基于STM32的脑电信号采集与处理系统

发布时间：2018-11-17 09:54

【摘要】：脑机接口技术是在大脑与外部设备之间建立直接交流关系的技术，是现代生物医学工程领域的热点课题之一。该技术的主要目标是帮助身体某些器官或组织有缺陷的人，实现大脑对外部设备的控制和操纵，从而弥补自身行动的不足。该技术的核心是脑电信号的采集与处理。本文提出了一种脑电信号无线采集与处理系统，利用该系统可以实现对老鼠脑电信号的采集与后续处理。该系统在结构上分为发送和接收两部分。由于本课题的构想是要实现对自由活动老鼠的脑电信号采集与处理，所以要求背在老鼠身上的发送电路板必需要轻便，而且要有无线发射功能。这样就必然要求接收电路板要具有无线接收功能和与电脑上位机通信的功能。本文的绪论部分首先介绍了脑机接口技术的研究意义及其国内外研究现状，然后介绍了本课题的来源及主要工作内容。本文的第二章对脑电信号的特点和各种脑机接口技术做了比较细致的介绍。通过对脑电信号特点的了解，可以确定我们想要设计的脑电信号采集与处理系统所要满足的一些特性与功能，给我们提供了理论上的依据与研究方向。本文的第三部分介绍了系统的总体框架，比较细致的介绍了系统每一部分的组成。对于发送与接收部分所用到的微处理器、A/D转换、串口转USB以及电源芯片等都做了一一介绍，重点介绍了它们的性能和在本设计中采用它们的原因。微处理器我们采用的是ST公司的带有射频模块的芯片stm32w108，A/D转换芯片采用的AD7993。本论文的重点在第四部分，即前端模拟电路的设计部分。该部分详细介绍了前端模拟电路的结构与组成原理。按照在电路结构中由前到后的顺序，逐级介绍了每一级的电路原理图和所要实现的功能，对每一级电路中用到的运算放大器和滤波器等芯片的性能参数也做了一定介绍。第一级放大对模拟电路的性能影响很大，所以在这一级我们采用的是仪表放大器INA118，保证第一级的共模抑制比足够高。前端模拟电路在整个系统中占有非常重要的位置，由于它处于系统的最前端，负责采集最原始的模拟信号，所以对它的性能要求很高，在这一部分我们花费了最大的精力来研究。在论文的最后，我们介绍了相关仿真与一部分实际测试结果，并介绍了电路板的制作情况。然后对整个系统的总体设计做了总结与展望，，对设计中存在的相关问题和未完成的工作做了一定介绍与分析。
[Abstract]:Brain-computer interface (BCI) is a direct communication technology between the brain and external equipment, which is one of the hot topics in the field of modern biomedical engineering. The main goal of the technology is to help people with defects in certain organs or tissues of the body to control and manipulate external equipment to make up for their lack of action. The core of this technology is the acquisition and processing of EEG signals. In this paper, a radio acquisition and processing system for EEG signals is proposed, which can be used to collect and follow up the EEG signals of mice. The structure of the system is divided into two parts: transmitting and receiving. Because the idea of this subject is to collect and process EEG signals from free-moving mice, it is necessary to have portable transmission circuit board and wireless transmitting function. In this way, the receiving circuit board must have wireless receiving function and the function of communicating with PC. The introduction of this paper first introduces the research significance of BCI technology and its research status at home and abroad, and then introduces the source and main work content of this topic. In the second chapter, the characteristics of EEG and various brain-computer interface techniques are introduced in detail. Through the understanding of the characteristics of EEG signal, we can determine some characteristics and functions of the EEG acquisition and processing system that we want to design, and provide us with theoretical basis and research direction. The third part of this paper introduces the overall framework of the system, and details the composition of each part of the system. The microprocessors used in the sending and receiving parts, such as A / D conversion, serial port to USB and power chip, are introduced one by one. Their performance and the reasons for their adoption in this design are emphatically introduced. The microprocessor we use is ST's chip with RF module, stm32w108,A/D conversion chip and AD7993.. This paper focuses on the fourth part, that is, the design of the front-end analog circuit. In this part, the structure and principle of the front-end analog circuit are introduced in detail. According to the order from front to back in the circuit structure, the schematic diagram of each stage and the functions to be realized are introduced step by step, and the performance parameters of chips such as operational amplifiers and filters used in each stage circuit are also introduced. The first stage amplifier has a great influence on the performance of analog circuit, so at this stage we use the instrument amplifier INA118, to ensure the first stage of the common mode rejection ratio is high enough. The front-end analog circuit occupies a very important position in the whole system. Because it is in the front end of the system, it is responsible for collecting the most original analog signal, so the performance of the analog circuit is very high. In this part we have spent the greatest effort to study. At the end of the paper, we introduce the simulation and some actual test results, and the fabrication of the circuit board. Then the overall design of the whole system is summarized and prospected, and the related problems and unfinished work in the design are introduced and analyzed.
【学位授予单位】：山东师范大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R318

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