Signals and Systems
MIT Center for Advanced Engineering Studies built this distance-education course in 1987 for working engineers and scientists, and MIT OpenCourseWare offers the full materials free. It covers continuous-time and discrete-time signals and systems, developing representations in both the time and frequency domains and linking them through the Fourier transform and its generalizations. Lessons work through filtering and filter design, modulation, and sampling for analog and digital systems, along with feedback systems in both domains. The course includes video lectures, readings, and problem sets that build from basic signal representation toward practical applications in areas like communications, speech processing, and image processing. It suits anyone wanting a rigorous grounding in the mathematical tools that underlie modern electronics and signal processing, taught with MIT's characteristic technical depth.