[time-nuts] Clock quality: alternatives to ADEV

Hal Murray hmurray at megapathdsl.net
Wed Apr 9 18:38:43 EDT 2014

I've been watching the discussions and graphs for a while.  ADEV seems 
appropriate for cases where the noise pattern is "nice".  How does ADEV work 
if the noise isn't nice?  Are there alternatives?  What's the mathematical 
term for the type of noise that works well with ADEV?

I can think of 3 examples:
  Crystal jumps
  GPSDOs going into holdover.
  Power lines make all sorts of interesting not-quite jumps.

Is there a way of characterizing that sort of event?  How do I turn a pile of 
data into a useful graph or chart?

What does an ADEV graph look like if the data has crystal jumps?

I'd expect that something like crystal jumps would follow some sort of power 
law: the bigger jumps would be less frequent.  But it wouldn't surprise me if 
the GPS or power lines had an underlying mechanism that turned into a 
different pattern.

These are my opinions.  I hate spam.

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