This Topic considers four different types of deterministic signals, namely continuous-time periodic signals and non-periodic signals, and discrete-time periodic and non-periodic signals. The Topic considers basic properties of each of these classes of signals, and places a special focus on the appropriate frequency transform method and spectral representation for each of these signal classes. Key observations of the spectral properties are highlighted, including the duality principle. This Topic covers background material that will be used throughout the rest of this course, and there are no associated self-study questions.