[time-nuts] Low cost synchronization

Mike Ciholas mikec at ciholas.com
Thu Aug 18 19:55:15 EDT 2005

On Fri, 19 Aug 2005, Dave Brown wrote:

> While a fascinating engineering challenge, I fail to see the 
> need for such accurate timing, given the typically wide ranging 
> timeframe for human response to similar signals -eg cell phones 
> ringing, etc. Or is it enough for the user to merely be aware 
> of the audible prompt? Is it possible to elaborate?

I can't go into details but suffice it to say that the 
requirements are driven by the parameters of the experiment and 
not from a technical requirement flow down.

Imagine passing out thousands of little devices, all them beep at 
predetermined times within some tolerance (a few seconds give or 

The precision comes not from the human response time so much, as 
to what happens when the devices come back together again.  It 
will be real obvious to people when they all go off at different 
times.  The "man with two clocks" problem.  We even thought of a 
low power peer to peer radio to synchronize any units in the same 
area to avoid this "oops", but that doesn't help for things like a 
phone call.

Mike Ciholas                            (812) 476-2721 x101
CIHOLAS Enterprises                     (812) 476-2881 fax
255 S. Garvin St, Suite B               mikec at ciholas.com
Evansville, IN 47713                    http://www.ciholas.com

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