A new technique for the implementation of programmable-Q MOSFET-C filters

A new technique for the implementation of programmable-Q MOSFET-C filters is introduced. The technique uses 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. In addition, the center frequency omega /sub 0/ of the filter is also programmable via DC voltage controlled transconductance elements. An interesting connection between programmability, design automation, and physical layout of analog integrated circuits is discussed. The application of this technique to a second-order biquad filter is presented, along with computer simulation results.<>