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On Fri, 24 Jun 2005 10:50:57 -0700, "Richard Henry"
wrote:

"Jim Thompson" wrote in message
.. .
On 24 Jun 2005 17:19:09 GMT, Ian Stirling
wrote:

In sci.electronics.design wrote:
Can I get recomendations for the most accurate electronic timer that I
can buy?

It must to be accurate to within 1/60th of a second over the course of
6 hours.

Is something like this commercially available, or will I have to build
it, or have someone build it?

GPS recievers.
I've seen some with an alarm function.
However, 1/60th of a second in 6 hours isn't impossible to do otherwise.

An ordinary digital clock powered from the AC line is more accurate
than that.

On the surface, shouldn't that be "as accurate as that"? In North America
and other 60-Hz realms, at least.

As I understand it, for grid-power-hopping to work, the accuracy is
_much_ better than that.

I have heard horror stories about short-term inaccuracies in the power
system 60 Hz timing, that it is only guaranteed to be accurate within 1
cycle per day, for instance.

I think that's nonsense.

And I found this tidbit googling around for accurate clocks: "GPS time was
zero at 0h 6-Jan-1980 and since it is not perturbed by leap seconds GPS is
now ahead of UTC by 13 seconds."

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
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