txipi/AllanJS

AllanJS: Frequency Stability Analysis library for JavaScript

AllanJS

Frequency Stability Analysis library for JavaScript

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.

How to use it

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/.