can someone please explain what is lag in matlab built in function xcov ? Thanks

please see above, thanks

Answer 1

[Prajit T R]

[c,lags] = xcov(x,y,maxlags) where x and y are length m vectors, returns the cross-covariance sequence in a length 2*maxlags+1 vector c. lags is a vector of the lag indices where c was estimated, that is, [-maxlags:maxlags]. These indices can be useful when you wish to plot the covariance estimates. For example: stem(lags,c)