Hi Sylvain, W dniu 22.09.2017 o 11:44, Sylvain Munaut pisze: > Hi Piotr, > > > And do you set both the Clock and Time source to the external ones > when using it in that configuration ? I think I have written this at least twice before. I will try again to describe it again as clear as I can. Recipe to reproduce the problem: 1. take a USRP B210 with GPSDO inside, 2. connect external source (i.e. Octoclock-G) of PPS and 10MHz ref to it, 3. set sources of PPS and 10MHz ref to "external", 4. record sinusoid, 5. look at the sinusoid's phase (one simple solution is to uwrap phase, fit first order polynomial to it and remove it from the original).
> I just had a look at both the schematic and VHDL and there is actual > switches ... the GPSDO 10M and PPS should basically be completely > disconnected when the reference for time and clock is external. I suppose they are not enough. Anyway problem with combo of USRP B210 equipped with GPSDO and Octoclock-G was confirmed yesterday by mixbit on usrp-users list (he said they have it in their bug tracker). > Also, are you using an external power supply ? Maybe the issue is the > added load on the supply rails when the GPSDO is plugged in. > External supply doesn't help. Only removing GPSDO from USRP B210 helps. Which is not bad. p.s. Now we are fighting with frequency offset between two USRPs B210 synchronized with octoclock. It causes phase drift of about 1 degree/second, and changes with time. When I will know more I will describe it in a new thread on the mailing list. Best Regards, Piotr Krysik _______________________________________________ USRP-users mailing list USRP-users@lists.ettus.com http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
