基于 STM32 的脑电信号采集系统设计

脑电信号包含大量的脑功能状态信息，已被广泛应用于脑神经疾病诊断、脑机接口、睡眠分期、麻醉深度监测等领域。脑电信号是幅度为微伏级的生物电信号，频率不超过 150 Hz，极易受到眼电、心电等信号干扰，因此，有效提取脑电信号是分析脑电信号的前提。文章设计了基于 STM32 的脑电信号采集系统，实现脑电信号的有效采集。通过贴在前额的三导联生物电极，将脑电信号感应至预处理电路，在前端模拟电路中对信号进行多级放大，并设计了无源滤波网络及多个有源滤波器对信号进行滤波和调理，同时加入电平抬升电路、电极连接状态检测电路。利用 12 位模数转换器将脑电信号转换为数字信号，并通过蓝牙模块传至上位机，实现脑电信号的有效提取与传输，为下一步处理分析提供基础。通过对比采集到的脑电信号和国外同类产品的输出，验证了该脑电采集系统的有效性。

Design of Electroencephalogram Acquisition System Based on STM32

Electroencephalogram(EEG) contains a large amount of brain function state information, and has been widely applied in many fields, such as cranial nerve disease diagnosis, brain-computer interface, and sleep stage and anesthetic depth monitoring. EEG is a weak bio-electric signal, whose amplitude is just microvolt and frequency is lower than 150 Hz. Since EEG is easily interfered by signals, like electro-oculogram and electrocardiogram, effective extraction of EEG is key to EEG analysis. An EEG acquisition system based on STM32 was designed to realize effective acquisition of EEG. In this system, EEG signals were sensed by three lead biological electrodes on the forehead, then amplified through multistage amplification in the front analog circuit and filtered by passive filter or active filters. Meanwhile, electrical level rising circuit and electrode connection state detection circuit were also added in. After that, EEG signals were converted to digital value by 12 bit analog-to-digital converter, and then transferred to upper computer via bluetooth module to realize effective extraction and transmission, providing the basis for further processing and analysis. The effectiveness of this EEG acquisition system was verified by comparing output with other similar products.