xcorr lag input to time?
8 visualizzazioni (ultimi 30 giorni)
I am trying to find the cross-correlation of two 1x180000 vectors (sigX and sigY). The sampling frequency is fs=1000. I am trying to find the xcorr with a lag of 30 s. How do I input the lag of -30:30 sec to the xcorr function given the sampling rate?
[c,lags] = xcorr(x,y,LAGS,'normalized');
The input 'm asking about is LAGS. Is this input in samples or time? If time, what unit of time?
David Goodmanson il 24 Mag 2023
Modificato: David Goodmanson il 24 Mag 2023
lags is a dimensionless index, so it's in samples (it has to be samples since xcorr has no way of knowing what fs might be). Since sampling frequency times a time interval is the number of samples, the input to xcorr is LAGS = (-30:30)*fs, a dimensionless index.
(This is assuming that 30* fs is exactly an integer, otherwise some rounding will be involved).