Activity and Stability of Linear Networks

The stability criterion of linear four-terminal networks is given in a compact form similar to the activity criterion. The reduction of the Llewellyn criterion [2] to this new form is presented. By means of the stability and activity criteria in their compact form, an activity-stability diagram is derived, which is shown to be useful in the analysis of nonreciprocal networks, indicating stability, activity and nonreciprocity, and in the field of synthesis of nonreciprocal, passive and active networks. The new insight that is gained, indicates a novel way of achieving nonreciprocal stable amplification, using reciprocal active elements such as tunnel diodes and varactor diodes