PSN-L Email List Message

Subject: Re: WinQuake question for Larry
From: Brett Nordgren brett3nt@.............
Date: Sat, 28 Mar 2009 09:54:54 -0400


Many thanks.  I downloaded the (very) new WinQuake and now have the FFT 
data exported.  I think that it is exactly what I was looking for.

Now to get educated on spectral density stuff.


At 11:29 PM 3/27/2009 -0700, you wrote:
>Brett Nordgren wrote:
>>When I do an FFT on a PSN file, the result is normalized to fill the 
>>screen vertically.  Is there any way to extract the normalization factor 
>>so that I could use the results to generate a calibrated noise spectrum?
>Not within WinQuake. With the current version of WQ you can export the raw 
>FFT data so you can analyze the FFT data using other programs like MATLAB 
>or Excel. To do this create an FFT Window and use the File / Export menu 
>items. The resulting file will look like this:
>The first number is the frequency then the real and imaginary numbers from 
>the FFT function and then the magnitude. The magnitude is calculated using 
>the following C code
>mag = hypot(Real[i] , Imag[i] );
>Larry Cochrane


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