我实现了来自 ''Proceedings of the IEEE'', N. Jeremy Kasdin (page 825) pdf的以下代码。但我不明白这些行,因为我没有数字食谱书:
/* perform the discrete Fourier transform */
realft (hfa,n_pts, 1);
realft (wfa,n_pts, 1);
wfa[1]=wfa[1]*hfa[1];
wfa[2]=wfa[2]*hfa[2];
for(i=3;i<=nn;i+=2) {
wr=wfa[i];
wi=wfa[i+1];
wfa[il=wr*hfa[i]-wi*hfa[i+1];
wfa[i+l]=wr*hfa[i+1]+wi*hfa[i];
}
有人可以给我一些指示吗?