[time-nuts] PLL behavior

[Jim Lux]

I'm looking for info on behavior of a PLL (with VCXO) when the reference 
comes and goes periodically. When the reference is gone, the PLL will 
"flywheel" according to whatever the loop filter does. (we can turn off 
the "input" to the filter, so we're not trying to track noise)..

What I'm particularly interested in is the behavior in the PLL when the 
reference returns.

The overall situation is where we are trying to make a frequency/phase 
measurement over 10-100 seconds, where the reference has a 50% duty 
cycle, and is on for a second, off for a second.


I can fairly simply model this, or just try it, but I'm looking for some 
references to an analytical approach.