[time-nuts] Updated Divider Jitter Results
magnus at rubidium.dyndns.org
Sat Apr 4 12:27:49 UTC 2009
Poul-Henning Kamp skrev:
> In message <49D740D1.1030600 at febo.com>, John Ackermann N8UR writes:
>> Sure. I didn't write down the numbers because it was an interim step,
>> but I earlier did that and IIRC the std dev was around 20-25 ps.
>> Would error in the cal circuit tend to falsely increase, or decrease,
>> the result? Or both?
> In my experience it generally skews your result downwards, but I have
> seen it move upwards also, it all depends on the phase.
I have seen how it skews both ways. With a very sensitive hand a minimum
can be found which can be fairly low, such as 13 ps but then I had tuned
the 200 MHz section carefully. Getting such low results on a general
signal is not possible. Also, the ref out of the HP5370 has a wideband 5
MHz signal with overtones noise which can be removed if modified.
Modifications requires one little short-out.
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