Application of the adaptive impulse correlated filter for recovering fetal electrocardiogram

A method is described for obtaining the fetal ECG from surface electrodes using a procedure that combines averaging and adaptive techniques. The algorithm proposed consists of an adaptive filter whose reference signal is an impulse synchronized with the maternal QRS and whose desired signal is a fetal abdominal derivation. The filter behaves as an exponential average whereby its weights define an averaged abdominal maternal pulse that can be subtracted from the original register, thus eliminating the maternal contribution and securing a clean fetal ECG.