  xi-=yi;
                                  br[j2]=xr*ct[in]-xi*st[in];
                                  bi[j2]=xr*st[in]+xi*ct[in];
                                  in+=ic;
                          }
                          ka+=is<<1;
                  }
                  ic<<=1;
          }
  }  void binrv(double *bc,int il,const int *lb)
  {
          int is=il-1;
          int i;
          for(i=2;i<=is;i++)
          {
                  int ig=lb[i];
                  if(ig<=i)
                          continue;
                  double xx=bc[i];
                  bc[i]=bc[ig];
                  bc[ig]=xx;
          }
  }  void brtab(int *lbr,int il)
  {
          int is=il>>1;
          int mpx=0;
          while(is)
          {
                  is>>=1;
                  mpx++;
          }
          int ln;
          for(ln=1;ln<=il;ln++)
          {
                  int j1=ln-1;
                  int ibord=0;
                  for(int k=1;k<=mpx;k++)
                  {
                          int j2=j1>>1;
                          ibord=ibord*2+(j1-2*j2);
                          j1=j2;
                  }
                  lbr[ln]=ibord+1;
          }
  }  void cstab(double *st,double *ct,int il,int ity)
  {
          double yy;
          yy=-PI*2.0/il;
          if(ity<0)
                  yy=-yy;
          int l;
          double ang=0.0;
          for(l=1;l<=il;l++)
          {
                  st[l]=sin(ang);
                  ct[l]=cos(ang);
                  ang+=yy;
          }
  }  void __fastcall FFT(double *br,double *bi,int n,int ity) 
  //ity>0 forward ,ity<0 backward
  //n=pow(2,m);
  //Here br and bi start from 0.
  {
          double *ct,*st;
          int *il;
          if(n<=0)
                  return;
          double invsqrtn=1.0/sqrt(n);
          ct=(double *)malloc(sizeof(double)*n)-1;
          st=(double *)malloc(sizeof(double)*n)-1;
          cstab(st,ct,n,ity);
          il=(int *)malloc(sizeof(int)*n)-1;
          brtab(il,n);
          fft1(br-1,bi-1,n,st,ct);
          binrv(br-1,n,il);
          binrv(bi-1,n,il);
          for(int i=0;i<n;i++)
          {
                  br[i]*=invsqrtn;
                  bi[i]*=invsqrtn;
          }
          free(il+1);
          free(ct+1);
          free(st+1);
  }
是否我的算法有问题？？？