Time-discrete networks

In this letter, the authors pose an interesting area of study which, it is felt, will lead to a clarification of the relationship between network theory and system theory. Specifically, it is proposed that a formal study be made of networks of RLC components characterised by difference relations rather than differential relations. The main contribution is a set of definitions which preserve stability, passivity and other energy relations in the discrete-time case and which pass to the continuous time relations as the step size becomes small. The formalism introduced shows promise of providing a foundation for digital-computer network simulators.