Re: Wanted: A Very Accurate Timer

"John Fields" bravely wrote to "All" (29 Jun 05 13:45:16)
--- on the heady topic of "Re: Wanted: A Very Accurate Timer"

JF> From: John Fields <jfields@xxxxxxxxxxxxxxxxxxxxx>
JF> Xref: aeinews sci.electronics.design:25987
JF> sci.electronics.repair:51922
JF> On Wed, 29 Jun 2005 19:53:49 +0200, maarten@xxxxxxxxxxxxxxxxxxx wrote:

>In sci.electronics.repair Searcher7@xxxxxxxxxxxxx wrote:
>> I've got all of the answers I could get here.
>
>But have you read them? Apart from that you may not be able to interpret
>them, I know you got some useful advise. I suggested you use an 120Hz
>clock, so you will actually obtain the sampling resolution you want. I
>have not seen you respond to that, thankful nor rejective. For me that
>implies you should really find an electronics designer to work with.

JF> -!-
JF> For me, your suggestion that he use a 120Hz clock implies that you
JF> don't know what you're talking about.

JF> Considering that the OP has specified that: "It must to be accurate
JF> to within 1/60th of a second over the course of 6 hours."

JF> means that, since there are 3600 seconds in an hour there will be
JF> 21,600 seconds in six hours, and since he wants to split the seconds
JF> into 60 slivers each, there will be 1,296,000 slivers in six hours.

JF> Since he states that the accuracy must be _within_ 1 sliver, that
JF> means he needs an accuracy of one part in 1,296,000. Looking at it
JF> from a different perspective, that's an accuracy of +/- 0.000038580%.

JF> Now, what was it you were saying about that 120Hz clock?


John,

IMO, his apprehended requirement seems far too demanding for the task.
The original question was simply lacking in experience but that is no
crime for a novice. He is attempting to do in hardware what is a
trivial solution in software. Anyone who has toyed with simple
computer programming must at some time come across a program example
that attempts to guess at the timing of a keypress. They may have even
come across some that learn a pattern.

A*s*i*m*o*v

.... Hardware: The parts of a computer that can be kicked

.

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