Current-mode universal filter with four inputs and one output using CDTAs

A current-controlled multiple-input single-output current-mode universal filter employing current differencing transconductance amplifiers (CDTAs) as active elements is described. The proposed circuit offers the following attractive features: employment the minimum number of active and passive components; simultaneous realization of all the standard filtering functions; independent current-control of the parameters ω0 and ω0/Q; no requirement of component matching conditions; employment of only two grounded passive capacitors which is suitable for integrated circuit (IC) implementation; and low passive and active sensitivities. ©2006 IEEE.