Study And Design On Miniaturized Acquisition And Stimulation System For EEG

Electroencephalogram(EEG)plays an important role in the diagnosis of brain diseases,mental state monitoring,brain computer interface research and so on.Traditional EEG signal acquisition equipment is confronted with more and more difficulties and challenges in terms of volume and frequency range of the signal.At the same time,the method of electric stimulation which is generally applied to the diagnosis and treatment of diseases such as epilepsy,pseudomyopia and study of neural feedback,but it is inconvenient and complex to use the timing synchronization circuit to coordinate the electrical stimulation device and acquisition equipment to complete the acquisition of feedback signal caused by stimulation.To solve these problems,a miniaturized EEG signal acquisition and stimulation system is designed in this paper,which is characterized by wireless,mobile and portable.It can be widely used in biomedical fields and provide key acquisition nodes for future wisdom medical field.The main contents of this system include:1.An asynchronous "ping-pong" data throughput mechanism is implemented.Triple buffering is a scheme that front-end acquisition equipment can connect to back-end data processing equipment without the timing synchronization circuit which can send the last acquired data and store the newly acquired data at the same time which improve the compatibility of terminal equipment and acquisition equipment.The system can complete the real-time monitoring of EEG in the asynchronous mechanism.2.A stimulus and acquisition coordination mechanism is designed to solve the problem that additional equipment and manual operation is needed to do stimulation.As long as presetting the frequency of the stimulus signal,waveform and collaboration time point,the electrical stimulation can accurately cooperate with the acquisition channel to complete the effective stimulation and targeted monitoring of the feedback signal.3.Software notch which have a good performance on out-of-band suppression rate is designed to replace traditional hardware filtering.At the same time,the system achieves smaller volume and lower cost.The hardware solution and verification of the proposed system solution are carried out in this paper.The results show that the system test data and signal source in line with the better transmission rate of 6Mbps,reliable transmission distance of 10 m,to achieve real-time transmission;power consumption 500 mW,terminal mechanical size 65 * 40 * 42 mm,to meet the miniaturization requirements;Up to 6Msps,which can simultaneously sample 8 channels,the effective monitoring frequency range 1 ~ 1kHz,the design reached the intended target.