[Discuss-gnuradio] Re: TX/RX simultaneously using one USRP board

[Eric Blossom]

On Thu, Apr 13, 2006 at 01:47:00PM -0400, Dawei Shen wrote:
> Hi, Eric and other friends
> 
> Now I am working on a project that requires simutaneous TX/RX within
> one usrp board. I equip too FLEX400 daughter cards on one USRP board.

Why do you need two Flex 400's?

> What I am trying to do is to use the TX to retransmit (i.e. relay)
> what the USRP has received from the RX. Is it doable under the current
> framework of GNU Radio?

Yes it's possible.  No problem.  Only takes a single Flex 400, unless
you're trying to relay RX-A and RX-B at the same time.

  u_rx = usrp.source(0, ...)
  u_tx = usrp.sink(0, ...)

Then carry on as usual.

I'd start with a single Flex 400 that reads from the RX and then sends
to the TX.  You're probably going to need some kind of squelch or
power detection to determine whether or not to transmit.  In the
simple minded first cut, just send zeros when you don't want to transmit.


> If so, could you provide any hints on how to
> realize this? An obvious question to me is that in the Python code, we
> should either define the usrp as a source or a sink, but in my
> application, the USRP board serves as both sink and source. So what
> should I do in my case?
> 
> Thank you for your input
> 
> Dawei