[time-nuts] New topics (was Re: He is a Time-Nut Troublemaker....)

John Ackermann N8UR jra at febo.com
Tue Dec 23 17:57:59 UTC 2008


Magnus Danielson wrote:

> This diffrential locking technique could be applied to atomic standards, 
> but then naturally require much improved solution than simple 
> oscillators. The diffrential locking technique does not magically solve 
> issues that is typically common mode, such as temperature dependence. It 
> can however even out individual properties like noise and systematic 
> drift to some extent. It essentially runs the oscillators as a common 
> constellation and attempts to achieve the average improvements of those 
> oscillators in an interlocked fashion. In its simplicity it will do 
> unweighed averaging. It is fairly easy to do weighed averaging by 
> individualizing the feedback gain to the respective oscillators. Further 
> refinements would individualize the proportional and integrate feedback 
> terms, but as always, the simplicity forms a limit.

Assuming that the atomic standards are correct for some tolerance of 
"correct", I'm not sure why you would need to use a differential locking 
scheme (or anything else that moves one oscillator versus the other) -- 
if you simply mix the two signals together you get a sum that contains 
both signals.  Apart from redundancy (what if one unit fails), why not 
just use that sum to drive the clock?

John



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