[USRP-users] X310, 2 Basic RX and quad DDC

Gwenhael Goavec-Merou gwenj at trabucayre.com
Wed Jul 12 05:21:18 EDT 2017


Hello Derek and Martin.

Thank you for your answers.

I need to have DDC and to propagate to the computer 4 complex flow.

I've read design code for X310 and I wish to know if it's possible for
someone, without a big knowledge about this design (and globally USRP's
design), to add this option (and to contribute). If it's possible I'm
open for all advices about how to do this.

Thank you very much
Gwen

On Wed, 5 Jul 2017 21:20:16 +0100
Derek Kozel via USRP-users <usrp-users at lists.ettus.com> wrote:

> Hello Gwen,
> 
> There is no currently supported way of obtaining four real valued
> sample streams from a pair of BasicRX daughterboards. However, if you
> do not use any DDC (CORDIC) frequency shift then there will be no
> energy transfer between the I and Q values in the complex stream. You
> can then unpack the complex samples into a pair of real valued
> samples on the host side application.
> 
> Regards,
> Derek
> 
> On Wed, Jul 5, 2017 at 8:51 PM, Martin Braun via USRP-users <
> usrp-users at lists.ettus.com> wrote:
> 
> > On 06/29/2017 01:09 AM, gwenhael.goavec via USRP-users wrote:  
> > > Hi,
> > >
> > > I use an x310 with 2 basic RX daughterboard.
> > >
> > > Currently I inject one "real" signal in channelA for side A and a
> > > second "real" signal in channelA for side B. Now I wish to inject
> > > 4 "real" signals in my USRP and receiving 4 demodulated/filtered
> > > IQ dataflow on my computer. It's theorically possible because
> > > BasicRx daughterboard do nothing.
> > >
> > > I've read the Vivado design for this USRP and I've seen in
> > > x300_core.v (in fact rfnoc_ce_default_inst_x310.v) 2 x
> > > noc_block_ddc : I suppose (I'm wrong ?) each of them receive 2
> > > dataflow of one ADC (chanA and chanB).
> > >
> > > In this module 2 DDC are instanciated. Consequently It's seems to
> > > have 4 demodulation using cordic24 and 4 CIC.
> > >
> > > Consequently, I suppose my need is possible with official X310
> > > firmware but I'm don't know how to configure, through uhd or
> > > gnuradio, my USRP to provide I0Q0I1Q1I2Q2I3Q3 (this order is not
> > > mandatory).
> > >
> > > My assumption is true (or not)? If it's possible someone here
> > > could help me for this configuration?  
> >
> > Gwen,
> >
> > this is not (currently) a supported configuration on the X300.
> >
> > Regards,
> > Martin
> >
> > _______________________________________________
> > USRP-users mailing list
> > USRP-users at lists.ettus.com
> > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
> >  




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