[time-nuts] Sample "R" script for ADEV under Linux wanted

[Bob Stewart]

"That code, like most ADEV calculations, assumes you have phase data..."

In my case, the phase data wraps at each DAC change.  Do I need to unwrap it, or change it to delta values?  I haven't read enough about ADEV to get a feel of what I want, or what this group means when someone say ADEV of xx.  I suspect that I need phase deltas from sample to sample to get the allan deviation of the phase changes?  Since mine wraps, I'm not sure if an ADEV even means anything.

Bob





>________________________________
> From: Tom Van Baak <tvb at LeapSecond.com>
>To: Discussion of precise time and frequency measurement <time-nuts at febo.com> 
>Sent: Sunday, February 2, 2014 10:23 PM
>Subject: Re: [time-nuts] Sample "R" script for ADEV under Linux wanted
> 
>
>>I suggest to use the TVB's
>> http://www.leapsecond.com/tools/adev1.c
>> C source and derive your script from it... but first, your GPSDO has
>> to put out the time interval error samples or you have a reference and
>> a TIC to measure your GPSDO (better this last setup).
>
>Correct. That code, like most ADEV calculations, assumes you have phase data, and so it uses the "x" form of 
>the formula. If the data is period or frequency then you use the "y" form of the formula. See: http://www.wriley.com/paper2ht.htm for details on both equations.
>
>See also: http://leapsecond.com/tools/adev_lib.c which computes ADEV, MDEV, and HDEV from phase.
>
>/tvb
>
>