[time-nuts] A question from a newbie

Daniel H. Pressler dpressler at dandydan.net
Fri Nov 2 14:07:43 EDT 2018


Tom,

   Thanks so much.  I downloaded both the suggest software packages and they
look excellent.  It appears to me that my Arduino with phase comparator
should be a data collection only environment since these programs seem to
have all the whistles and bells I'm looking for.  I would appreciate
anything you might have in QBASIC as well.  That will save me from the
challenge of refreshing my C code skills.

   Again, thanks so much.  This was exactly what I was looking for.

Respectfully,


Daniel H. Pressler, KF2HP



-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces at lists.febo.com] On Behalf Of Tom
Van Baak
Sent: Thursday, November 1, 2018 9:54 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] A question from a newbie

Daniel,

There's simple C code at http://leapsecond.com/tools/adev_lib.c that does
ADEV / MDEV / TDEV / HDEV.
A sample ADEV program using that code is:
http://leapsecond.com/tools/adev1.htm

There are Python versions on the web if you're into Python and its
ecosystem.
If you want a QBASIC version let me know.

The only thing you need to watch out for is that there are two forms of the
ADEV formula. The "x" version takes phase difference as input. The "y"
version takes fractional frequency difference as input. You can convert one
to the other with differentiation or integration.

Since your old GPIB and basic days there are some very nice tools that take
all the pain out of ADEV now.
One is Stable32, highly recommended. [1]
The other is TimeLab, also highly recommended, especially if this is your
first time doing clock statistics interactively. [2]
Both have extremely well-written and informative documentation, worth
reading even if you don't use the programs.

/tvb

[1] http://www.stable32.com/
[2] http://www.ke5fx.com/timelab/readme.htm


----- Original Message ----- 
From: "Daniel H. Pressler" <dpressler at dandydan.net>
To: <time-nuts at lists.febo.com>
Sent: Thursday, November 01, 2018 3:05 PM
Subject: [time-nuts] A question from a newbie


>I was directed to this group when I asked this question of another group.
> However, after reading some of the emails I am a real novice when it comes
> to this stuff.  I worked with cesium and rubidium oscillators as Primary
> Reference clocks in the telecommunication industry.  When I was there I
> wrote a basic program to retrieve phase offset between two signals over
GPIB
> from a counter.  The program then calculated frequency accuracy and did
some
> Allan Variance calculations.  I am trying to replicate that with an
Arduino
> and a simple phase comparator.  I have forgotten the math and I am not
smart
> enough to glean it out of the data presented on the internet.  Can someone
> point me to some example programs that will allow me to measure phase
offset
> over time and calculate frequency accuracy and do some basic Allan
Variance
> calculation.
> 
> 
> 
> Thanks,
> 
> 
> 
> Daniel H. Pressler, KF2HP
> 
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