[time-nuts] PRS-10 findings

SAIDJACK at aol.com SAIDJACK at aol.com
Wed May 30 15:38:48 EDT 2007


 
Hi Tom,
 
>Can you refresh me on the topic? I didn't see any 
>PRS10 humps  here:
>http://www.leapsecond.com/museum/prs10/




We had a discussion about this, and some other folks did see it also.  
Sometime around June last year or so, I need to dig up my measurements.
 
>Just to get a clear idea of your lab set up; how is your  counter
>configured exactly; int or ext ref? trigger levels? 1X or  10X
>attenuation, etc.


I am using the PRS10 as the external reference to the 53132A. Maybe not a  
good idea? I will try another reference as well.
 
Also, one more datapoint: I changed the phase relationship away from 80ns,  
and the problem seems to have gone away... I need to check into this  further.
 
Maybe it's related to the absolute phase difference between the two  channels?

>If you can see the readings on the 53132 display, do they  also
>happen when your PC (RS232 or GPIB?) is not  electrically
>connected to the counter? Desktop or floating  laptop?


RS-232, floating laptop, I get the same readings on the LED and  RS232.

>Is the Fury floating (wall wart) or are you using a  grounded
>power supply? How is the PRS10 powered? etc.


The Fury wall-wart is also floating, but the PRS10 is grounded. But I think  
the periodicity of exactly 15s would indicate some sort of digital issue 
rather  than analog ground loop etc, wouldn't it?

>Also do the 10 MHz RF outputs show this phase jump or is  it
>only in the 1PPS outputs?


Need to check that.
thanks again for your feedback,
bye,
Said

/tvb







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