[time-nuts] Phase, One edge or two? (was Digital mixing with a D Flip Flop)

Hal Murray hmurray at megapathdsl.net
Wed Oct 22 17:57:47 EDT 2014


tvb at LeapSecond.com said:
> 2) For long-term analysis, even 1 PPS is overkill. Having more data may not
> improve your oscillator drift plot at all. This is because the frequency is
> a moving target. Ever more precise measurements of a moving target are
> wasted; they don't add any clarity to the overall trend. Consider measuring
> a 10811 for a year. Do you need to follow its phase or frequency every 100
> ns? Or second? Or minute? Maybe as little as one data point per day is more
> than enough to make a perfectly accurate long-term frequency drift plot. 

You need more than 1 sample per day for ADEV plots left of 100,000 K seconds.

Suppose you have lots and lots of data at, say, 1 second samples.  You can 
turn that into an ADEV plot.  Does anybody scan the data in clumps, say a 
day, to see if the short-tau picture changes over time?


-- 
These are my opinions.  I hate spam.






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