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Cross-correlation

`r = xcorr(x,y)`

`r = xcorr(x)`

`r = xcorr(___,maxlag)`

`r = xcorr(___,scaleopt)`

```
[r,lags]
= xcorr(___)
```

returns
the cross-correlation of two discrete-time sequences, `r`

= xcorr(`x`

,`y`

)`x`

and `y`

.
Cross-correlation measures the similarity between `x`

and
shifted (lagged) copies of `y`

as a function of
the lag. If `x`

and `y`

have
different lengths, the function appends zeros at the end of the shorter
vector so it has the same length, *N*, as the other.

`r = xcorr(___,`

limits
the lag range from –`maxlag`

)`maxlag`

to `maxlag`

.
This syntax accepts one or two input sequences. `maxlag`

defaults
to *N* – 1.

[1] Buck, John R., Michael M. Daniel, and Andrew C. Singer. *Computer
Explorations in Signals and Systems Using MATLAB ^{®}*.
2nd Edition. Upper Saddle River, NJ: Prentice Hall, 2002.

[2] Stoica, Petre, and Randolph Moses. *Spectral
Analysis of Signals*. Upper Saddle River, NJ: Prentice
Hall, 2005.