✘0.250ppm/°C

Achim Gratz Stromeko at nexgo.de
Mon Nov 7 20:28:27 UTC 2016


Gary E. Miller writes:
> Yeah, I still arrive at tthe same opinion.

You are free to keep it.

>>  This data was for 86400 raw PPS
>> timestamps (which you are seemingly not recording), you are talking
>> the loopstats.
>
> Correct.  I care about the end result.  But when I look attt my raw
> data I actually see worse results in the unaveraged data.

You still mistake the loop offset for that end result you so vaguely
talk about.

>> So in fact I do get better numbers than yours at least at the tail
>> ends of the distribution.
>
> Facts not in evidence.

You've conveniently snipped those numbers so you can make it look like
none were provided.

> Please post ntpviz graphs and stats.

I gave you the statistics you've asked for and are now ignoring.  I
simply don't run ntpviz.

> Yuu think you are seeing xtal aging in 24 hours?  I seriously doubt it
> and you'll need a lot longer data collection to prove it.

You might want to read a whitepaper or book on how crystals age, there
is a choice of more than a handful you can just download, from all the
usual suspects.  Or maybe you don't want and keep your opinion.  Either
way is fine with me.

For your convenience, NIST defines "Aging is the systematic change in
frequency with time due to internal changes in the oscillator." (that
was proposed to become an IEEE standard in 1992).

http://tf.boulder.nist.gov/general/pdf/979.pdf

What you're seeing here is most likely caused by stress relaxation
(thermal hysteresis), since the long-term aging actually goes the other
way.


Regards,
Achim.
-- 
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