Definition of signals, systems and networks. Classification. Causality, linearity, invariancy. Basic operations on discrete time (DT) and continuous time (CT) signals. Time domain description of DT and CT systems. Impulse response, convolution, input-output (BIBO) stability. State space description, response calculation, asymptotic stasbility. Signal flow networks (SFN). Frequency domain description. Sinusoidal signal, phasor representation. Canonical SFN representations. Nyquist and Bode plots. Periodic signals, Fourier series. Fourier transform, distortionless signal transmission. Complex frequency domain description. Transfer function, pole-zero pattern. Laplace transformation. Special (allpass, minimum-phase FIR) systems. DT simulators of CT systems.  (5 credits)