FDCCII-based electronically tunable voltage-mode biquad filter

In this work, a voltage-mode biquad filter realizing low-pass, band-pass and high-pass characteristics is presented. The proposed filter, which employs two FDCCIIs, two grounded capacitors and two NMOS transistors, provides electronic tunability with the control voltage applied to the gate. NMOS transistors act as linear resistor. Furthermore, the proposed circuit still enjoys realization using a low number of active and passive components, no requirement with the component choice conditions to realize specific filtering functions, high input impedance, and low active and passive sensitivities performance. Simulation results using SPICE program are given to show the performance of the filter and verify the theory. Copyright (c) 2010 John Wiley & Sons, Ltd.