Re: [Discuss-gnuradio] Multiple RX channels

[Eric Blossom]

On Thu, Aug 14, 2008 at 10:58:02PM -0400, Marcus Leech wrote:
> How do I arrange for there to be multiple input channels from the USRP
> when I have two Rx daughtercards?
> 
> I have a dual-polarization feed now, with dual DBS_RX cards, and I want
> to compute the cross product between
>   the two channels.
> 
> In my existing code, there's:
> 
>           self.u = usrp.source_c(decim_rate=options.decim)
>           self.u.set_mux(usrp.determine_rx_mux_value(self.u,
> options.rx_subdev_spec))
> 
> Can I do something like:
> 
>           self.u1 = usrp.source_c(decim_rate=options.decim)
>           self.u1.set_mux(usrp.determine_rx_mux_value(self.u1, 'a'))
> 
>           self.u2 = usrp.source_c(decim_rate=options.decim)
>           self.u2.set_mux(usrp.determine_rx_mux_value(self.u2, 'b'))
> 
> 
> Would that be what I wanted?
> 
> Cheers
> Marcus

Hi Marcus,

You only need one usrp.source_c.  The main difference is the setting
of the mux value to route the outputs of the A/Ds to the DDC. You'll
also need to set nchan=2 in the constructor, and deinterleave the
output of the source.  Take a look at
gnuradio-examples/python/usrp/usrp_wfm_rcv2_nogui.py (two streams from
the same daughterboard) and
gnuradio-examples/python/multi-antenna/multi_file.py (4 streams from 2
basic Rx d'boards).

Eric