how to find cross correlation of two column vector

hi all, i have a problem to calculating cross correlation of two column vector which contains displacement of nodes at start and at end. i hv to calculate the time lag between them and plot that cross correlation against time..i did t=input(:,1); u1=input(:,2); u2=output(:,2); cc=xcorr(u1,u2); now how would i plot cc verses t, and how i find the time lag. plz help me

Answer 1

[Greg Heath]

The cross-correlation function is not a function of time. It is a function of time difference. In other words LAG. I don't have xcorr. However, the traditional approach has lag = -(Lmin-1):(Lmin-1) where Lmin = min(length(u1),length(u2));

I find the scaling

cc = xcorr(zscore(u1,1),zscore(u2,1))

to be convenient.

Hope this helps.

Thank you for formally accepting my answer.

Greg

[kavya saxena]

hi Gerg thanks for reply. actully i wnt to know tht how this lag can be determined.what will be the value of maxlag in terms of time. my both column vectors are of same length which start from zero to 3 microsecond with 0.05microsec time interval. i hv nodal displacement values at two different nodes in this time sequence. how would i can find the time difference between two nodes or i can say the time lag between them. help me to calculate this.