[ntp:questions] .1 Microsecond Synchronization

Terje Mathisen "terje.mathisen at tmsw.no" at ntp.org
Thu Jun 4 17:33:58 UTC 2009


John Hasler wrote:
> ScottyG writes:
>> Has anyone had any experience doing this? Can anyone suggest how to
>> achieve this accuracy?
> 
> Talk to the very long baseline radio astronomers.
> 
>> We do have some budget but this but if I need to spend a whole lot on
>> this I need to get in front of my management with the reasons.
> 
> You will need to.  Has someone already gotten in front of them with the
> reasons for this accuracy?
> 
> Of course, recording timestamps with 100 nanosecond _precision_ is easy.

That is probably the real requirement:

Windows' os clock runs with 100 ns ticks, but the actual resolution and 
accuracy is normally 10-17 ms.

That said, yes you can get down to sub-us timestamps, but it requires 
dedicated hardware to do so:

First you must have a timing-optimized gps receiver, then you need some 
hardware which can be slaved to the pps signal from that gps, and which 
can also be used as the time base of all your logs.

I.e.a PCI card or similar which your apllications can query directly to 
get the current timestamp.

Terje
-- 
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"




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