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Re: power spectrum

  • To: mathgroup at
  • Subject: [mg52742] Re: [mg52695] power spectrum
  • From: Sseziwa Mukasa <mukasa at>
  • Date: Sat, 11 Dec 2004 05:22:05 -0500 (EST)
  • References: <>
  • Sender: owner-wri-mathgroup at

On Dec 9, 2004, at 8:23 PM, George Szpiro wrote:

> If I have a string of data - let us say a time series of 200  
> observations -
> how can I find the power spectrum? I did Fourier[list] but have no  
> idea what
> the output means.
> Thank you for any help (please to my email address:
> george at

If your data is real valued


will give you the power spectrum from frequencies 0 to half your sample  

For complex valued observations


will give you the power spectrum from -1/2*sample rate to 1/2*sample  
rate - 1/(Length[list] * sample rate).

As for what it all means, section 13.4 of Numerical Recipes  
( explains power spectra.



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