A concept of time-varying FIR notch filter with non-zero initial conditions based on linear Kalman notch filter prototype

In this paper a digital FIR notch filter used for removing power-line interference from biomedical recordings is presented. A concept of finite impulse response narrow bandstop time-varying filter with non-zero initial conditions, based on linear Kalman notch prototype filter, is proposed. In order to reduce the duration of the transient response of the proposed FIR notch filter, a parameter of the Kalman notch prototype filter is temporarily varied in time. Moreover, optimal initial conditions for the proposed FIR filter have been determined. The presented filters are tested using sinusoidal and EEG signal. Computer simulations demonstrate that the proposed time-varying FIR filters outperform traditional time-invariant FIR filters with initial conditions set to zero.