Jonathan Kirwan wrote:

On Fri, 24 Jun 2005 16:36:09 -0400, "DaveM"
wrote:

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?

Any advice would be appreciated.

Thanks a lot.

Darren Harris
Staten Island, New York.

[...]

I had thought that maintaining an accumulated deviation of no greater
than 1/60 sec in 6 hours is about like 24 seconds/year or 2 seconds a
month. This is 1ppm drift. Without being temperature stable, this
is not so easy, is it?

Jon

Just checking the math: 1/(6*3600*60)=7.716E-7

You are right. That may be difficult without an oven.

Darren's spec may be a little tight. Normally, people who need to measure to
that precision already know the methods and where to get the needed
equipment.

The next question : what is he measuring that is that stable? I don't know of
anything that is expressed in seconds with 1ppm stability, except perhaps
gps. But if it involved gps, he'd already have the answer to his question.

Mike Monett