[time-nuts] How to measure Allan Deviation?

Didier Juges didier at cox.net
Mon Oct 23 21:20:31 EDT 2006

Hi Ulrich,

comments are embedded:

Ulrich Bangert wrote:
> the Datum LPRO User's Guide / Installation Guide discusses some methods
> of sine to square wave conversion in terms of lowest phase noise. 
This is good to know. Do you have any suggestion how I might get a copy 
of the relevant pages of the manual?
> Since you were originally asking for Allan Deviation i would like to
> advertise again my free PLOTTER software which does what ALAVAR does but
> more nicely + many things more. Since it does not simply open the input
> file but first makes a copy to a "working file" you may even work with
> it on files in that a different program is currently sampling data, so
> you don't have to wait to the end of data acquistion but may get
> intermediate results at any time.
That sounds like a great feature, nothing worse than stopping a long 
test period just to see if the data is any good, even though I should 
get the same result by copying the log in progress in a temp file using 
conventional methods. Your program saves the step and makes it that much 
more convenient. I will download it. I will make sure my program does 
not buffer too much data before flushing to the file, so that I get as 
much of the data that is available for analysis.
> When you put forward your questions about measuring Allan deviation i
> saw that it were all the right & intelligent questions and perhaps this
> is the reason why so many people are willing to enlighten you. I wish I
> had known time nuts when i was in the same state of mind as you. Would
> have saved me years of learning it the hard way!
Thank you. I am amazed at the amount and quality of support I got. I 
intend to organize all the contributions in a web page. It seems like I 
was not the only one with these questions, but everyone else was afraid 
to ask :-)
> 73 de Ulrich, DF6JB
73, de Didier KO4BB

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