[time-nuts] Cesium C Field Set?
bill at iaxs.net
Fri Feb 11 17:57:15 EST 2005
John responded to Brooke Clarke,
"> Anyone: When making a time interval mesurement what effect does an
> error in the counter time base have on the result?
I asked this question a few weeks ago and the answers I got are that as
long as the absolute time interval between start and stop is small -- in
the few us range -- the stability of the counter timebase won't matter
as its impact is imperceptible over such short intervals. But if you
get up into the milliseconds, it could have an impact."
We could get a little more quantitative about "impact" because there is
a relationship between the number of digits displayed and the number of
digits of accuracy. If you have an eight digit interval counter then
10e-9 is enough accuracy. You can do that with the crystal in some
counters if it has been calibrated, but your external standard certainly
has enough accuracy.
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