Realization of Resistorless and Electronically Tunable Inverse Filters Using VDTA

摘要

This paper presents resistorless realization of inverse filters using voltage differencing trans-conductance amplifier (VDTA). First, four topologies are proposed which provide inverse low-pass, high-pass, band-pass, and band-reject responses. Subsequently, a unified inverse filter is also derived by incorporating two switches in the combination of proposed inverse low-pass and inverse band-pass topologies. This topology is capable of providing inverse low-pass, inverse high-pass, inverse band-pass, and inverse band-reject responses by appropriate switch settings. The proposed inverse filter structures are electronically tunable and use only grounded capacitors. The behavior of the proposed filters is also investigated for nonidealities. To verify the functionality of the proposed inverse filter circuits, SPICE simulation is carried out using 0.18-mu m CMOS technology parameters from TSMC. The effect of deviation in the active and passive component values on angular frequency is tested through Monte Carlo simulation.