"EL" wrote in message
...
"Richard Henry" wrote in message
...

"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.

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.

*** GASP!!!!!! ***

An error of one part in 5,184,000??!?!?!?!?!

How could anyone possibly tolerate that???!?!?!?!?!

;^)

I recall working with a marketing guy a few years back who had a customer
interested in a ruggedized PC that had timing accurate to 1 second/month,
even when turned off. He thought the PC's real-time clock chip would be ok,
because it has its own battery.