Synchronization and demodulation programming projects to accompany a first course on digital communications

This paper describes a series of programming assignments associated with a first course on digital communications. The programs build upon one another and progress toward an innovative final programming project that is completed during the last six weeks of the semester. Using black-and-white (1 bit per pixel) images as the message bits to be transmitted, the instructor synthesizes a set of modulated signals that are subject to different types of impairments including amplitude variations, carrier phase and frequency offsets, data clock phase and frequency offsets, additive Gaussian noise, and combinations of these impairments. Students write signal processing receiver algorithms including automatic gain control, and carrier recovery and timing recovery phase locked loops. Students apply their programs to the signals created by the instructor and recover the images. This project helps students internalize concepts taught during lecture sessions.