[amsat-bb] Re: SDX transponder timing delay measurements?

Howard Long howard at howardlong.com
Sun Sep 10 12:56:01 PDT 2006


Hello Douglas

> I know the design isn't even done yet, but has anyone 
> ever measured the time delay of an RF signal *through* 
> the (demo) version of SDX?

I think I can answer that. The buffering and the algorithm introduces a
32.5ms latency for a 100kHz passband.

The PC port is nasty because of Windows' buffering (I only use the Windows
Media API, not the lower latency options), so the latency on a PC platform
is more like 1/3 sec.

The embedded hardware takes 32.5ms from antenna to antenna, i.e. it is not
noticeable.

73 Howard G6LVB



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