[time-nuts] How does sawtooth compensation work?

[David]

On Mon, 18 Jul 2016 22:01:01 -0700, you wrote:

>> It would be interesting to look at the data to see if you can find the sort 
>
>Hi Hal,
>
>There's lots of examples of sawtooth patterns at: http://leapsecond.com/pages/MG1613S/
>
>In particular there's this monster: http://leapsecond.com/pages/MG1613S/tic-72-hour.gif
>
>It's simple for a microprocessor-based GPSDO with its TIC to realize when it's getting too lost in a hanging bridge. There are a number of ways around the problem. My favorite is gluing a resistor on top of the GPS chip and pumping a few tens of mW through it when you want the bridge to stop.
>
>Here's the proof-of-concept: http://leapsecond.com/pages/vp/heater.htm
>
>/tvb

Universal timer/counters and equivalent time sampling DSOs can have
this problem when their timebase ends up synchronized with the signal
they are measuring.  Some carefully modulate their timebase to prevent
this.

When I was testing my Garmin 18x against my Racal-Dana 1992, I could
see it happen when the outside temperature was just right.