无线脑电采集中事件时点精密同步记录系统的设计  

Design of Precise Synchronous Recording System for Wireless EEG Acquisition Events

作　　者：刘邈 郭佳明 LIU Miao;GUO Jiaming(Academy of Medical Engineering and Translational Medicine,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学医学工程与转化医学研究院,天津300072

出　　处：《传感技术学报》2021年第10期1401-1405,共5页Chinese Journal of Sensors and Actuators

摘　　要：事件相关诱发电位是一种大脑因外界刺激施加而产生的脑电诱发电位。该电位与刺激之间存在严格的锁时关系,在记录脑电数据的同时还需要精准的记录下刺激发生的时点。目前的无线脑电采集系统中,事件传输过程的延时和延时抖动问题难以解决,导致系统事件同步记录的时间精度无法得到保证,阻碍了相关临床研究和脑机接口工程实现的效果。本文提出了一种基于低成本通用微处理器的方案:先将刺激事件通道从脑电数据采集通道中独立出来以不同信道传输并设计底层低延时的通信协议,再通过采集器软硬件联合保障系统固定延时,最终以无线接收端时钟为基准,通过延时回溯标记事件对应时点以获得高精度事件时点同步。软硬件在环测试表明,该方案能够达到±10μs的事件同步精度,满足科研级无线脑电采集的事件同步精度要求。Event-related evoked potential(ERP)is a kind of EEG evoked potential induced by external stimulations.There is a time-locked relationship between the potential and the stimulus,so it is necessary to accurately record the time of the stimulus while recording the EEG data.However,the synchronous recording of events in the wireless EEG acquisition system is hard to be accurately recorded due to the transmission delay and delay jitter,which hinders the effect of relevant clinical research and brain-computer interface engineering.In this paper,a scheme based on low-cost general-purpose microprocessor is proposed:firstly,the stimulation events are transmitted in a different channel,separated from the EEG data acquisition channels and an underlying low-delay communication protocol is designed.Then,with hardware and software components working together,the system fixed delay is guaranteed.Finally,based on the wireless receiver clock,the high-precision event time-point synchronization is obtained by marking the corresponding time point of the event by delay backtracking.The hardware and software-in-the-loop test shows that this scheme can achieve the event synchronization accuracy of±10μs,which meets the event synchronization accuracy requirements of scientific research-level wireless EEG acquisition.

关 键 词：事件相关诱发电位 无线时间同步 PWM 射频模块 

分 类 号：TP212.3[自动化与计算机技术—检测技术与自动化装置]