Design and implementation of a contactless ECG acquisition system

Abstract

The measurement of signals from human body is achieved usually through the use of electrodes in direct contact with skin. Typically, these measurements are performed using Ag/AgCl electrodes with conductive gels or dry contact electrodes in direct contact with skin. In recent years, non-contact electrodes have been considered as an alternative option offer several benefits such as stability over time in long-term monitoring applications, the ability to make the signal monitoring more comfortable for the patient and it does not require the presence of qualified medical staff. The aim of this thesis is to design and implement a contactless sensory system for the detection of ECG signals. The approach is based on a coupling with human body performed by electrodes integrated in a front-end circuit, detects changes of electric charge that are related to cardio muscle activity. The signal from the human body generally characterized by low intensity and narrow bandwidth, and also the electrodes do not perfectly transmit the signal and distort the signals slightly. Therefore, due to the presence of other undesired signals suitable amplifications and analogue filters are required in order to obtaining a clear signal.