[time-nuts] Allan deviation -> finally some data!!!

Didier Juges didier at cox.net
Thu Oct 26 20:09:33 EDT 2006

It seems obvious that's what hapenned, but I am still curious about the 
temperature variation. Must have been the coax cables difference in 
length going to the two inputs. Temperature affected the delay.

The resolution of the 5370 is quite amazing.

Thanks for the comments and the software.


PS: I have posted the test conditions yesterday or the day before.

Ulrich Bangert wrote:
> Didier,
> i am currently not aware exactly HOW this data was acquainted, but in
> Counter_Ti.Dat you surely measured the noise floor of your HP5370. The
> Allan deviation of 3.5 E-11 @ 1s matches exactly the 5370's specified
> 30-40 ps rms measurement jitter. 
> While this measurement does not say anaything about any oscillator
> involved you should make a print of it and glue it to your wall since it
> will show you the noise floor of your equipment. You will never been
> able to measure a Allan  deviation lower than this line for any Tau as
> long as the 5370 is involved. 
> That should give you a good indication for the fact that your equipment
> will not enable you to measure the Allan deviation of GOOD oscillators
> at low Taus. 
> 73 de Ulrich, DF6JB

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