[time-nuts] Weird TEC data

Hal Murray hmurray at megapathdsl.net
Sun Aug 7 00:13:49 UTC 2011

newell at cei.net said:
> The general shape and bumps in the plots track nicely, but I'm  wondering
> why there's so many cycles difference after 36 hours. 

How are you collecting the data?  What's the time between samples?

One possibility is that one system is picking up extra clock ticks.  If your 
data is dense enough, that should be pretty obvious if you zoom in on the 

Here is an example:
That's sampling every 10 seconds.

Glitches like that are easy to spot if you plot the frequency.  It's the 
difference in counts divided by the difference in times between a pair of 
samples.  At 10 second sampling rate, you get 600 counts per sample.  601 
counts turns into 60.1 Hz.  That 0.1 Hz is well above the noise.  (at least 
with my setup)

These are my opinions, not necessarily my employer's.  I hate spam.

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