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Re: SC's USB Clock

This project is supposed to synchronise with the Internet via a PC to

> ensure "accurate timekeeping" > > How accurate can it be, when any time signal derived via the internet > will be delayed by the unpredictable latency of the network ? > > The claimed accuracy in stand alone mode, running off a watch crystal > is 2 seconds a day. Are you really going to improve it by a daily > sync with the net ? I would have thought that all you will achive will > be to keep the clock in step with your PC and the net service from > which the PC's time is derived +/- the latency error. > > Any ideas ? > > Dave G

Any errors from network delays will only last till the next synch and if they are small will not matter. A 2 seconds a day error will be 1 minute a month because that error is cumulative.

John G.

Reply to
John G
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That's not how it work. Many network packets are sent to try to establish the latency and the variance, and the measured cumulative errors are used to form a corrective prediction against the local clock.

The network latency can be in the hundreds of milliseconds yet the result can be more accurate than that.

Reply to
Clifford Heath

It's not cumulative if you re-synchronise, that's the point of it.

Dave.

Reply to
David L. Jones

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