Laboratory of Industrial Electronics, Control and Instrumentation (LEICI), University of La Plata, CC 91, 1900 La Plata, Argentina.
Med Biol Eng Comput. 2011 Sep;49(9):1067-71. doi: 10.1007/s11517-011-0811-6. Epub 2011 Jul 20.
Biopotential measurements are very sensitive to electromagnetic interference (EMI) from power-lines. Interference conditions are mainly imposed by electric-field coupling, whose effects can be described by coupling capacitances. The main of them are the patient-to-ground and the patient-to-power-line capacitances, usually denoted as C(B) and C(P), respectively. A technique to estimate these elements and experimental data obtained in different environmental conditions are presented. It was found that C(B) ranges from hundreds of pF to nF, and C(P) from hundredths of pF to few pF. The presented technique also lets it know the small amplifier-to-ground and amplifier-to-power-line capacitances. The knowledge of all these capacitances allows estimating the EMI conditions that biopotential amplifiers can be subject to, thus, resulting useful data for specifying their design requirements and constraints in real working conditions.
生物电位测量对来自电源线的电磁干扰（EMI）非常敏感。干扰条件主要由电场耦合引起，其影响可以用耦合电容来描述。其中主要的是患者到地和患者到电源线的电容，通常分别表示为 C(B)和 C(P)。本文介绍了一种估计这些元件的技术和在不同环境条件下获得的实验数据。结果发现，C(B)的范围从几百 pF 到 nF，C(P)的范围从百分之一 pF 到几 pF。所提出的技术还可以了解到放大器到地和放大器到电源线的小电容。了解所有这些电容可以估计生物电位放大器可能受到的 EMI 条件，从而为在实际工作条件下指定其设计要求和限制提供有用的数据。
