Active nonreciprocal realisation of the compact symmetrical network for transfer-function synthesis

Abstract

The well known method of realising a prescribed short-circuit transfer admittance function or open-circuit transfer impedance function (having real- or imaginary-frequency poles with unspecified associated driving-point immittances) as a compact symmetrical lattice is applied to a nonreciprocal form with the advantage of avoiding the lattice-to-ladder conversion problem. An example is given of an open-circuit transfer impedance function having real-frequency poles, requiring LC elements, which (if ideal transformers are ruled out) needs a smaller total amount of L or C than its reciprocal equivalent. In the RC case, Ozaki presented a method of realising a compact symmetrical network in the form of two parallel passive RC networks without the need for the intermediate lattice form. Accordingly, comparison is made between the nonreciprocal and Ozaki's method; two examples are given—one minimum-phase, the other non-minimum-phase—for both of which the nonreciprocal method is found to require substantially fewer passive components.