Dry Electrode Based Low-power ECG Acquisition System with Adaptive Motion Artifacts Cancellation

Abstract

Wearable wireless smart ECG sensing system has been a promising technology given that medical health monitoring is growing widely and ubiquitously. An effective ECG monitoring system can diagnose and detect any abnormalities from the gleaned data. This paper proposes a low-power ECG acquisition system using wearable nodes that cancels the motion artifacts caused by physical movements such as walking and running. The adaptive motion artifacts cancellation technique can be utilized to achieve reliable ECG signals. 12 wt% multi-walled carbon nanotube/polydimethylsiloxane (MWCNT/PDMS) composite based dry electrodes along with an on-chip amplifier are used to record the ECG without creating patient discomfort. The ECG sensing system along with the artifacts cancellation features is designed in standard 180 nm CMOS process. A two-stage ECG amplifier achieves a gain of 38 dB occupying 0.1 Hz - 1 kHz frequency bandwidth. An 8-bit SAR-ADC and an on-off keying modulated transmitter are also designed in the MICS band followed by the least mean square (LMS)-adaptive filter. The whole system shows to acquire ECG data wirelessly with efficient power performance and a high signal-to-noise ratio of 42 dB of the filtered signal, which is an 8% improvement compared to the raw ECG data.