用于双电极生物电位放大器的直接干扰消除

Direct interference canceling for two-electrode biopotential amplifier.

作者信息

Hwang In-Duk, Webster John G

机构信息

University of Wisconsin, Madison, WI 53706, USA.

出版信息

IEEE Trans Biomed Eng. 2008 Nov;55(11):2620-7. doi: 10.1109/TBME.2008.923108.

DOI:10.1109/TBME.2008.923108

PMID:18990632

Abstract

A two-electrode biopotential amplifier, though simpler than a three-electrode amplifier, has problems rejecting 60 Hz power-line interference due to the imbalance of electrode-skin impedance. A direct interference canceling (DIC) scheme to reject 60 Hz interference for a two-electrode biopotential amplifier is proposed. The DIC scheme cancels differential-mode interference directly by adding to the interference to be canceled a feedback signal that has the same magnitude and frequency as the interference, but that has phase shifted 180 degrees. When the DIC is started by closing a switch, transient interference appears, which decreases within several seconds. In steady state, the DIC amplifier rejects a very narrow bandwidth (BW) centered at the interference frequency. The proposed circuit was implemented and the DIC operation yielded 54 dB interference canceling with 0.6 Hz rejection BW.

摘要

两电极生物电位放大器虽然比三电极放大器更简单，但由于电极-皮肤阻抗不平衡，在抑制60Hz电源线干扰方面存在问题。本文提出了一种用于两电极生物电位放大器抑制60Hz干扰的直接干扰消除（DIC）方案。该DIC方案通过向待消除的干扰添加一个幅度和频率与干扰相同但相位偏移180度的反馈信号，直接消除差模干扰。当通过闭合开关启动DIC时，会出现瞬态干扰，该干扰会在几秒钟内减小。在稳态下，DIC放大器抑制以干扰频率为中心的非常窄的带宽（BW）。所提出的电路已实现，DIC操作产生了54dB的干扰消除效果，抑制带宽为0.6Hz。