电极电位与放大器的前级设计

Electrode Potential and Design of First Stage Amplifier

在生物电信号的采集放大过程中，电极电位常可引起不易察觉的干扰和信号畸变，影响正常波形的判断识别。主要影响机制为：放大器前级部分阻塞、“高频斩波”式干扰、分布电容变化干扰及电极引线漏电噪声。作者提出电极电位抵消和前级高频预滤波电路，并结合前级隔离、驱动屏蔽技术应用于放大器的前级设计，可大大提高放大器对电极电位的耐受能力，基本消除电极电位的影响。

During collecting and amplifying bio-electrical signals,potential of electrode often causes inperceivable interference and signal distortion, which could lead to misjudge the normal waveform. The main mechanism is as follows :partial blockage of the first stage amplifier,'high frequency wave chopping' interference,interference of the change of scattering capacity and noise from leakage current of electrode leads. The authors proposed a circuit of correcting electrode potential and high frequency pre-filter,combined with the application of isolation first stage of ampilfier and shelter drive technic on the design of first stage ampilfier,resulted in the increasing the tolerance of amplifier and eliminating the most influence of electrode potential.