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

[Dawei Shen]

Hi, Eric

As far as know, Flex 400 only has a single subdevice. How do you use
one Flex400 daughter card for both transmission and reception at the
same time? Do you mean I use only one antenna using the TX/RX port, or
I use two antennas with one using Rx2 for reception and the other
using TX/RX port for transmisson?

Thanks

Dawei

On 4/14/06, Eric Blossom <address@hidden> wrote:
> 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
>