✘0.250ppm/°C

[Gary E. Miller]

Yo Achim!

On Mon, 07 Nov 2016 21:28:27 +0100
Achim Gratz <Stromeko at nexgo.de> wrote:

> >>  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.

Vaguely?  No, I'll just let my data speak for itself:

	https://pi.rellim.com
	https://pi2.rellim.com
	https://pi3.rellim.com
	https://pi4.rellim.com
	https://rellim.com

When you have data that looks better, no matter how you get it, I'd
like to try to replicate.

> >> 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.

None useful.  Seemed like cherry picking to me.  Please provide ntpviz URLs
so we can compare apples and apples.

> > 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.

Very few stats, with no backup.  See above.

> > 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.

Been there, done that.  If you have one that shows 'reversible aging'
please send the link.

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

Then it is not aging, is it?  I never said 'thermal hysteresis' was
not an effect.

But this is all arguing hwo many angles dance on the head of a pin, unless
and until you can get the end results of NTP (loopstats) looking better.

I have long thought the signal processing in ntpd was sub-optimal.  I
suspect there are changes in there that would help a lot, see if you can 
find one and share.  Then we ccan try to replicatet.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
	gem at rellim.com  Tel:+1 541 382 8588
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