It is really just the pixel-resolution of the graph. The graph size is 252, but
the FFT size is 4096 ( giving 2049 points within the Nyquist frequency ).
So you will see magnitude peaks between the pixels as lower amplitude because
the screen doesn't display pixels between pixels.
I hope this makes sense,
Ed
Lone Shark "Aviation" out now on http://www.pyramidtransmissions.com
http://www.myspace.com/sharktracks
----- Original Message ----
From: Jason Plumb <[EMAIL PROTECTED]>
To: pd-list <pd-list@iem.at>
Sent: Sunday, 21 October, 2007 6:06:53 AM
Subject: [PD] Spectrum graphing amplitude problem
Hi.
I'm building a super simple but reconfigurable GOP spectrum graphing
abstraction, but got some weird behavior early on. Please see my
example:
http://noisybox.net/computers/pd/questions/freq_graph_work3.pd
The magnitude computation and dividing by the block size I got from one
of the help examples. It's almost doing the right thing -- if you drag
the slider around the single frequency peak moves around. The problem
is that the peak amplitude, as graphed, changes based on the frequency.
It even seems to be periodic WRT frequency, which makes me think
there's a kooky phase issue...
Any ideas?
Thanks,
-jason
http://noisybox.net
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