[ntp:questions] NTP with GPS and RTC
kostecke at ntp.org
Fri Apr 26 16:33:49 UTC 2013
On 2013-04-26, Biebaut Sven <sven.biebaut at be.thalesgroup.com> wrote:
>ATTRIBUTION MISSING said:
>>Biebaut Sven wrote:
>>> If I drop the idea of the RTC as a reference clock, am I correct in
>>+ stating that, when there is no external synchronisation:
>>> - my local clock and my RTC will drift away from each other, but at
>>+ least my RTC will be closer to the mark (the DS3231 is chosen for its
>>Probably not. ntpd will continue to apply first order frequency
>>correction to the local clock.
> Ah, I did not realise that. So a system with ntpd but without an external
> reference clock would still be more accurate than a system without ntpd
> at all ?
Only if ntpd has had access to a real local reference clock, or to
remote time servers, for a long enough period of time to calculate the
frequency correction. And the ambient conditions and system load match
that which existed when the correction was determined.
Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/
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