[time-nuts] FE-5680A Mechanical Question
jimlux at earthlink.net
Fri Jan 13 17:42:29 EST 2012
On 1/13/12 2:33 PM, Chris Albertson wrote:
> On Fri, Jan 13, 2012 at 2:19 PM,<EWKehren at aol.com> wrote:
>> Are we not overdoing it. 7E-13 for $15 KISS, and if you want to go beyond
>> that use a $ 30 analog version.
>> Looking right now at 1 E -14, I do se temperature influences, with my heat
>> sink stable to .1 C. Mainly due to the fact that is only one side of the
>> unit and it is clearly designed to use all sides for heat dissipation.
> Technical question, how does one measure 1E-14 changes in frequency?
> I'm thinking about building a controller and of course you can't
> control what you can't measure. But at that small level what do you
> use for a reference?
Your other sources. Seriously..
Of course, the man who has two clocks doesn't know what time it is.
If you have 3 sources, you can do three cornered hat type measurement
comparisons, for instance.
Typically, you might have clocks of various kinds. For instance, a nice
quiet quartz oscillator has great phase noise, but does drift with time
and temperature. So you could use that to measure the phase noise of
something with not so hot performance.
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