[time-nuts] Newbie questions

John Ackermann N8UR jra at febo.com
Wed Jan 6 02:17:53 UTC 2010


Tom Duckworth said the following on 01/05/2010 09:10 PM:
> Warren- No, a 100% error would be 40 GHz. Where did you get 40.4 GHz? 
> That would be 101% and of course 80 GHz is 200%.
> 
> Bruce- Of course you are right about the + symbol for 40.000 000 003 GHz 
> (+7.5 parts in 1E-11) but what would you consider current standard 
> notation. We still Use this metric notation in the US. What do you use?

In the *extremely* pedantic department, I think you would refer to "+7.5 
parts in 10e11" or to an offset of "7.5x10e-11".  When you're talking 
"parts in something" you use a positive exponent since you are referring 
to how large a population it takes to get 7.5 whole units.  When talking 
about fractional frequency offset, you use a negative exponent since 
you're referring to a fraction of a unit.  (There's probably a much 
better way to describe it.)

As I said, it's a very pedantic distinction...

John



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