A general theory and synthesis procedure for low-sensitivity active RC filters

The fundamental requirements for low-sensitivity analog filter structures are shown to be the bounded-real (BR) property of the transfer function and its implementation by a structure that "preserves" the BR property for incremental changes in the parameters of the network. Using these properties, a low-sensitivity realization of any stable BR analog transfer function is developed. The final structure is in the form of a singly constrained analog activeRC"two-pair" implemented as a cascade of two-pairs where each two-pair is characterized by a lossless bounded-real (LBR) transfer matrix. The proposed theory is shown to include the class of low sensitivity wave activeRCstructures related to the doubly terminated lossless two-ports. The new theory has been verified by computer simulation.