[time-nuts] NTP Temperature Compensation

lists at lazygranch.com lists at lazygranch.com
Thu May 16 16:14:29 EDT 2013

Some sensing is done with a diode on a chip. Not exactly free air.

Back when nicads ruled, I did a bit of temp testing for battery packs. Free air thermistors have so little mass that air currents have significant influence. You would need some processing of the sensor data.

-----Original Message-----
From: "Jason Rabel" <jason at extremeoverclocking.com>
Sender: time-nuts-bounces at febo.com
Date: Thu, 16 May 2013 13:46:19 
To: <time-nuts at febo.com>
Reply-To: Discussion of precise time and frequency measurement
	<time-nuts at febo.com>
Subject: Re: [time-nuts] NTP Temperature Compensation

Since most modern PCs have at least one temperature sensor on the motherboard, I wonder if it would be possible to monitor that to
help compensate for temperature changes. I realize the locations of said sensor can be anywhere on the board, but you would think it
could help out *some* amount.

> i've seen that myself, NTP's compensation can almost be used as a way to
> measure room temperature.   You can see the AC cycles.   For this reason I
> keep the NTP server in a walk in closet that lacks heating duct.  The room
> temp cycles slowly.
> I've also read but can't remember where about a project to replace the TTL
> can oscillator in a PC with a better quality one driven from a OCXO.  That
> is a lot of work for small gain.
> One thing about that study.  I notice the author had t remove the PPS
> reference clock.   It looks like he was unabe to get the graph to move at
> all with PPS attached.   I'd like to see the same study done with a good
> PPS reference clock let connected.  Likely the results would be
> uninteresting, just a flat graph.

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