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From: | Marcus D. Leech |
Subject: | Re: [Discuss-gnuradio] WX GUI FFT Sink Performance |
Date: | Thu, 16 May 2013 09:49:59 -0400 |
User-agent: | Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.24) Gecko/20111108 Fedora/3.1.16-1.fc14 Thunderbird/3.1.16 |
Because apparently SpectrumLab is using an overlapped FFT implementation. The one in wXGUI doesn't. Further, the wxGUI implmentation has far too much Python involved in processing samples, so trying to process 65536 samples at a time is likely sluggish, to the point that it can't keep up in real time. The underlying FFT implementation itself is very fast--Gnu Radio uses FFTW. I've regularly built FFT filters with 250e3 taps, and they are able to run in real time with sample rates into the many Msps. So, if you do the math, a non-overlapped FFT implementation of 65536 bins at 192Ksps means 2.92 FFTs/second. If the display update rate is more than that, there's no way to actually produce an update rate faster than 2 per second under those circumstances, with a non-overlapped FFT. -- Marcus Leech Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org |
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