[ntp:questions] Re: announce: NTP FAQ v3.8
David J Taylor
david-taylor at invalid.com
Fri Jan 21 10:46:43 UTC 2005
Ulrich Windl wrote:
> Alain <alainm at pobox.com> writes:
>> Some questions:
>> - in Section 3.3 it says: "Some of the best clocks available still
>> have errors of about 1E-8 PPM" Is this really 1E-14 ?
> 1E-8 Parts per Million are 1E-14 parts. Right?
> Like 1E-1cm is 1E-3m.
Mixing numbers like that is very confusing. My personal feelings are that
if you use PPM, then the units should be whole numbers: 15 PPM, 2 PPM
etc, certainly /not/ fractional parts. If you must use fractions, then
not more than one decimal place - 1.6 PPM, 0.3 PPM If you need to express
smaller quantities, just stick with scientific notation 1E-12, 1E-14 etc.
Clarity of communication is very important.
Even better, of course, where you can use superscripts to write 10-12,
10-14 (but not in this plain text e-mail!).
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