Forum: GNU Radio Limiting TX output

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Brian Johnson (Guest)
on 2006-05-03 21:08
(Received via mailing list)
Can anyone tell me if there is something I can do in the existing GNU
software which will limit the output of a TX daughter board to a preset
maximum?  We are using the LFTX daughter boards.

We are running the TX output to an amp that will boost the signal up to
watts, and are already using the gain settings to adjust the TX output.
problem is that voice transmission has a lot of spikes on things like
and 'c' sounds or blowing into the microphone.  To prevent blowing the
we have had to adjust our TX gain such that the spikes stay below ~170mV
(peak-to-peak).  With this we are only getting about 2-3 watts PEP on
speech.  We would like to allow more gain - getting us closer to 8 watts
and just "clip" the spikes to protect the amp.

I know this can be done in hardware between the USRP and amp, but would
rather do it in software if possible.

Brian Johnson

Kutta Consulting Inc.

Work: 602-896-1976

Cell   : 623-451-9417
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