tailscrap.m
上传用户:ozl2332
上传日期:2009-12-28
资源大小:38k
文件大小:1k
- function maxabsdiff=tailscrap()
- % test code for circular convolution with the scrapped portion
- % at the tail of the buffer, rather than the front
- %
- % The idea is to rotate the zero-padded h (impulse response) buffer
- % to the left nh-1 samples, rotating the junk samples as well.
- % This could be very handy in avoiding buffer copies during fast filtering.
- nh=10;
- nfft=256;
- h=rand(1,nh);
- x=rand(1,nfft);
- hpad=[ h(nh) zeros(1,nfft-nh) h(1:nh-1) ];
- % baseline comparison
- y1 = filter(h,1,x);
- y1_notrans = y1(nh:nfft);
- % fast convolution
- y2 = ifft( fft(hpad) .* fft(x) );
- y2_notrans=y2(1:nfft-nh+1);
- maxabsdiff = max(abs(y2_notrans - y1_notrans))
- end