Fully integrated universal biquads using operational transresistance amplifiers with MOS-C realization

Universal biquadratic filters employing operational transresistance amplifiers are presented. All 5 different second-order filtering functions, namely low-pass, high-pass, band-pass, notch, and all-pass, can be realized. The quality factor of the filters can be adjusted electronically without affecting resonant frequency. The configuration can be made fully integrated based on MOS-C realization, by making use of the current differ- encing and internally grounded inputs of OTRA. PSpice simulation results are given to verify the theoretical analysis.