Subtract data vectors with different frequencies

Hey!

I have the following problem: I have two vectors of pressure data, vector A taken at frequency 20000 Hz, vector B taken at frequency 1000 Hz.

Now I would like to get the difference in pressure B-A, but obviously I can't just subtract the two vectors given their different length.

Is there an elegant way to do this? Clearly it will involve averaging sections of vector A in order to bring down its size to that of vector B. I couldn't figure out a nice general way to do this, however.

Would be glad if someone could help! :)

-Alex

Answer 1

[Star Strider]

The best way is to use the Signal Processing Toolbox resample (link) function to resample the 20000 Hz sampling frequency vector to the size (and sampling frequency) of the 1000 Hz sampling frequency vector. The resample function is best for this (rather than interp1), since it uses an anti-alliasing filter. This is important if you want to do signal processing on both of them later.

[Alexander Waldenmaier]

Thank you very much!

[Star Strider]

My pleasure!

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