Hundreds of milliseconds, which I think imply that either the PPS is
arriving at a random time (not likely), or that the function that sets the
time at the next PPS actually sets it immediately.

Otherwise your assumptions about my setting is correct, an N200 and a B200
each with its own Ettus GPSDO.

I also noticed another thing that is strange, but maybe not the cause of my
problem; the ref_locked sensor returns false on the B200 (even after I do
all the procedure to set the clock at the next PPS) but true on the N200.
Maybe the B200 simply does not have that hardware feature to check? Or does
this indicates a problem?

On Wed, Jan 2, 2019 at 7:53 PM Marcus D. Leech via USRP-users <
usrp-users@lists.ettus.com> wrote:

> On 01/02/2019 05:37 AM, Sivan Toledo via USRP-users wrote:
> > Hi,
> >
> > I have a code that reads the GPS time and sets the time on the next
> > PPS using uhd_usrp_set_time_next_pps. The code is based on advice from
> > Ettus (we wait for PPS, wait 200ms, read the time, repeat 3 times, and
> > then set the time correctly for the next PPS after checking that there
> > are at least 200ms left in the second) and it works fine on N200 with
> > GPSDO.
> >
> > The same code causes trouble on B200 with the TCXO based GPSDO. The
> > GPS seems fine and we get a fix, and the code works fine, but the
> > clocks are not synchronized with those of N200s.
> >
> > Is there a known problem with this function on N200s?
> >
> > Thanks, Sivan Toledo
> >
> Just to clarify the picture here, you have an N200 and a B200, each with
> their own GPSDO.  You're trying your best to synchronize them
>    using the PPS pulse from their respective GPSDOS?
>
> What scale is the lack-of-synchronization?  Are we talking nanosecond,
> microsecond, millisecond?
>
>
>
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