[ntp:questions] SNTP with 1ms of precision?

Richard B. Gilbert rgilbert88 at comcast.net
Fri Jun 18 16:55:13 UTC 2010


David J Taylor wrote:
> "Richard B. Gilbert" <rgilbert88 at comcast.net> wrote in message 
> news:fcGdnXzbxfVY7IfRnZ2dnUVZ_sadnZ2d at giganews.com...
> []
>> If you have a GPS timing receiver (different from navigation 
>> receiver), with a PPS output, one edge of that pulse should be 
>> accurate to within 50 nanoseconds.  A serial output will tell you 
>> which second is marked by the pulse.
> 
> .. although the very popular GPS 18x LVC specifies:
> 
>   "Accuracy: Measurement Pulse Output Time: +/- 1 microsecond at [the] 
> rising edge of the pulse."
> 
> so not quite as good as 50 nanoseconds.
> 
> Cheers,
> David

The difference is not significant unless you can somehow take advantage 
of the greater accuracy!  The difference in price between the Motorola 
device whose specifications I was citing and the GPS 18x LVC is quite 
significant; ISTR that I paid about $300 for mine.  If I had to replace 
it, I'd go with the GPS 18X LVC.





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