This article presents an analysis of active electrode design for capacitively coupled measurement of bioelectrical signals. It deals with constructing an active electrode using a guard layer to decrease its input's parasitic capacitance. Three dielectric materials (cotton, polyester, wool) were examined under different pressure (1.23 kPa, 3.07 kPa) of the active electrodes. The Common Mode Rejection Ratio (CMRR) analysis of the system using guarded and unguarded electrodes is also investigated. The results show that the guard layer increases the active electrode's gain in the whole measured frequency range for all insulation materials and pressures. An unguarded active electrode reaches a gain of −7.45 dB while using cotton as dielectric material under the pressure of 1.23 kPa compared to the guarded active electrode, which reaches the gain value of −0.47 dB at the same conditions. The measurements of the CMRR prove that the guard layer increases the system CMRR.

本文介绍了用于电容耦合测量生物电信号的有源电极设计。它涉及使用保护层构造有源电极以减小其输入的寄生电容。在活性电极的不同压力（1.23 kPa，3.07 kPa）下检查了三种介电材料（棉，聚酯，羊毛）。还研究了使用保护电极和未保护电极的系统的共模抑制比（CMRR）分析。结果表明，对于所有绝缘材料和压力，保护层均可在整个测量频率范围内增加有源电极的增益。与保护性有源电极相比，在1.23 kPa压力下使用棉作为电介质材料时，无保护性有源电极的增益为−7.45 dB，在相同条件下达到-0.47 dB的增益值。CMRR的测量证明保护层可增加系统的CMRR。