# xcorr lag input to time?

8 visualizzazioni (ultimi 30 giorni)
Carly il 23 Mag 2023
Modificato: Carly il 24 Mag 2023
Hello,
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?
Thank you
##### 0 CommentiMostra -1 commenti meno recentiNascondi -1 commenti meno recenti

Accedi per commentare.

### Risposta accettata

David Goodmanson il 24 Mag 2023
Modificato: David Goodmanson il 24 Mag 2023
Hi Carly,
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).
##### 1 CommentoMostra NessunoNascondi Nessuno
Carly il 24 Mag 2023
thank you!

Accedi per commentare.

### Categorie

Scopri di più su Correlation and Convolution in Help Center e File Exchange

R2022b

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!