[time-nuts] Difference between HP 5370A and 5370B

Had had at to-way.com
Fri Apr 15 19:25:46 EDT 2005

I have to agree with Brooke. I have both the 5370B and SR620 and I like the 
620. I will admit to using the 5371A every once in awhile.


At 04:13 PM 4/15/2005, you wrote:
>Hi David:
>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!
>Have Fun,
>Brooke Clarke, N6GCE
>w/Java http://www.PRC68.com
>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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