xcorr can't be used

Hi, I met a problem as below, who knows which tool box I need to install? The version of matlab I used is R2015b

Thanks

Answer 1

[Adam Danz]

xcorr does not require Signal Processing Toobox in Matlab R2019a and later.

For Matlab releases prior to 19a,, you'll need the Signal Processing Toobox as the error message indicates. Alternatively, you could compute the cross correlation with your own function or search for an alternative on the File Exchange.

[Min Wang]

I have find some code about xcorr and save it as .m file. then this issue fixed. Thank you all the same.