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RE: [linrad] FFT performance
- Subject: RE: [linrad] FFT performance
- Date: Fri, 15 Nov 2002 11:43:39 +0100
> I can't get to the screen where the values are displayed. This is what is
> happening with details:
> $ ./linrad
> ADC sampling is set to 8000, 2 channels (I/Q receiver). Parameters are
> saved (W pressed).
> At the main screen I press "F" for the hardware test mode. The message
> "You are prompted to the parameter selection screens for the following
> reason: par_test file missing". Then at the "Set parameters for mode:
> HARDWARE TEST MODE RX CHannels: 1" screen, no matter what values I set,
> when I press enter, linrad always tells that "Speed far too slow. Try less
> demanding FFT!". That is it. The only way to get out is to press ESC, thus
> quiting the application.
Most probably something is wrong with your device driver. It was already
tested in the setup process and I do not know why it does not work here.
There are many problems with different device drivers not really
following the specifications. Some may give incorrect info about the
buffer pointers for example.
Did you get any choice at all in the A/D setup? Try a different device
if there is one, otherwise try RDWR or RDONLY and possibly another input
Problems like this are common with ALSA but OSS usually works well.
With a sampling speed of 8000 and fft1 bandwidth 100Hz or above you
should not see the "Speed far too slow" message even on a 486 computer
so the speed is surely evaluated incorrectly.
Check the soundcard_init.log file. Perhaps it contains some
You may download a really old Linrad version and check if the problem
is present. I have done some changes in order to work around some of
Leif / SM5BSZ