To solve the problem that fetal electI·ocardiogram is difficult to extract when there are motlier electrocardiogram and fetal electrocardiogram coincidence in the time domain of maternal abdominal electrocardiography

a modified matched filtering method is proposed for coincidence detection. The method first preprocesses the signal

removes the baseline drift

enhances the mother's ECG signal and fetus ECG signal

introduces the average heartbeat to obtain the mother' s ECG QRS template signal

and combined with matched filtering method to extract the abdominal ECG coincidence wave. Finally

matched filter method combined with the mother's ECG R-peak position adjustment and the similarity calculation to obtain fetal ECG. The experimental results show that the accuracy of fetus electrocardiogram is 92% in the MIT PhysioNet / Cin C2013 database

which shows that there existed maternal ECG and fetal ECG coincidence wave in time domain. Compared with the traditional matched filter method to extract fetal ECG

the accuracy is improved.