Very-high-Q inductor simulation for active tuned filters

ABSTRACT Numerous circuits have been developed in the past for simulating inductors, using operational amplifiers and other passive components. Although some of these circuits can be shown to have ideally infinite Q factors, in practice the value may be limited by various stray and non-ideal effects. This note presents a modified gyrator circuit, in which the equivalent series resistance can be totally eliminated by simulation of a series negative resistance of equal value in the gyrator, resulting in a very high value of Q.