Recently I created a Matlab program for making Allan deviation measurements using Agilent's 53230A universal counter called "Stability Analyzer 53230A." The program performs true Allan Deviation measurements using the 53230A's gap-free sampling capability. The program provides an "All Tau Analysis" plot of the Allan deviation calculations. The Allan deviation calculations made are based on an array of Tau values you as the user provide. A second plot is also done of the measurement data that features time on the x axis and frequency on the y axis. All of the measurements and Allan deviation calculations can be accessed from the Matlab's command line after the program runs for further analysis. It is a great easy to use program for doing general frequency stability measurements on oscillator, clocks, and amplifiers.
The program uses LAN to connect and control the 53230A. All you need is the 53230A's IP address to connect. The program requires Matlab's Instrument Control Toolbox package to be installed. You can make the measurements on any of the 53230A's channels including channel 3, the optional microwave channel. This give you the ability to make stability measurements all the way up to 15 GHz. The "Stability Analyzer 53230A" program is free to download from Matlab Central (link below). In the downloaded program folder there is a Word document with operating instructions.
Below are two plots from an example run of Stability Analyzer 53230A (double click to enlarge). The example signal used was a 10 MHz signal with 0.1 Hz of frequency modulation added to simulate a cyclic disturbance such as temperature cycling. We can easily deduce the frequency of the cyclic noise in either plot. In the Allan deviation this is clear because we see dips at tau value 10s which is equal to the period of the noise and 20s which is an integer multiple of the noise's period. In the second plot we can see the time domain shape of the noise (sine) and its period.
To download the program from Matlab Central click here
To learn more about the 53230A universal counter click here