[time-nuts] crystal againg fit (was: Excel logarithmic function)

Attila Kinali attila at kinali.ch
Thu Nov 24 10:49:23 EST 2016

On Thu, 24 Nov 2016 08:16:08 -0500
Bob Camp <kb8tq at n1k.org> wrote:

> If you take the bad aging (out of spec) parts out of the pile, those are the ones
> with the best fit. They have very pretty curves and they stick to those curves
> for a *long* time. They have a single dominant cause for their aging ( = the defect). 
> The rest of the parts have all of the causes bashed down by the process so that
> over a 20 or 30 year span, there probably is no single dominant cause. 

Then the question becomes: What would be a good fitting function for
the typical application of an OCXO that is regularly measured with
not too long time spans (e.g. GPSDO)? From the discussion it seems
that a second or third order Taylor would be sufficient to capture
aging for a span of 10-100 days.

			Attila Kinali

It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
                 -- Miss Matheson, The Diamond Age, Neil Stephenson

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