Interference Reduction and Common Mode Rejection in Electrocardiograph Signal by Removing the Ground Electrode

Rejection of common mode voltages in biosignals is a crucial issue specially in acquiring electrocardiograph (ECG) signal susceptible to a significant interference due to the surrounding sources of noise. The identification and minimization of these common voltages and sources of interference are necessary to acquire such signal because its level is low (few millivolts) compared with these undesirable common voltages generated by the surrounding environment. We investigate different sources of interference and common voltages coupled to an ECG signal and analyze techniques to reject and mitigate their effects. We propose the elimination of the ground electrode and study its efficiency to reduce common-mode voltages and improve the rejection ratio of the bioamplifier. We provide a qualitative ECG signal acquisition with a sophisticated analog front-end architecture, resulting in an accurate ECG signal detection and an improved common-mode and isolation-mode rejection.