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[linrad] Processing delay



Hi All,

I have started to collect some examples of different ways to run Linrad
at this URL: http://www.sm5bsz.com/linuxdsp/usage/examples.htm

The first example is with a fast waterfall on which CW is readable and
filter choices for a very fast response. The delay from antenna to
loudspeaker can be as low as 10 milliseconds for use with QSK.

The fast waterfall makes this way of using Linrad too demanding for
Windows 2000 at 96 kHz bandwidth on a 2.667 GHz Pentium 4. It is
possible, but not quite OK under X11 but with svgalib there is a good
margin.

The timings are with Linrad-02.04. Earlier versions had fixed block
sizes for A/D and D/A to give a hardware interrupt rate of about 50 Hz
(20+20 ms delay) Now Linrad takes a decision based on the filter
delay and sets small blocksizes when the user seems to want fast
response. The small blocksize will of course cause some extra CPU load
but this will not affect operation with normal filter bandwidths.

73

Leif / SM5BSZ



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