Abstract :
A special case of the general feedback system in which a passive bilateral shaping network is used in the forward (¿) section and a unidirectional unit gain transformer in the return (Ã) path, thereby forming a positive feedback loop, is shown to be capable of acting as an operator network, i.e., of performing a prescribed mathematical operation on an input quantity. The set of possible circuit developments derived from the basic network includes certain previously published, but hitherto un-correlated, circuits. Application of localized negative feedback in the à section is used to hold the positive loop gain at unity thereby inhibiting instability. The method is compared with a more conventional arrangement using negative feedback.