RE: a little puzzled with setting rx mux

GNU Radio
1

Hi Vincenzo,

There is a method to the madness!
http://gnuradio.org/doc/doxygen/classusrp__standard__rx.html#346488ad15ddefa75900e4d0a63574cc

Take a look at how each ddc is mapped.

  • George
2

really thanks George,

I figured it out and it seems to work…
now I’m wondering why, if I enable two channels from the usrp with :

    if not self.u.set_nchannels(nchan):
        sys.stderr.write('set_nchannels(%d) failed\n' % (nchan,))
        raise SystemExit

and attempt to transfer an 8 MHz bandwidth, the signals look and sound
good (once demodulated) but I keep getting “uOuOuOs…” which are not
there if the 2 channels are not enabled or the required bandidth is
below 8 MHz.
(processing demand to the host computer is however far below the maximum
allowed by my machine)

thanks for help
vincenzo

3

Hi Vincenzo,

I believe that this is because you are now attempting 16MHz total
bandwidth, 8 from each channel. If you have a decimation rate of 8, you
have 8Msps per second on one channel, and 8Msps on the other channel.
The USB bus cannot handle this… it’s not about your host computer.

  • George