[ntp:questions] frequency adjusting only

Steve Kostecke kostecke at ntp.org
Tue Apr 22 13:42:45 UTC 2008

On 2008-04-22, maxime louvel <m.louvel at gmail.com> wrote:

> My goal is to achieve a synchronisation between the nodes (not
> with the public NTP server) within 50 usec.

You may want to explore other synchronization options such as IRIG,
distributed PPS, or a distributed 10MHz clock.

>I don't care if the synchronisation to the public NTP is accurate
>around half a second.

You're displaying a common misconception about NTP.

The goal of NTP is not explictly to synchronize clocks to "the one
true time". Rather, NTP synchronizes clocks to a common time base. A
"better" time base, and a "better" distribution method, allows tighter
synchronization between nodes.

It so happens that UTC (via GPS or HF Radio or UDP) is a ubiquitous,
stable, and relatively inexpensive time base. A side effect of using UTC
as your time base is that your clocks are synchronized to the correct

Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/

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