Overview

AllanJS is a Frequency Stability Analysis library for JavaScript.

A gentle introduction to Frequency Stability Analysis is provided by NIST Special Publication 1065, written by W.J. Riley.

Features

Data loading

Load phase or frequency data from an array.
Load phase or frequency data from file / URL.

Data preprocessing

Phase to frequency conversion.
Frequency to phase conversion.

Frequency Stability Measures

Maximum, minimum, mean and standard deviation for phase and frequency values based on averaging times (tau).
Original Allan deviation (ADEV).
Overlapping Allan deviation (OADEV).
Modified Allan deviation (MDEV).
Time deviation (TDEV).
Hadamard deviation (HDEV).
Overlapping Hadamard deviation (OHDEV).
Total deviation (TOTDEV).
Modified Total deviation (MTOTDEV).
Time Total deviation (TTOTDEV).
Hadamard Total deviation (HTOTDEV).

Plots

Phase data plot.
Frequency data plot.
Sigma-tau plots of Allan estimators.

Screenshots

Phase data plot:

Phase

Frequency data plot:

Frequency

Sigma-tau plot:

Sigma-tau

How to use it

Include AllanJS and Flot + jQuery:

<script language="javascript" type="text/javascript" src="js/jquery.min.js"></script>
<script language="javascript" type="text/javascript" src="js/jquery.flot.min.js"></script>
<script language="javascript" type="text/javascript" src="js/allan.js"></script>

Prepare a data array or file (one value per line):

var nbs = [ 
  8.920000000000000e+02, 
  8.090000000000000e+02,
  8.230000000000000e+02,
  7.980000000000000e+02,
  6.710000000000000e+02,
  6.440000000000000e+02,
  8.830000000000000e+02,
  9.030000000000000e+02,
  6.770000000000000e+02 
];

Create an AllanJS Dataset:

var allan1 = new Allan.Dataset('example 1');

Load data from array:

allan1.loadFreqFromArray(nbs);

Get Allan deviation values for tau = 1, 2, 4:

console.log(allan1.getAdev(1), allan1.getAdev(2), allan1.getAdev(4));

Get Hadamard deviation values for tau = 1, 2, 4:

console.log(allan1.getHdev(1), allan1.getHdev(2), allan1.getHdev(4));

Generate sigma-tau plot (it will be placed in a div with id='plot1'):

var plot1 = allan1.getSigmaTauPlot(['ADEV', 'HDEV']);

$.plot($('#plot1'), plot1.values, plot1.options);

Acknowledgements

This library is based on several Frequency Stability Analysis tools:

adev3, by Tom Van Baak http://www.leapsecond.com/.
allan, by Magnus Danielson http://rubidium.dyndns.org/.
Stable32, by William J. Riley http://www.stable32.com/.
TimeLab, by John Miles http://www.ke5fx.com/.

Plots are created using Flot, a pure Javascript plotting library for jQuery, by Ole Laursen http://code.google.com/p/flot/.

Download

Source code available on GitHub: https://github.com/txipi/AllanJS/downloads.