[time-nuts] How does sawtooth compensation work?

David davidwhess at gmail.com
Tue Jul 19 01:26:55 EDT 2016

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

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

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

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