Electronically tunable current - mode universal biquad filter using Dual - X current conveyors

Abstract

In this paper, an electronically tunable current-mode (CM) universal biquad filter is proposed. The proposed filter employs three dual-X second-generation current conveyors (DXCCIIs), two grounded capacitors and four NMOS transistors acting as resistors. The proposed filter simultaneously realizes standard filter functions such as low-pass (LP), band-pass (BP), and high-pass (HP) responses. The notch (NH) and all-pass (AP) functions can also be obtained by connecting appropriate output currents directly without using additional active elements. The output signals are obtained at high output impedance terminals, which is important for easy cascading in CM operation. SPICE simulation results are given to verify the theoretical analyses.