function xc=xcorr_fft(x1,x2)
%uses an fft to compute a periodic cross correlation b/w x1 and x2
X1=fft(x1);
X2=fft(x2);
xc=ifft(X1.*conj(X2));
%
%Copyright (c) 2009, Travis Wiens
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%modification, are permitted provided that the following conditions are
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% notice, this list of conditions and the following disclaimer.
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%THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
%AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
%IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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%INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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% contact Travis at travis.mlfx@nutaksas.com
