Real-time FM radio for teaching DSP and communication systems

Abstract

In digital signal processing (DSP) and communication systems courses much of the material is theoretical. There are some students who are more motivated to learn if they can see a connection to the real world, but unfortunately many real-world communication and DSP systems are very complex, and including them as part of a course is difficult or impossible. The FM radio, however, is a relatively simple system that is in some ways ideal as a real-world example because it includes both analog and digital signals. The analog signals transmit the audio and the digital Radio Data System (RDS) signal transmits auxiliary information such as the name of the artist, song, current time, etc. This paper describes an FM radio with RDS decoder based on an inexpensive FM module and an affordable DSP board. The system runs in real-time, demodulates FM radio, plays the music through speakers, displays the name of the song and artist, and allows access to the internal signals. This real-time receiver can be used in demonstrations in a lecture course or as the basis for a series of laboratory experiments.