No subject

Begin forwarded message:



From: Hal Murray <_hmurray at megapathdsl.net_ (mailto:hmurray at megapathdsl.net) >
Date:  October 16, 2008 15:40:12 PDT
To: Discussion of precise time and  frequency measurement 
<_time-nuts at febo.com_ (mailto:time-nuts at febo.com) >
Subject:  Re: [time-nuts] Frequency Stability of Trimble  Mini-T
Reply-To: Discussion of precise time and frequency  measurement 
<_time-nuts at febo.com_ (mailto:time-nuts at febo.com) >







We have done some extensive research trying  to correlate jumps to


external phenomena (radiation, vibration,  thermal effects, etc).


There is no straight forward  correlation.



It's similar to asynchronous switching  inside a digital computer.


You can add levels of flip flops to  synchronize across two


asynchronous time-domains,  ...


I think that's  misleading in two ways.

First, we  understand metastability.  We can measure it and predict it.  It  
it 
mattered, we could test each individual  part.

Second, the failure mode is  exponential in a parameter we can control.  So 
given a  particular set of parts to pick from, it's reasonable to make a  
design with a probability of error small enough so that  other things are 
much 
more  important.



If it absolutely, positively can't take any  hit, then some more work is  
involved


I would say that the  first step is to put a number on "absolutely,  
positively".

If you aren't  willing to take some risk, you won't get off the drawing  
board.



--  
These are my opinions, not necessarily my employer's.  I hate  spam.




_______________________________________________
time-nuts  mailing list -- _time-nuts at febo.com_ (mailto:time-nuts at febo.com) 
To  unsubscribe, go to 
_https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts_ (https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts) 
and  follow the instructions  there.


=




**************New MapQuest Local shows what's happening at your destination.  
Dining, Movies, Events, News & more. Try it out!      
(http://local.mapquest.com/?ncid=emlcntnew00000001)