The composite active filter: A combined wave-active and gyrator-C filter

With two inverting or noninverting active hybrid networks in a wave structure, wave-active, filters can be constructed without the need for additional inverting amplifiers. One-to-one correspondence exists between the dynamic elements of the active and passive networks. The hybrid has one bidirectional and two undirectional ports. Tandem connection at the undirectional ports leads to S-parameter realizations such as the ladder. Series and parallel connections at the bidirectional ports, while not strictly wave-active, can be used to reduce the number of amplifiers or to derive realizations for such networks as parallel ladders. Gyrator- realizations in which the gyrator is a loop of an inverting and a noninverting hybrid become a special case of the composite filter. Experimental results show agreement with the analytic conclusions and confirm the low sensitivity.