On 01/03/2019 08:53 AM, Sivan Toledo wrote:
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.
The only thing i can think of is a setup error. Like not actually
requesting the time source be set to "external" for the B200 case.
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?
I think on the B200 "ref locked" refers to the external front-panel
reference in. BTW if you are using the external REF-IN on a B200/B210
you have to remove the internal GPSDO, due to electrical cross-talk
on the REF lines.
On Wed, Jan 2, 2019 at 7:53 PM Marcus D. Leech via USRP-users
<usrp-users@lists.ettus.com <mailto: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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