Re: [Discuss-gnuradio] Re: Re: Tx Path

[Eric Blossom]

On Wed, Apr 18, 2007 at 01:49:36PM +0200, Anmar wrote:
> Eric Blossom wrote:
> 
> > If you have two daughterboards you can send two independent signals.
> yes, I have two daughterboards(Basic TX). I can now send two independent 
> signals from the two daugterboards, but the two signals have the same 
> phase.
> 
> > 
> > If you start fresh from USRP power-up you can control the phase
> > between the transmitted signals (this also depends on the
> > daugherboards that you are using and how they are configured.)  
> 
> How can I control the phase on power-up?

IIRC, they come up with the same phase.

> The
> > power-up requirement is because from software we have no way to
> > control the phase accumulator in the AD9862 digital up converter,
> > however at power-up it has a constant value.
> 
> But if the two signals come out of the FPGA with different phase, 
> because each one of the signals will go to different AD9862. I would 
> think that the phase should be controlled from the FPGA and the AD9862 
> will have nothing to do with the phase, probably not :).

You can control the phase in the FPGA. However, we're using the
digital upconverter in the AD9862.  That DUC has its own phase
register.

Eric