RE: [Discuss-gnuradio] Mux settings...

[Jared Jensen]

Thanks.  That means I have issues.  :)  I am trying to use 2 channels, with a mux setting of 0x32103210.  I have a DBSRX on RXA and another one on RXB.  I have no TX.  When I do a...

nRead = myDev->read(arr, USB_BUF_SIZE, &bOverrun);

I get perfect data from one channel.  (i.e. I_a = arr[0], Q_a = arr[1], I_a = arr[4], Q_a = arr[5] and so on.)  But I get complete junk on the second channel.  (I_a = arr[2], Q_a = arr[3], I_a = arr[6], Q_a = arr[7]).

I've swapped the boards (slot A to slot B and vice versa), and they both seem to work fine.  I've run usrp_fft.py -R B and -R A and it works in both cases, but I can't find anything to test both at once.  But regardless, I don't think it's the USRP's fault.  It think it's mine unfortunately.  I'm just out of ideas where to look.  I've been debugging this for a couple of days now.  Ugh.  :)  Any thoughts?

Jared

> Date: Mon, 22 Oct 2007 17:15:08 -0700
> From: address@hidden
> To: address@hidden
> CC: address@hidden
> Subject: Re: [Discuss-gnuradio] Mux settings...
>
> On Mon, Oct 22, 2007 at 05:13:33PM -0400, Jared Jensen wrote:
> >
>
> > What are the proper mux settings for one DBSRX in RXA and one DBSRX
> > in RXB? When I used a single DBSRX in RXA 0x00000010 worked well.
> > But now I want Channel 0 to be RXA, and Channel 1 to be RXB both of
> > which are I and Q, and not swapped.
> >
> > So far anything other than 0x32103210 or 0x00000010 produces dirty
> > output with random-looking noise in the data.
> >
> > Jared
>
> If you're using a single channel, usrp.determine_rx_mux_value will get you
> the right answer, regardless of the type of daughterboard.
>
> On the DBSRX, 0x00003210 (or for that matter 0x32103210) will set you
> up with side A routed to channel 0 and side B routed to channel 1.
>
> See http://gnuradio.org/trac/wiki/UsrpRfxDiagrams
> and http://gnuradio.org/doc/doxygen/classusrp__standard__rx.html
>
> Eric
>

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