[USRP-users] Frequency offset between two USRPs B210 synchronized with use of Octoclock-G
john.shields at xtra.co.nz
Fri Oct 6 18:12:43 EDT 2017
On 06/10/17 19:47, Piotr Krysik via USRP-users wrote:
> W dniu 06.10.2017 o 21:33, Piotr Krysik via USRP-users pisze:
>> Hello everyone,
>> I synchronized two USRPs B210 with use of Octoclock-G and the attached
>> gnuradio-companion flowgraph.
>> I've connected signal generator generating sinusoid to both devices (it
>> was on frequency 694.5MHz while USRPs were tuned to 694.3MHz, signal
>> power was about -40dBm). What I would expect is to see constant phase
>> offset between signals received by both USRPs (perhaps changing slightly
>> with temperature etc.). However what I see is constant changes of phase
>> that corresponds to frequency offset between two devices. Moreover this
>> frequency offset changes significantly from one execution of a flowgraph
>> to another (look at the image):
>> relative phase of two B210's
> Missing image of phase offsets in the attachment.
> Best Regards,
> Piotr Krysik
> USRP-users mailing list
> USRP-users at lists.ettus.com
While I have a slightly different h/w configuration
(2xN200, one GPSDO connected through MIMO cable (i.e. I use slightly
different time/clock sources; and 2 SBXs) and while I have modified the
Python code to use timed_commands per the ettus sync page , I have not
been able to get a consistent relative phase offset between the devices
on successive GRC runs. I have been struggling for quite a while -
hopefully, you will get a resolution quickly and I believe it might also
fix my problem!
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