Cross Correlation analysis with two series of wavelets

[MrSak87]

Hey all,

This one will be a tough one to explain...

I essentially have 3 columns of data and 40000+ rows of it. Column A measures seconds from time 0 to say 10. Column B is a series of values creating on a graph wavelets from a source detected by receiver one and Column C is the same series of wavelets detected by receiver two. The two receivers are relatively closely spaced apart and therefore the profiles of these waves will be very similar although NOT identical. The spacing between the wavelets also changes due to the density of the soil/rock they travel throughThe aim is for excel to detect the peaks of each correlating wave and detect the lag time between the two series at each source. An example of a lag between two wavelets is shown

https://www.google.co.uk/search?q=w...o.com%2Fcalculator-timedelayphase.htm;365;152

This lag time calculation (column 4!?) allows me to do all the statistical analysis for my job. The traditional way is to manually pick the peaks using ancient software but this simply isn't feasible with the amount of data I have.

My VB ability is marginally better than just recording but only slightly.

Please help!
Sean

 

[shg]

Works perfectly! Thank you, you've no idea how much time I've spent trying to figure this out.

You're welcome.

What do you mean by time dilation? Do you mean the amount of time change between the two waves as if one was stretched? If so how would I go about this?

Assuming that the signals start out with zero offset, and then one becomes progressively delayed (like Doppler shift from a receding object), you would need to resample the slower one (W2'(t) = W2(kt), k > 1) by different amounts and see where the correlation peaks. If there is no underlying phenomonology to suggest that this should happen, it would probably be a waste of time. Either way, I'll leave it to you.

 

[MrSak87]

Ahhh I get you, We start out with a zero offset from the source of the wave, but there are two receivers detecting that wave which are slightly offset. It's this difference that we use to calculate the velocity of the wave.

Thanks again for your help you've saved me a lot of bother