An adaptive analog notch filter using log filtering

Abstract

An adaptive analog notch filter is proposed for applications requiring high frequency adaptive signal processing. Based on a log filter circuit topology, this filter design suggests new circuitry for the implementation of analog adaptive filters. Simulation results demonstrate that the filter is capable of rejecting a sinusoid, and with a second notch filter section attached, is capable of rejecting a pair of sinusoids. The circuit design and the adaptation method are described.