On 08/05/17 14:48, rickman wrote:


You aren't making sense. The reference is never adjusted in a PLL.
That's why it's the *reference*.

Just where did I say that ?. Having worked with pll's since the
4046 and earlier, I should know the difference.



In a pll, there is continuous feedback from the vco to the phase
detector, closing the loop and keeping the phase offset constant,
The phase is continuously updated every cycle, whereas the Shortt
clock can have significant accumulated error in the time between
corrections...

There is no requirement in a PLL for continuous action or even frequent
action.


That's probably why the Shortt clock is described as a hit and miss
system and correction is unipolar, whereas a classic pll continually
updates the vco every cycle, not multiples thereof.

Ok, the Shortt clock is probably as close as you can get to a classic
pll using mechanics :-)...

Chris