Classification of signals and systems. Models of signals, signal spaces. Representation of signals by sets of orthogonal functions: complex exponentials, Walsh, Haar, Laguerre functions, wavelets. Short-time Fourier, Hilbert transforms. Transformations of narrowband signals by bandpass systems. Optimum filtering, matched filters, Viener, Kalman filtering. Spread spectrum signals. Nonlinear dynamical systems, chaos.