✘0.250ppm/°C

[Gary E. Miller]

Yo Achim!

On Mon, 07 Nov 2016 20:01:46 +0100
Achim Gratz <Stromeko at nexgo.de> wrote:

> Gary E. Miller writes:
> > Hard to control the power dissipation on a PC serving the
> > internet.  
> 
> We weren't talking about a PC, or at least I was not.  The only
> subject I'm discussing is a rasPi and more specifically the 2B, which
> has multiple cores to play with.

I consider RasPi's to be PCs, powerfull little machines.  I use my 
RasPi's exactly as I use my other 'PC's.

> >> 99% of all
> >> PPS timestamps over the last day stay within ±10µs, 75% within ±1µs
> >> and slightly less than half within ±500ns.  
> >
> > Odd that I get much better numbers without all that work:  
> 
> Read again what I wrote, please.

Yeah, I still arrive at tthe same opinion.

>  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.

> So in fact I do get
> better numbers than yours at least at the tail ends of the
> distribution.

Facts not in evidence.  Please post ntpviz graphs and stats.  I'm not
gonna go rouund and round with vague assertions instead of data.  Here
are many of mine:

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

> The skew seems to originate from the aging transient (especially the
> initial part, see below),

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.  There may
be 'initial' aging just after you cut a crystal, but not it sees
a small transient, what you are seeing is loop convergence.  Aging is
by definition irreversible.

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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