[time-nuts] GPS phase lock !!

[Dan Sawyer]

I am new to time-nuts, and have just successfully phase locked a Jupiter 
GPS 10kc signal to a 10 mhz vcxo. There is jitter in the 10kc Jupiter 
output, as expected. How can the characteristics of the 10 mhz vxco 
signal be measured or analysed? A 10 mhz signal from a tcxo shows a 
clean sync with the locked 10 mhz signal, however there is low frequency 
'jitter' between the two signals. The 10 mhz signal gains and looses 
over about a 40 nsec range on a random 20 to 40 second cycle.

What is the root cause of this low frequency oscillation? Is it the 
result of the phase lock 'searching'? Or is it inherent in the 10mhz 
tcxo output?

Thanks in advance - Dan