[time-nuts] Data Collection for Allan Deviation

Poul-Henning Kamp phk at phk.freebsd.dk
Sat Aug 1 17:10:27 EDT 2015

In message <1925117252.232793.1438455428192.JavaMail.yahoo at mail.yahoo.com>, Bob Stewart writes:
>Hi Poul,

>"0)  Make sure that the counter does not get its reference frequency
>    from any of the input signals."
>Does your rule 0 hold if one of the input signals is a Cs standard? 
>I believe I've posted in the past that the ADEV from 1 tau to 100
>tau is a bit noisy if I use the internal 10811 to clock the 5370A. 
>I noticed the same on my 5335A.

For me it is a rule of principle:  If the HP5370 is clocked from the
same source I'm measuring, I can have no expectation of a well
behaved noise from the triggers.

The "noise" you saw is probably exactly that:  Overly optimistic
results if you clock the counter from one of the DUTs

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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