Re: [Discuss-gnuradio] USRP2 phase drift

[Matt Ettus]

On 07/26/2010 03:26 PM, senlin peng wrote:
> Hi Matt
>
> > Even if you lock the USRP2 to an external reference, there will still be
> > drift relative to other things not connected to the same reference.
>
>
>
> Can you give me an example? The PLL on the daughter board is also
> connected with the reference clock.  I hope to know which part is not
> connected to the reference clock.

ALL of the parts are locked to the reference clock.



> The error has the same trend for all satellites. So I think the error
> is not caused by the clock difference between the local clock and the
> GPS clock.
> Is there any method that I can decrease the phase drift in the USRP2 output?


You are seeing REAL phase shift between your reference and the signals 
you are looking at.  Atomic clocks are good but nothing is perfect.

Matt