On the Relation of Circuit Theory and Signals, Systems and Communications
In signal processing, system theory, an in information theory signals are either complex valued waveforms or sequences of dimensionless complex numbers. The power of such signals is usually said to be the squared magnitude of these complex numbers. In an electrical circuit, power is always the product of voltage and current, both present at a port, i.e., at a pair of terminals. Here, the authors ask the question: what is the relation between signal power and physical power? There are special cases, where the two notions of power are strictly proportional and, therefore, no conflict occurs.