[ntp:questions] TAC-2 internal delay

Brad Knowles brad.knowles at skynet.be
Sun Oct 19 08:20:45 UTC 2003


At 7:38 PM +0800 2003/10/18, test wrote:

>  So, the question I have is about the relevance of the 8ns receiver
>  delay.  Shouldn't it be closer to 1.3us, or am I just missing the
>  point completely?

	It strikes me that if all you want is true PPS, then none of this 
should be necessary.  The delays should be the same for each pulse, 
and since what you want is an extremely accurate pulse-to-pulse count 
of how much time has elapsed, then all the rest of that just drops 
out of the equation.

	Now, if you want an extremely accurate representation of the time 
(as the upstream device purports it to be), then you will need to 
know the delays, because you'll have to account for them when you 
finally get the data and parse the output.  But I would think you 
shouldn't need that for true PPS.

-- 
Brad Knowles, <brad.knowles at skynet.be>

"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety."
     -Benjamin Franklin, Historical Review of Pennsylvania.

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