Thread Subject: Effect of periodic nonuniform sampling of data to FFT

Subject: Effect of periodic nonuniform sampling of data to FFT

From: juho salminen

Date: 5 Nov, 2009 09:47:01

Message: 1 of 1

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Hi,

I have sine wave, which I'm sampling with time moments, which have some periodic gaps. I'm sampling, for example, time moments 1:10 , then 12:22, then 24:34 etc..
So, when sampled sine wave is plotted in time domain, one can see that sine wave has discontinuity points between samples 10 and 11, 21 and 31 etc.

When I'm plotting this in freqeuncy domain with fft function, I can see some unexpected behaviour: Intead of one spike, several another spikes occurs very periodically around main spike (frequenvy of sine).

What would cause this, and how to avoid such a behaviour? Why those spikes are so periodical ?

Thanks already for answers!
  

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nonuniform John 9 Nov, 2009 10:37:04
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