基于高输入阻抗放大器的EEG传感器设计

EEG sensor design based on amplifier of high input impedance

脑电(头皮脑电)图(EEG)是医疗上重要的诊断信息,目前非接触式干电极在采集EEG信号时具有使用简单、不易受环境约束的优点,具有着广阔的应用前景,已经成为全世界的热门研究课题。由于人体皮肤具有很高的阻抗,故要求非接触式干电极具有高输入阻抗。为了提高输入阻抗,采用深度电压串联负反馈来实现超高输入阻抗放大电路,并给出电路的设计和分析。深度电压串联负反馈的前置放大器能提供高达2.6×1011Ω的输入阻抗,有助于非接触式干电极进行信号的采集。

Electroencephalogram（EEG） is an important diagnostic medical information, currently non-contact dry electrode has advantages of simple to use and less susceptible to environmental constraints in acquisition of EEG signals, thus it has broad application prospects, and has become a hot research topic worldwide. Because human skin has high impedance, thus require non-contact dry electrode has high input impedance. In order to increase input impedance, use depth of series of negative feedback voltage to achieve amplifier circuit of ultra-high input impedance, and give design and analysis of circuit. Depth voltage series negative feedback preamplifier can provide up 2.6 × 1011Ω input impedance, which helps non-contact dry electrodes for signal acquisition.