Three-inputs single-output voltage-mode universal filter with orthogonal control using single commercially available IC

Abstract

In this study, a new electronically tunable voltage-mode second-order universal filter as a new application for commercially available IC named LT1228 from Linear Technology Inc is presented. The proposed filter with three-inputs and single output voltage uses single LT1228, two resistors and two capacitors, which is well suited for off-the-shelf implementation. The proposed filter can provide high pass (HP), low pass (LP), band pass (BP), band reject (BR) and all pass (AP) responses with electronic control of the quality factor (Q) and the natural frequency (ω0). The control of quality factor can be done without affecting natural frequency. The selection of filter response can be done without any critical passive component matching conditions and double gain amplifier circuit. A number of simulations based on PSPICE program are achieved in order to demonstrate the performance of the proposed filter.