[ntp:questions] Frequency Offset

Chris Albertson albertson.chris at gmail.com
Thu Feb 23 23:12:03 UTC 2012

On Thu, Feb 23, 2012 at 1:44 PM, Alby VA <albyva at empire.org> wrote:

>  When you say "crystals used to control the timing in computers",
> are you referring to the parts that make up my actual FreeBSD
> Server (ie: Motherboard)?  Or Parts in the GPS Device (ie: Sure Elec.
> GPS)?
> Or in the Satellites receiving the GPS signal?

The crystal on the computer motherboard.

At the most basic level, the purpose of NTP is to compute that offset
you see.  That is the offset between the clock on the computer's
motherboard and a perfect clock.    The offset value will change with
temperature.  Try watching it for 24 hours or maybe partially block
the computer fan and see what happens in an hour.  NTP keeps
recomputing the offset as your computer's clock changes with
temperature or just with age.

(I think you meant "Satellites  __transmitting__  the GPS signal")

Chris Albertson
Redondo Beach, California

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