On 08/03/17 17:27, rickman wrote:


Not sure if you are referring to the Shortt clock or the PLL. But the
statement applies equally to both. There is no magical stability in the
PLL. It is a control loop and as such the thing being controlled will
*never* remain in phase or at the same frequency as the reference.


I think the difference is that while a pll always has a phase offset
the reference and vco are in phase lockstep once the loop has aquired
lock. It's a closed loop system whereas the Shortt clock is an open
loop system, only getting a kick back into sync from time to time.

Like a hit and miss governor ?...

Chris