A wearable electrocardiogram (ECG) measuring system is designed based upon capacitively coupled biopotential sensing electrodes. The sensing electrodes are made from the standard printed-circuit board. Using a reversely connected diode to provide the required high-value bias resistance, the pickup circuit for biopotential sensing is implemented by a high-input-impedance instrumentation amplifier. Two different configurations of the ECG measuring system are constructed and experimentally tested. One is a floating ground configuration in which only two sensing electrodes are used for ECG signal acquisition. Another is the passive ground configuration in which an additional grounding electrode is employed as the reference for common-mode noise suppression. The ECG signal can be obtained through thin clothes for both cases but performs lower signal-to-noise ratio. In order to improve the quality of the obtained signal, an algorithm based on a singular spectrum analysis is designed for noise reduction. A matching template is introduced to pick out the critical principal components automatically. Experimental results show that, with the aid of the proposed algorithm, satisfied ECG and respiration signals can be effectively obtained outside cotton-fiber clothing.

中文翻译：

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电容耦合心电图测量系统与奇异谱分析降噪

基于电容耦合生物电势传感电极设计了一种可穿戴心电图 (ECG) 测量系统。感应电极由标准印刷电路板制成。使用反向连接的二极管来提供所需的高值偏置电阻，用于生物电位传感的拾音电路由高输入阻抗仪表放大器实现。ECG 测量系统的两种不同配置被构建和实验测试。一种是浮地配置，其中只有两个传感电极用于 ECG 信号采集。另一种是无源接地配置，其中使用额外的接地电极作为共模噪声抑制的参考。两种情况下都可以通过薄衣服获得心电图信号，但信噪比较低。为了提高获得信号的质量，设计了一种基于奇异谱分析的降噪算法。引入匹配模板以自动挑选关键主成分。实验结果表明，借助所提出的算法，可以在棉纤维衣物外有效获取满意的心电图和呼吸信号。