An Adaptive Filtering System for Separation of Cardiac and Respiratory Components of Bioimpedance Signal

This paper presents an adaptive filtering system for separation of two bio-impedance signal components: cardiac and respiratory signals. The proposed filtering system is adaptive to the parameters of the input signal´s cardiac component (the reference signal), which is corrupted by the respiratory component and also by additive stochastic disturbances. The adaptation is achieved applying estimation and continuous tracking of the heart rate using a time-optimal adaptive phase-locked loop (APLL). Technical solutions of the filtering system are oriented on applications in portable and implantable medical devices