<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman, new york, times, serif;font-size:12pt">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 ).<br>So you will see magnitude peaks between the pixels as lower amplitude because the screen doesn't display pixels between pixels.<br>I hope this makes sense,<br><br>Ed<br><div> </div><span>Lone Shark "Aviation" out now on <a target="_blank" href="http://www.pyramidtransmissions.com">http://www.pyramidtransmissions.com</a></span><br><span><a target="_blank" href="http://www.myspace.com/sharktracks">http://www.myspace.com/sharktracks</a></span><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><br><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">----- Original Message
----<br>From: Jason Plumb <jason@noisybox.net><br>To: pd-list <pd-list@iem.at><br>Sent: Sunday, 21 October, 2007 6:06:53 AM<br>Subject: [PD] Spectrum graphing amplitude problem<br><br>Hi.<br><br>I'm building a super simple but reconfigurable GOP spectrum graphing <br>abstraction, but got some weird behavior early on. Please see my
example:<br><br><a href="http://noisybox.net/computers/pd/questions/freq_graph_work3.pd" target="_blank">http://noisybox.net/computers/pd/questions/freq_graph_work3.pd</a><br><br>The magnitude computation and dividing by the block size I got from one
<br>of the help examples. It's almost doing the right thing -- if you drag
<br>the slider around the single frequency peak moves around. The problem <br>is that the peak amplitude, as graphed, changes based on the frequency.
<br> It even seems to be periodic WRT frequency, which makes me think <br>there's a kooky phase issue...<br><br>Any ideas?<br><br>Thanks,<br><br>-jason<br><a href="http://noisybox.net" target="_blank">http://noisybox.net</a><br><br>_______________________________________________<br><a ymailto="mailto:PD-list@iem.at" href="mailto:PD-list@iem.at">PD-list@iem.at</a> mailing list<br>UNSUBSCRIBE and account-management ->
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