[PD] Spectrum graphing amplitude problem

Mathieu Bouchard matju at artengine.ca
Mon Oct 22 01:49:53 CEST 2007


On Sun, 21 Oct 2007, Jason Plumb wrote:

> I'm a bit new to FFT in the pd context, but I think I grok Nyquist -- 
> Sampling at S can, at best, yield the S/2 frequency (where S is the 
> sampling rate).  But how does this relate to block size in the DFT? Your 
> original statement sounds like the max frequency out of the fft is 
> (block size)/2...but that can't be right, eh?

The most rapid change you can have in a signal is an alternance of two 
values: e.g. +1, -1, +1, -1, +1, -1, ... which has S/2 frequency.

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| Mathieu Bouchard - tél:+1.514.383.3801, Montréal QC Canada


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