[time-nuts] another Ebay mixup, 5370

SAIDJACK at aol.com SAIDJACK at aol.com
Sun Jun 10 19:30:12 UTC 2007


In a message dated 6/10/2007 07:54:34 Pacific Daylight Time, didier at cox.net  
writes:

>scope). The top waveform is a little blurry because the two time  bases 
>are not phase locked, and I triggered on the  HP5370.
>http://www.ko4bb.com/Test_Equipment/HP_5370A/HP8657B-HP5370A.png
>I  also have a spectrum plot of the HP5370A ref  output.
>http://www.ko4bb.com/Test_Equipment/HP_5370A/HP5370A.jpg
>Didier


Hi Didier,
 
thanks for the pics! Yes, the signals almost look the same. Your 10MHz  
output is even a bit more noisy. On the Wavecrest set to Oscilloscope mode (it  can 
work like a normal high-speed scope) I see the small humps around the zero  
crossing appear and disappear quickly, so I think these are causing the  
modulation, and hence the >200ps jitter. Not a clean sine-wave for sure. I am  glad 
it's not just my unit.
 
To everyone: would my unit perform better with very(!) careful calibration?  
Is there any cal-lab that can do it inexpensively, and not mess up the unit (I 
 have had instruments returned to me after cal that were mistuned, and worked 
 less well than before)?
 
There are so many trimmer caps inside that for sure I am not going to move  a 
single one of 'em :)
 
Then again I get <50ps jitter with 8.2 readings per second using the  
external Ref input, so maybe I should be content with that. That's a lot better  than 
my 53132A.
 
Thanks again everyone for your useful hints!
 
bye,
Said



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