[ntp:questions] ATOM falseticker with flag3 enabled

David Lord snews at lordynet.org
Sun Apr 1 14:56:17 UTC 2012


David J Taylor wrote:
> "David Lord" <snews at lordynet.org> wrote in message 
> news:t1bk49-6hi.ln1 at me6000g.home.lordynet.org...
> []
>> I'm not sure which value you are referring to. From the
>> "ntpq -p" billboard over a day, I see values of jitter
>> of the GPS as low as 0.002
>>
>> jitter  No of
>>          0.002    156
>>          0.003     50
>>          0.004     22
>>          0.005      4
>>          0.006      4
>>          0.007      1
>>          0.012      1
>>          0.014      1
>>          0.025      1
>>
>> "ntpq -c rv" for that system reports "precision=-19". ie 2^-19,
>> but another couple of systems without PPS source are reporting
>> "precision=-20" and I think that these two systems have done
>> better than that when temperatures have not been as varied.
>>
>>
>> David
> 
> Feel the need for more than 3 digits here?

Not at the moment. Changes due to temperature variation
are about 30us, which is 15x the lowest figure of 2us I
have for jitter.

An oven controlled or temperature compensated system
clock source would be required to take advantage of the
already existing digits.


David




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