[ntp:questions] NTP on red hat 7.3, was precision can be expected
Richard B. Gilbert
rgilbert88 at comcast.net
Fri Jun 22 00:24:32 UTC 2007
> On Jun 21, 5:14 pm, "Richard B. Gilbert" <rgilber... at comcast.net>
>>>I'm trying to use NTP 4.2.0 with red hat 7.3 and a military GPS on a
>>>Pentium 1.4 Ghz board.
>>>If I compare the Linux Time with the GPS time using a oscilloscope.
>>>At start time I was getting a time difference of about 20ms then after
>>>6h linux time was 150ms ahead.
>>>Can i expect to have a time precision to +/-20ms whithout the PPS.
>>There's no way we can answer that without knowing more about the GPS and
>>how time is being transmitted to the Linux system!
> The GPS is connected through the serial port at 9600 bps
> And the ntp.conf is setup to read it.
>>WITH the PPS, you should have time good to within 50 nanoseconds or
>>better! Just how good it will be depends very much on how the interrupt
>>system works. If it's low latency, time will be very good. If not, not!
It's probably good to +/-20ms. Using the PPS is clearly several orders
of magnitude better.
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