[time-nuts] Data Collection for Allan Deviation

Poul-Henning Kamp phk at phk.freebsd.dk
Sun Aug 2 02:13:57 EDT 2015


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In message <1502052008.304624.1438465781711.JavaMail.yahoo at mail.yahoo.com>, Bob Stewart writes:

>Here's an example of what I'm talking about.  See description and
>notes.  The blue trace is the one using the clock in the 5370A. 
>The other tests match pretty closely down to around 60s or so.
>
>http://evoria.net/AE6RV/5370A/Test1.png

As a general principle:  Until you know why they differ, always trust the worst measurement
rather than the best measurement.

The "waves" on the blue line could indicate a spur which is not at
a multiple of your basic sampling frequency (1Hz)

-- 
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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