How to use PEZ
By Craig Ulmer / grimace@ee.gatech.edu
PEZ Overview
PEZ, A Pole Zero Editor for MATLAB, provides a portable program designed
to help introduce some fundamental concepts about the Z-Plane. It provides
a means for manipulating the location of poles and zeros throughout the
Z-plane, as well as a tool for observing the various results found through
the system. The poles and zeros constructed in the Z-Plane can be exported
to other Matlab applications as a Filter transfer function.
Starting PEZ up
PEZ is a Matlab application, so the procedure for running PEZ is
fairly simple: boot up Matlab, make sure PEZ is in your path, and
simply type pez to start the program.
After the computer has had a few seconds to ponder your command, the
following window should pop on your machine.
As you can see there is a Z-Plane axis to the left in which you manipulate
poles and zeros. On the right half of the screen are controls for manipulating
the co-ordinates the objects you place in the Z-Plane. The menu bar for the
window contains options for saving,loading, and clearing your work. All of
the changes that you wish to make to the filter are performed through this
window.
When changes are made to the filter, a second window is generated to reflect
the new filter's responses. This window will look like:
The four panels in this window represent some of the responses for the filter
that you have created in the main PEZ window. From left to right, the plots
are:
- The Z-Plane Representation (Horizontal Axis=Real Portion, Vertical Axis=Imaginary Axis)
- The Impulse Response to the Filter
- The Magnitude of the Frequency Response (from -pi to +pi)
- The Phase of the Frequency Response (from -pi to pi)
The Basic Functions
The basic functions you have to work with in the PEZ main control window are: