Common-mode noise cancellation circuit for wearable ECG

Abstract

Wearable electrocardiogram (ECG) is attracting much attention for monitoring heart diseases in healthcare and medical applications. However, an imbalance usually exists between the contact resistances of sensing electrodes, so that a common mode noise caused by external electromagnetic field can be converted into the ECG detection circuit as a differential mode interference voltage. In this study, after explaining the mechanism of how the common mode noise is converted to a differential mode interference voltage, the authors propose a circuit with cadmium sulphide photo-resistors for cancelling the imbalance between the contact resistances and confirm its validity by simulation experiment. As a result, the authors found that the interference voltage generated at the wearable ECG can be effectively reduced to a sufficient small level.

Keywords

• electrocardiography
• medical signal processing
• signal denoising
• diseases
• patient monitoring
• biomedical electrodes
• photoresistors
• cadmium compounds
• biomedical electronics
• common-mode noise cancellation
• wearable ECG
• electrocardiogram
• heart disease monitoring
• healthcare
• medical applications
• contact resistances
• sensing electrodes
• external electromagnetic field
• ECG detection circuit
• differential mode interference voltage
• cadmium sulphide photoresistors
• CdS