Common mode noise cancellation for electrically non-contact ECG measurement system on a chair.

Electrically non-contact ECG measurement system on a chair can be applied to a number of various fields for continuous health monitoring in daily life. However, the body is floated electrically for this system due to the capacitive electrodes and the floated body is very sensitive to the external noises or motion artifacts which affect the measurement system as the common mode noise. In this paper, the Driven-Seat-Ground circuit similar to the Driven-Right-Leg circuit is proposed to reduce the common mode noise. The analysis of this equivalent circuit is performed and the output signal waveforms are compared between with Driven-Seat-Ground and with capacitive ground. As the results, the Driven-Seat-Ground circuit improves significantly the properties of the fully capacitive ECG measurement system as the negative feedback.

A Preliminary Study for Unconstrained Pulse Arrival Time (PAT) Measurement on a Chair.

A method of measuring the pulse arrival time (PAT) non-consciously on a chair is proposed. In this method, the electrically non-contact ECG measurement system and the air cushion with balancing tubes are used. In this paper, the correlation between the typical PAT and the unconstrained PATs (A-PATs) are compared. The typical PAT is measured as the difference of R-peak of ECG and the steepest descent point of the PPG in toe. The three different A-PATs were measured from the pressure pulse of the air cushion (APP). The correlation between the typical PAT and the A-PAT from the steepest descent point of the APP was the highest (R=0.9663).