A first-order universal filter including a grounded capacitor and two CFOAs

Abstract

A first-order universal filter comprising two current feedback operational amplifiers, and processing merely voltage signals is presented. This filter can simultaneously produce all-pass (AP), low-pass (LP) and high-pass (HP) filter responses. LP, HP and AP filters possess high input impedances. HP and AP filters enjoy adjustable gains and low output impedances. A non-ideality analysis is performed for the AP filter. Nevertheless, the AP filter suffers from one passive component-matching problem. A quadrature oscillator and a multiphase sinusoidal oscillator obtained from the presented AP filter are offered. Based on the SPICE program, many simulation results are included. Moreover, numerous experiments based on commercially available active components are achieved.