[time-nuts] Of rubidium life and piggy-bank anemia....

John Ackermann N8UR jra at febo.com
Sat Dec 1 16:14:56 EST 2007


John Ackermann N8UR said the following on 12/01/2007 04:07 PM:

> I use the 100 second average for two reasons:  first, it results in a
> somewhat better resolution than the 2ns native of the HP-5334A TIC,
> which may or may not be meaningful in the ADEV calculation given the PPS
> noise.  Second, it smooths the peak-to-peak noise, particularly from the
> GPS, and makes for smoother phase plots, particularly when one of the
> sources is GPS (I realize that 100 seconds isn't long enough to
> integrated out the GPS noise; when I do my long-term plots, I further
> reduce the data to tau = 1 hour and even tau = 1 day which is more
> meaningful).

By the way -- another reason I linger on each PPS pair for 100 seconds
is to slow down the wear rate on the relays in the 59503A switch!
They're good for millions of cycles, but why switch every 1 or 10
seconds when there isn't any measurement gain from doing so?  And, if
I'm going to sit in one place for 100 seconds, I may as well take 100
readings instead of just 1. :-)

John



More information about the time-nuts mailing list