Noise-Reducing Fabric Electrode for ECG Measurement

Figures

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  Figure 1. Relationship between the human body, skin-electrode interfaces, ECG measurement system, and noises. PLI, EMG and EM mean power line interference, electromyogram, and electrode motion, respectively.

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  Figure 2. An overview of the proposed analog filter.

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  Figure 3. The relationship of the impedance between each electrode.

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  Figure 4. The impedance between the skin and the electrode.

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  Figure 5. The simulation result changing Rc, Cc, and Ce.

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  Figure 6. The structure of the fabric capacitor. (a) The conventional fabric such as pressure sensor. (b) The proposed fabric.

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  Figure 7. The prototype of the proposed electrode. (a,b) show the top view and bottom view, respectively. The fabric capacitor consists of the vertical and the horizontal conductive fabric. The area connecting with the skin is 2×2cm2. To prevent skin touching the fabric capacitor, we used a non-conductive fabric in (b). The total thickness of the fabric electrode including that of a non-conductive fabric was about 1 cm.

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  Figure 8. The environment for measuring the capacitance of the electrode.

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  Figure 9. Overview of the ECG measurement system. The system has three inputs from the right arm V−, the left arm V+, and the reference electrode Vref. V− and V+ are our proposed fabric electrodes, and Vref is a non-folded fabric electrode. The ECG signal is sent to laptop via Bluetooth.

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  Figure 10. The circuit for the ECG measurement. The red line indicates the proposed electrode. The circuit consists of the twin-t notch filter, the first order high-pass filter and the amplifiers.

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  Figure 11. The ECG measurement result using the non-folded fabric electrode at rest. (a) The measured signal and the signal filtered by FIR filters. (b) The high-frequency component above 100 Hz in (a). (a,b) are the common in Figure 12, Figure 13 and Figure 14.

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  Figure 12. The ECG measurement result using the proposed fabric electrode at rest.