Fundamental Structure of Input-Output Stability for Feedback Systems

An approach to the input-output stability of feedback systems is discussed. This approach incorporates the natural inverse operator model to describe these systems. Using this operator, the input-output stability problem is decomposed into five subproblems. One of these subproblems involves the causality of the input-output operator, a property not recognized in previous feedback system stability studies. Following the development of the model and the stability definition some general stability theorems are presented.