Design o f Active F ilte rs Independent o f F irst - and Second - Order Operational Amplifie r T ime Constant Effects

A practical method of designing active filters in which the transfer function is independent of both firstand second-order operational amplifier time constant effects is presented. Neither matched operational amplifiers nor a tuning procedure dependent on an active parameter is required. The active portion of these filters is universal and readily integrable since it is comprised of conventional operational amplifiers and resistors. The method can be used to design a filter with any realizable transfer function of any order. Several new filters obtained from this method are introduced and evaluated both theoretically and experimentally. These configurations contain popular passive structures and the new universal active circuits. The significant improvements in filter performance of these new filters is demonstrated in this evaluation.