[time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

michael taylor mctylr at gmail.com
Sat Apr 9 23:46:05 UTC 2011


On Sat, Apr 9, 2011 at 6:48 PM, Mike S <mikes at flatsurface.com> wrote:
> At 05:03 PM 4/9/2011, Tom Van Baak wrote...
>>
>> A note on notation.
>>
>> That ISO convention...
> In what ISO spec/standard/??? is that convention given?

I suspect it is a EIA or JEDEC (or NEMA) standard or convention
perhaps. I don't recognize it as an ISO standard that I am familiar
with.


> I suspect it is strictly informal, as the convention violates the SI rules:
> "A multiple or sub-multiple prefix, if used, is part of the unit and
> precedes the unit symbol without a separator. A prefix is never used in
> isolation" - BIPM, SI Brochure, Section 5.1;
> http://www.bipm.org/en/si/si_brochure/chapter5/5-1.html

Americans can (and should) use and follow US NIST Special Publication
811 _The NIST Guide for the use of the International System of Units_
(2008 edition, web version 3.2) as a suitable guide to SI usage in
USA.

 <http://www.nist.gov/pml/pubs/sp811/>

Personally though I do find the US alternative (deka) spelling of the
deca prefix disconcerting, and prefer trying to avoid potential
ambiguity by using metre for the unit, to avoid being mistaken with
the meter device.

Unfortunately I don't believe that Canada's NRC-INMS has an equivalent
document readily available.

Just so long as I don't have to deal between US "customary" and UK
"imperial", I'm pretty easy going.

-Michael



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