A single-parameter adaptive comb filter

The study is concerned with a single-parameter adaptive comb filter (ACF), a multi-notch filter with periodically located nulls. The filter is suggested to retrieve a waveform modeled by superposition of harmonics, in particular, a periodic non-sinusoidal signal. Using trigonometric constraints between the signal fundamental frequency and overtones results in a nonlinear estimation problem. The adjustment relies on the extended Kalman filter. Particularly, the 2, 3 and 4 notch ACF are derived and tested under different conditions. Given a multitone scenario, the ACF significantly outperforms the common adaptive multi-notch filter.