高共模抑制比的肌电传感器的电路设计  

Circuit design of electromyographic sensor with high common mode rejection ratio

作　　者：杨成英 YANG Chengying(School of Materials Science and Engineering,Guangdong Ocean University,Yangjiang 529500,Guangdong Province,China)

机构地区：[1]广东海洋大学材料科学与工程学院,广东阳江529500

出　　处：《电子元件与材料》2025年第1期95-102,共8页Electronic Components And Materials

摘　　要：肌电图(EMG)被公认是诊断和鉴别神经肌肉疾病必备的客观检查手段。然而,传统肌电传感器电路存在共模抑制比(CMRR)低、滤波不完整的问题,导致肌电图波动大、精度低。基于具有低失调电压、低增益漂移特性的ADI芯片AD8221放大器,以及具备低输入偏置电流、低输入失调电流以及高转换率的运算放大器TL084,设计了一款高精度的肌电图传感器采集电路。该电路利用运算放大器的特点,将微分电路和绝对值电路有效融合,实现低频(直流)滤波及全波整流功能,同时结合积分电路和低通滤波器的特征,能够滤除高频干扰信号,充分保证传感器高共模抑制比的性能。测试结果表明,电路输出的EMG信号的波形幅度示值误差小于±5%,信号幅度偏差在+2.5%~-15%,共模抑制比高达130 dB,非常适用于高精度的肌电传感器。Electromyography(EMG)is widely regarded as an essential objective diagnostic tool for neuromuscular diseases.However,the common mode rejection ratio(CMRR)is often low for the EMG sensor circuits,and incomplete filtered signals could lead to large fluctuations and low accuracy for the EMG sensors.A high-precision acquisition circuit for the EMG sensors was designed using the ADI chip AD8221 amplifier with low offset voltage and low gain drift,and using the operational amplifier TL084 with low input bias current,low input offset current,and high conversion rate.This circuit utilized the operational amplifier to effectively integrate the differential circuit and the absolute value circuit,which could achieve low-frequency(DC)filtering and full wave rectification functions.Meanwhile,the integral circuit and low-pass filter worked synergically to filter out the high-frequency interference signals,which fully ensured the CMRR for the sensor.The test results show that the waveform amplitude indication error is less than±5%for the EMG output signal from the circuit with signal amplitude deviations between+2.5%and-15%,and the CMRR up to 130 dB.It is very suitable for high-precision electromyographic sensors.

关 键 词：肌电图 传感器 运放 电路 共模抑制比 

分 类 号：TN709[电子电信—电路与系统] TP212[自动化与计算机技术—检测技术与自动化装置]