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 _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
