[time-nuts] GPSDO disciplining algorithms
hmurray at megapathdsl.net
Mon Apr 13 21:41:02 EDT 2015
csteinmetz at yandex.com said:
> There are two regimes a GPSDO must deal with -- normal operation, and
Is there a 3rd regime: Recovery from holdover?
How many GPSDOs even spec what they do in that area? They may do it
indirectly by reference to Telco spec xxxx. What do the telco/cell-phone
I think there are two cases: good frequency and good time.
Suppose while it was in holdover, it drifted 1/4 cycle. Do you jump back to
the right phase/time as fast as possible or stay close to the target
frequency and creep back slowly? What is the expected frequency offset
Suppose it drifted 3 1/2 cycles. Does the PPS skip those 3 cycles so the
crystal only has to slew 1/2 cycle, or does the system slew the whole
distance so that a downstream counter stays in sync?
These are my opinions. I hate spam.
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