PSN-L Email List Message
Subject: Re: Re: FFT Waterfall display
From: "Michael Kimzey" mckimzey@...........
Date: Sat, 14 Jul 2007 08:09:29 -0400
>The power needed for a realtime FFT display
>of any value just does not exist for a typical
>home computer. You would need a special
>card like these high speed video cards.
>I have seen the machines that do real time fft
>and back in the 1970s they were like 1000X faster
>than your home computer and would do 500 points
>and be only a few milli seconds behind real time.
I'm don't completely understand all this FFT stuff, but a search of google
revealed that you can get several programs for FFT and waterfall display.
http://www.relisoft.com/science/Physics/fft.html <- provides a discussion
of FFT and source code.
Digipan - this is a amature radio program for communicating digitally using
audio output from your sound card and has a very nice waterfall display.
Maybe these are not doing something "FFT-wise", but Spectrograph and
Spectran both allow you to set the FFT size and both have the moving
graphical display...and are working on signals with sample rates of 44,000
per second. I think that any seismological waterfall display would move
-very- slowly...my samples-per-second are only 10 and should be able to
perform some type of FFT. Even Win-Quake does FFT. Maybe I'm missing
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