Capacitance Reduction in Active RC Synthesis†

Abstract

ABSTRACT Low impedance levels in a network and/or small values of significant time constants lead to large total reactance values in passive RLC realization and in the presently available active RC realization techniques. This paper presents active RC techniques for significant capacitance reduction in such problems. One method is suitable for basically ‘all-pole’ transfer functions, in which any number of left half-plane poles may be simultaneously realized with one low-gain amplifier and a passive RC L-type network. The transfer function is, however, quite sensitive to variations in active and passive network parameters, In another technique, the transfer function is synthesized by means of a cascade of second-degree canonic sections, isolated from each other. Two types of canonic sections are presented and optimized with respect to a figure of merit (R i+ R o) C t, ASA T consisting of the product of the sum of source and load resistors, total capacitance, required gain and system sensitivity to gain va...