Active capacitive ECG system with all-digital "driven right leg" common mode suppression

Abstract

A digital system for capacitive ECG measurement is proposed, including a digital driven right leg loop, which compared to current analog systems, can provide significantly greater robustness for the placement of electrodes in real-world scenarios such as inside a vehicle, as well as greater flexibility in algorithmically defining the optimal ECG electrode positions in an array post-acquisition. The system is stable with high DRL gains and successfully rejects common mode interference, such as motion artefacts from nearby movements, by up to 60dB.