Two-electrode ECG measurement circuit using a feed forward CMRR enhancement method

Abstract

Electrocardiography (ECG) signal is currently recorded using minimum three electrodes, two electrodes for differential measurements and the third one to increase the Common Mode Rejection Ratio (CMRR). This paper presents a method to increase the CMRR of the analog front-end of ECG circuits. It is shown that the CMRR of ECG systems can be improved significantly without the need to the third electrode using a feed-forward method. It is also shown that the implemented ECG circuit can outperform the conventional right-leg driven systems when the signal paths are matched. The presented scheme can also be used with the right-leg driven circuit to further improve the CMRR.