Multiple RX channels

GNU Radio
1

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

2

On Thu, Aug 14, 2008 at 10:58:02PM -0400, Marcus L. wrote:

      self.u.set_mux(usrp.determine_rx_mux_value(self.u,

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