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ListCorrelate on lists with different sampling rates

  • To: mathgroup at smc.vnet.net
  • Subject: [mg87355] ListCorrelate on lists with different sampling rates
  • From: Curtis Osterhoudt <cfo at lanl.gov>
  • Date: Tue, 8 Apr 2008 05:39:12 -0400 (EDT)
  • Organization: LANL
  • Reply-to: cfo at lanl.gov

Hi, all, 

   I've been beating my head against this problem (only half an hour at a 
time, though, which may well be my mistake) for a little while now, and was 
wondering if people had some input.

   I'm basically looking at the cross-correlation (or sliding dot-product) of 
two sampled (discrete) signals---one a drive signal and one a received 
signal---to pick out various features. I'm doing this using Mathematica's 
ListCorrelate, which is working admirably, and I can easily pick out echoes 
and so on.

   However, my question concerns what to do when the sampled signals have 
different time scales. As I understand it, the ListCorrelate function really 
only works (for this application) when the input lists are one-dimensional. 
If the sampling rates are different, I can go ahead and (for example) 
resample the higher-sample-rate signal (via interpolation) to the same rate 
as the lower-sample-rate signal, and then perform the ListCorrelation. It 
seems to me, though, that I'm sort of throwing away some information that I 
don't need to in the resampling procedure.

   Is that the recommended procedure, or is there something more clever I can 
do?

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Curtis Osterhoudt
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