[time-nuts] Is there a good web page introducing ADEV?

[Bill Notfaded]

Good evening Hal-

I found a pretty good one from Rakon.  I'll attach it here.  It was one of
the better descriptions I've seen.  They also make some of the best current
manufactured new what I would call Oscilloquartz/Brandywine BVA
replacements the HSO14.  Lots more good docs on their website under:

http://www.rakon.com/products/technical-resources/tech-docs

Bill

On Thu, Sep 24, 2020, 2:02 PM Richard (Rick) Karlquist <
richard at karlquist.com> wrote:

> Another great post, Tom.
>
> Amplifying Tom's last paragraph:
>
> 1.  The statistics of clocks are (take your pick)
>
> a.  Not gaussian, central limit theorem doesn't apply
> b.  Not stochastic
> c.  Not stationary
> d.  Not ergodic
> e.  Contain flicker of frequency processes that do not
> average to zero; AKA 1/f noise.
>
> IOW, most of what you think you know about statistics doesn't
> apply.  For example, "variance" is undefined because "mean" is
> undefined.  It is important to get inside Dave Allan's head in
> terms of why he invented this in the first place.
>
> 2.  Many poorly informed practitioners are in denial about the
> above and resort the measures known as "jitter" or "wander".
> These further muddy the water.  They are IMHO, even more difficult
> to understand than ADEV.  They have their place (a very narrow one)
> but should be disregarded if you want to understand ADEV.
>
> 3.  Unlike phase noise, ADEV is a fairly non-intuitive concept.
> While there are methods to convert phase noise to ADEV, you
> can't go in the other direction.
>
> You sometimes hear the phrase "this is not rocket science".
> Well in the case of ADEV, it IS rocket science (or at least
> rocket statistics).
>
> Rick N6RK
>
> On 9/24/2020 12:35 PM, Tom Van Baak wrote:
> > Hi Hal,
> >
> > ADEV turns out to be pretty hard to understand. I took me years for it
> > to sink in. There are web pages, articles, even books. Part of the
> > problem is matching the explanation with the audience.
> >
>
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