Objective To study the application of wearable small size capacitively-coupled electrode in manned spaceflight. Methods To deal with the influence of the size reduction of the electrode on the amplitude and the noise of the signals,the dynamic drive shield electrode structure,the impedance conversion amplifier with excellent noise performance were used in the system design and the wavelet threshold filtering algorithm was used to denoise. Results As compared with the 4 cm diameter electrode,the amplitude of the signals detected by the 2 cm diameter capacitively-coupled electrode was reduced,but the P wave,the QRS wave and the T wave of the ECG signals were completely detected. Small size electrode had certain advantages in reducing the interface noise and wavelet threshold filtering eliminated noise effectively. Conclusion The ECG detection system using small size capacitively-coupled electrode in this paper realized the non-contact detection of ECG signals across the clothes. The signal waveforms were clear and complete,which could meet the requirements of space medical monitoring.
