[time-nuts] How do you minimise jitter?

[Bruce Griffiths]

Don Collie jnr wrote:
> I`ve been puzzling over the reasons why one synthesised signal generator produces more close-in noise than another,
> and thought that one of the reasons for this noise would be jitter on the digital signals applied to the phase detector producing FM sidebands from the VCO. What then are the causes of jitter in digital circuits? A poorly regulated PSU to the logic might cause the hi/lo decision Voltage to vary, and this, combined with finite rise, and fall times, could cause jitter, but what are the things a designer can do to keep jitter to a minimum? Could the group comment please.
> ...............................................................................Don C.
> PS : I apologise if this question is a bit off topic, but minimising jitter is also important to precise time and frequency measurement [as is reducing close-in VCO sideband noise].
>   
Don

A frequency divider will alias the wideband phase noise of a VCO to 
frequencies close to the divider output frequency.
Thus differences in the phase noise floor of the VCO can manifest as 
differences in close in phase noise.

Bruce