[time-nuts] My Casio G-Shock watch and other fun stuff

[Neon John]

On Thu, 21 Jun 2007 05:57:37 -0400, shoppa at trailing-edge.com (Tim Shoppa) wrote:

>Neon John <jgd at johngsbbq.com> wrote:
>> I don't quite understand why they'd all run so close during the day after a
>> sync but drift so fast if a sync was missed.
>
>In a typical disciplined oscillator timeclock, the predicted error goes
>like the square of the time since the last lock. "Next day" is probably
>6 to 12 hours after the 2AM time sync. Two days later is 30 to 36 hours.
>36 squared is 9 times bigger than 12 squared, so the predicted error
>would be 9 times bigger for the day after a night where sync was missed.

That probably explains it.  I suspect that Cassio does discipline the oscillator.
When it's getting a sync every night it stays so close that it almost has to.

John
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