[ntp:questions] Re: Use of "Atomic Clock" Nomenclature

Ulrich Windl Ulrich.Windl at RZ.Uni-Regensburg.DE
Fri Jan 20 13:36:18 UTC 2006

"Max Power" <mikehack at u.washington.edu> writes:

> Use of "Atomic Clock" Nomenclature

For further confusion, in Germany we have two words, like nuclear and atom:
Clocks are usually "atomic clocks", while power plants are either "atomic
power plant" (Atomkraftwerk), or "nuclear power plant" (Kernkraftwerk),
depending on which political party is currently active (I guess).

Strictly speaking, there's no clock without atoms, so just like an "iron
clock" or "plastic clock", the are all "atomic clocks", right? ;-)

What makes me nervous on the subject is that some vendors leave the
imagination that their receiver has the same accuracy that the remote
reference clock (less than a second in some hundred years). Most people do not
know that stock DCF77 receivers just turn on the receiver once to a few times
per day to save battery power. This makes the issue worse.

P.S. Now try to take your declared "nuclear clock" into a plane to the USA and
see what will happen ;-)

> Many WWVB RCC products are labelled (on the product itself or in the 
> documentation) as "atomic clocks." This is probably seen by manufacturers as 
> a useful marketing tool intended to capture the imagination of potential 
> customers, and some might argue that it is appropriate since atomic clocks 
> are located at the  WWVB radio transmitter site.
> However, we contend that use of the term "atomic clock" is technically 
> incorrect and misleading to consumers, and its usage should be avoided. 
> Unless there is actually an atomic oscillator inside the RCC (such as a 
> cesium or rubidium oscillator), we recommend that the term "radio controlled 
> clock" be used to correctly describe the product.
> Labelling products or documentation with the term "atomic timekeeping" is 
> also considered acceptable. 

More information about the questions mailing list