[time-nuts] Frequency comparison vs. Parenting...
Burt I. Weiner
biwa at att.net
Sun Feb 7 19:28:21 UTC 2010
Calibration and precision frequency comparison is a lot like
parenting; It's an ongoing process that never ends.
Burt, K6OQK
>From: "Bob Camp" <lists at cq.nu>
>Subject: Re: [time-nuts] Frequency comparison
>
>Hi
>
>The rubidium *should* be good at the 1x10^-11 level. The GPSDO can be better
>than that. The issue is that neither one is very good in the short term.
>Measurement periods of hours are not unusual to get things right. If GPS
>with your antenna location is good at the 10 ns level, that's 1x10^-8 per
>second. 10,000 seconds will get you to 1x10^-12. That's good enough to
>calibrate the rubidium. The calibration standard should always be much
>better than the thing you are calibrating.
>
>No matter what you do, it's a "watching grass grow" sort of thing. Some sort
>of automation is a good idea.
Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California U.S.A.
biwa at att.net
K6OQK
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