Honored Contributor
Honored ContributorHi Saket,
The title of your post indicates that you want an autocorrelation. However, the FIR filtering option Kaz suggested (nice suggestion!) is effectively a cross-correlation; the filter coefficients are a sinusoid with the same frequency as the transmitted signal. If you 'filter' an incoming signal with this filter, then you will get peaks where the two signals are in phase, and zeroes where they are out of phase (if the filter length is only one period, then you only get one peak). Basically, you get the autocorrelation you are looking for with a different scaling, and a shift of the zeroth lag. You need to figure out what it is you really want first; auto- or cross-correlation. What parameter are you trying to determine? If you are simply looking for a power detection or system gain response, then an autocorrelation is sufficient. If you want timing information (delay or phase), then you need a cross-correlation. You then need to determine how unambiguous you need that time estimate, eg., a sinusoid is ambiguous every period (you can shift the received signal by a full period, and you will get the same cross-correlation result). Cheers, Dave
