Software for Teaching and Learning

This demonstration package addresses fundamental concepts in signal and systems, including poles and zeros, frequency response, impulse response, and difference equations. Relationships between time and frequency domain signals are fundamental to all aspects of this demonstration.

This demo runs a digital notch filter in real-time, processing signals from a microphone input. A slide whistle is quite useful for generating inputs, as it can be easily adjusted towards the notched center frequency.The tabbed windows in the lower left of the display are updated in response to changes in the slider positions. A variety of "What If..." may be posed to students, asking them to predict one filter representation, given another.

The design of this digital filter is straight forward, accomplished via the method of 'pole/zero placement'. Zeros are placed on the unit circle to eliminate a given center frequency, and poles are located at the same orientation - with a given radius. The center frequency and pole radius are specified using sliders.

Download Audio Notch Filter Demonstration

Learning Objectives

The following learning objectives are associated with the above demonstration, with supporting lecture and possible programming assignment.