A Teaching Tool for Understanding Different Audio Filters
Alireza Kavianpour, William Thin Nguyen, Paul Wagner · 2021
A teaching tool for understanding different audio filters is developed.Texas Instrument Digital Signal Processing (DSP) board, 16-bit Motorola micro-controller (MC68HC12), and C++ programming are used to develop a teaching tool for explaining different types of audio filters.One application of this tool is for eliminating audio feedback in a Public Audio (PA), or sound reinforcement system.An audio noise occurs when an input device (microphone) picks up its own signal from the output device (speaker) thus creating a loop.The result is a loud noise coming from the speakers.With the use of this system this type of problem will be eliminated.In this new tool, user through keypad can select a specific filter.The system then takes an incoming analog signal and converts it to digital form.The digital signal is then "scanned" using a Fast Fourier Transform Algorithm (FFT) to find the unwanted frequencies.These offending frequencies are then filtered out.Next the processed digital signal is converted back to analog and sent to the speaker.The system has the capability to display data in a graphic form.A simple procedure could be carried out to update the software and add more features like digital effects (delay, and pitch shifting).The ability to make these changes by this software package also makes expansion very inexpensive and affordable.Most importantly this system can be widely used for educational purposes.