[time-nuts] Allan variance by sine-wave fitting

Attila Kinali attila at kinali.ch
Wed Nov 22 19:12:09 EST 2017


On Wed, 22 Nov 2017 15:38:33 -0800
Ralph Devoe <rgdevoe at gmail.com> wrote:

> To focus on the forest instead of the trees:  The method uses a
> $300 student scope (Digilent Analog discovery- a very fine product), which
> any skilled amateur can modify in a weekend, and produce a device which is
> 10-100 times better than the expensive counters we are used to using.  The
> software contains only 125 lines of Python and  pretty much anyone can
> write their own. In practice this device is much easier to use than my
> 53132a.

That's true. Such a system is increadibly easy to use.
But you can as well go for something like the redpitaya.
Because its architecture is ment for continuous sampling
you can do all the fancy stuff that Sherman and J├Ârdens
did. And thanks to GnuRadio support, you don't even have
to write python for it, but can just click it together using
the graphical interface. How is that for simplicity? :-)
An I know someone from NIST is actually working on making
a full featured phase noise/stability measurement setup
out of a redpitaya.

Oh.. and what I forgot to mention: I know how difficult it is to
do a proper uncertainty and nooise analysis of least-squares of sines.
I tried it last year and failed. There is lots of math involved that
I haven't mastered yet.


			Attila Kinali


-- 
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
facts that needs altering.  -- The Doctor


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