Analysis and simulation modeling of programmable CFOA-based universal filters with CMOS digital potentiometers

In this paper the proposed configuration of a digitally controllable non-inverting RC integrator, employing 4-terminal CFOA is an object of analysis and simulation modeling. Based on a theoretical analysis of the circuit the equations for the transfer functions and formulas for the related electrical parameters are obtained. By using the synthesized circuit of an integrator a programmable CFOA-based universal filter with CMOS digital potentiometers connected as variable resistors is developed. The proposed filter can generate basic biquadratic filtering functions namely: low-pass (LP), band-pass (BP), highpass (HP) and band-reject (BR). The validity of the filter is demonstrated by simulations and experimental test of sample electronic circuits, working up to 2MHz with THD<;1%.