Volterra series analysis of intermodulation distortion in second-order active filters

The nonlinear performance of second-order active filters using single and two operational amplifiers at high frequencies and/or large-signal levels is investigated. A general procedure using the Volterra series is presented to allow comparison of different filter types regarding intermodulation distortion, and to provide means for improvement. Experimental and theoretical results compare favorably, demonstrating the accuracy of the analysis technique. It is shown that intermodulation distortion for single amplifier filters is much larger than for two-amplifier circuits.