Operational amplifier realization of the unitor concept

In a previous paper this writer postulated an ideal topological transmission element (unitor) and has shown in subsequent papers its conceptual value over the entire field of nonreciprocal network analysis and synthesis. Later writers have employed the nullor, which, in its threeterminal form, is externally equivalent to the unitor. Now that wide-band linear differential-input operational amplifier units are readily available in compact solid-state form, It has become practicable to obtain convenient and useful realizations of the unitor (or nullor). In this paper we give the basic circuit technique.