An approach to active filter design problems using gyrators: A fresh look

Abstract

Abstract The conventional approach to active filter design problems using gyrators has been to replace each individual inductor (grounded or ungrounded) of the passive filter by an active network using one or more grounded gyrators. The method fails to realize three terminal versions when the passive filter is itself a balanced one (four-terminal two-port(. Another approach is to replace the passive filter as a whole by an equivalent active network using gyrators. The transfer function as a whole is synthesized as an active network. This method makes possible the realization of three terminal versions of certain active filters which are not possible by the conventional method. The method has been illustrated for the cases of a driving-point impedance function and a constant resistance lattice filter. An all-pass transfer function has been synthesized as an example.