Re: [Discuss-gnuradio] saturation with multi_fft.py

[Eric Blossom]

On Thu, Oct 11, 2007 at 02:11:38PM -0500, Tarun Tiwari wrote:
> Hi,
> Thanks everybody, this thread helped me a lot to understand the multi
> antenna cabability of gnuradio.
> I tried to run the multi_scope.py on a cingle USRP having two rfx2400
> daughterboards with following changes in current multi_scope.py:
> 
> 1) On line 44: nchan changed to 2 from 4
> 2) On Line 67: "len(self.subdev) != 4)"  changed to "len(self.subdev) != 2)"
> 3) On line 68 and 69: usrp_dbid.BASIC_RX changed to
> usrp_dbid.FLEX_2400_RX_MIMO_B
> 
> I generate sinusoid of 2.43G on a different machine/gnuradio and then run
> the command ./multi_scope.py -f2.43G -d128 -g0 on another machine with above
> changes, but i dont see anything other than noise on my scope. I tried
> different rbf files std_2rxhb_2tx.rbf, multi_2rxhb_2tx.rbf and got nothing,
> but the noise.
> 
> Next I changed the fpga_filename to multi_4rx_0tx.rbf, but i got following
> error:
> Can't find fpga bitstream: multi_4rx_0tx.rbf
> and program stoped with runtime error of "Can't open USRP"
> 
> Any suggestion?

If you're using only two channels, stick with the default rbf 
"std_2rxhb_2tx.rbf".

The RFX boards are quadrature.  The Rx mux setting should be:

  self.u.set_mux(gru.hexint(0x00003210))

Not

  self.u.set_mux(gru.hexint(0xf3f2f1f0))


Try turning the gain up.

Eric