Teaching communication systems with Simulink and the USRP

Abstract

This paper discusses a system to demodulate and decode radio signals in real-time using the universal software radio peripheral (USRP) in combination with Simulink in an undergraduate teaching environment. Several previous papers have shown the value of using real world radio signals to inspire and motivate students in traditional communication systems courses and laboratories. Recent versions of Simulink now support a direct connection to the newer versions of the USRP, and Simulink can connect to the original USRP1 through an existing open source software package. This capability allows users to rapidly prototype radio systems that run in real-time on the host computer, which enables more realistic and interesting projects, laboratory experiments, and demonstrations. To illustrate this capability, a Simulink model is presented that implements a real-time FM radio that demodulates and plays the audio signal, and it also decodes the digital Radio Data System (RDS) signal and prints out the RadioText messages which usually convey the name of the artist and song that is currently playing. The use of this receiver as a demonstration in an undergraduate communication systems course is discussed, and its effectiveness is assessed. The source files for this receiver are available for free from the author. © 2012 American Society for Engineering Education.