[time-nuts] Difference between HP 5370A and 5370B
brooke at pacific.net
Fri Apr 15 19:13:21 EDT 2005
There's an appendix in the Stanford Research manual for the PRS10 Rb
oscillator that explains how to make 1,000 measurements each second and
thus get 1 ps accuracy every second. It involves using a precision
external clock into the SR620 and connecting the Ref Out (1 kHz derived
from the internal or Ref oscillator) into the External Gate input. The
Start and Stop signals need to be something like 10 MHz, or probably any
frequency at or above 1 kHz. And the gate is used to enable a
measurement 1,000 times per second.
Each second you could see a drift of 1E-12 and 1E-14 in 10 seconds! I'm
going to try using this method to set one Cs standard to the one I think
is now set.
Note that some of the HP counters can display a large number of digits
per second when measuring frequency, BUT NOT in time interval mode.
I like the SR620!
Brooke Clarke, N6GCE
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
David Kirkby wrote:
> That counter sure was a pretty high-spec device in its day. I looked
> today in the Standford Research cataloge and they have the SR620
> but I note that has a 25ps single shot capture. I've not looked at the
> current HP (sorry Agilent) specs on this sort of equipment. . . . .
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