NyquistGui (Nyquist Graphical User Interface) is a Matlab program designed to help to understand Nyquist Plots.  It is not meant to be an accurate, flexible tool for creating Nyquist diagrams; if that is what you are looking for, use Matlab's "nyquist" command.  The gui has two basic "modes," one for learning about the process of mapping from one domain to another (i.e., from the "s" domain to the "L(s)" domain).  Once you have a good understanding of the mapping process, you can choose to learn about using the Nyquist plot to check for system stability. A brief (4 minute)video follows that shows how to start the program, and describes its major controls.

Get the Files

To run NyquistGUI, you need two files,

You should put these files in a directory in the Matlab path so that Matlab can find them.  After that you just need to enter "NyquistGui" at the command prompt.

System Limitations

The system has several know limitations: