A new Tow Thomas filter structure with programmable omegan and Q

Abstract

A new technique for the implementation of Programmable-Q and ωn MOSFET-C filters is introduced in this paper. The new technique employs nonlinear circuits in the feedback path of the filter, allowing the tuning of Q through DC control voltages. The resulting topology is fully compatible with MOS technology. The centre frequency of the filter is also tunable via DC voltage controlled transconductance elements. The application of this technique to a Tow Thomas filter is presented along with simulation and experimental results.