[time-nuts] ergodicity vs 1/f
Magnus Danielson
magnus at rubidium.dyndns.org
Sun Dec 17 19:42:42 EST 2017
Hi
On 12/18/2017 01:03 AM, Bob kb8tq wrote:
> You then hit the very basic fact that a “standard noise process” does not cover what real oscillators or amplifiers
> do in the field. They have a *lot* of “noise like” issues that impact their performance. Simply coming up with a model
> for this or that process is only a very basic start to modeling a real device …..
Yes, indeed.
One does not have to be very esoteric. Temperature dependence is a very
systematic process, and we can kind of model a good part of its major
effects, but the "noise" of the temperature variations itself is not
easily covered and well, is a mess all in itself.
You then go downhill from there with gazillions sources of drift and
modulations.
We can however break some of the noise properties away and model them
and estimate their properties to some degree, so that helps get some of
the stuff understandable enough. The tools however is often widely
misunderstood and misused.
I just don't see how a lengthy debate on ergodicity is really helping
when doing it in the wrong end of things.
People does not even properly separate systematic effects from noise, so
their noise analyses becomes way of the mark and the systematic analyses
does not have proper confidence intervals. Then the discussing the color
of black does not help to understand the color of the orange very much.
Cheers,
Magnus
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