A new generalized inverter based on the active hybrid

Abstract

SUMMARYThe building block for the new generalized immittance inverter is a 3-port known as the active hybrid network. One of its ports is bidirectional, and matches a design admittance yo. The second port operates in the send, while the third port operates in the receive direction. The hybrid is constructed from an op-amp and a 5-port network composed of a few resistors and the design admittance yo. There are two versions of the hybrid: the voltage-inverting (i.h.) and the noninverting hybrid (n.i.h.).The inverter consists of an i.h. and an n.i.h. connected at their unidirectional ports in a loop. The gyration admittances are actual driving-point admittances in the circuit, namely the design admittances yo, y b of the two hybrids. Such an inverter, when terminated at its output port by a load admittance y, will give at its input port an input admittance Expressions are derived for the y parameters of the inverter at higher frequencies, thus accounting for the finite bandwidth of the op-amp.Two special cases are particularly treated, and experimental results are obtained for them. The first is the case of the resistive gyrator, for which yo and y b are pure conductances. The second is the case of the capacitive gyrator, for which yo and yb are pure capacitive susceptances. The capacitive gyrator is used to produce the supercapacitor, or f.d.n.r., and the results of measurements on a number of f.d.n.r. networks are given.