lag time in matlab

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Susan
Susan on 2 Aug 2011
Answered: nadom mutlib on 16 Mar 2014
hey, I researched how to find the lag time in Matlab and I found a code that worked for the online example, but did not calculate the correct lag in mine.. I have two signal that are 2x100 size both and one is delayed version of other. The code though its complicated a bit, Is there a quicker way in Matlab to calculate the lag time, any in-built function?
mxlag=100; % Make a guess
R=zeros(2*mxlag+1,1);
for ilag=1:mxlag
t1=detrend(X(1:end-ilag),0); % Remove mean
t2=detrend(X1(ilag+1:end),0);
R(ilag+mxlag+1)=mean(t1.*t2)/(std(t1)*std(t2));
t1=detrend(X1(1:end-ilag),0);
t2=detrend(X(ilag+1:end),0);
R(mxlag+1-ilag)=mean(t1.*t2)/(std(t1)*std(t2));
end
% Zero lag
t1=detrend(X,0);
t2=detrend(X1,0);
R(mxlag+1)=mean(t1.*t2)/(std(t1)*std(t2));
lag=[-mxlag:mxlag]';
[Rmx,imx]=max(R);
num2str(lag(imx)*pi);
disp(['The calculated lag is: ' num2str(lag(imx)*pi)]);

Answers (1)

nadom mutlib
nadom mutlib on 16 Mar 2014
use cross correlation function it is easier. xcorr(x,y).

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