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

[Bruce Griffiths]

John Ackermann N8UR wrote:
> 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
>
>   
John

Deadtime issues only arise if one combines successive 100 second
measurements separated by (N-1)x100 seconds.
Finite relay lifetime is an issue if one is logging for months or years
on end.

Bruce