26 lines
653 B
Matlab
26 lines
653 B
Matlab
function maxabsdiff=tailscrap()
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% test code for circular convolution with the scrapped portion
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% at the tail of the buffer, rather than the front
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%
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% The idea is to rotate the zero-padded h (impulse response) buffer
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% to the left nh-1 samples, rotating the junk samples as well.
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% This could be very handy in avoiding buffer copies during fast filtering.
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nh=10;
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nfft=256;
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h=rand(1,nh);
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x=rand(1,nfft);
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hpad=[ h(nh) zeros(1,nfft-nh) h(1:nh-1) ];
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% baseline comparison
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y1 = filter(h,1,x);
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y1_notrans = y1(nh:nfft);
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% fast convolution
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y2 = ifft( fft(hpad) .* fft(x) );
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y2_notrans=y2(1:nfft-nh+1);
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maxabsdiff = max(abs(y2_notrans - y1_notrans))
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end
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