Circuit Design Of 64-Channels EEG Acquisition System

The research of brain science has been a hotspot on the field of human health for years.EEG signal,its unique advantages of non-destructive and non-invasive,is widely used in brain disease and brain-computer interface research.The brain cognitive research generally use 32,64 or 128 channels of the EEG acquisition system,the more electrodes used the richer EEG space information can be acquired.EEG acquisition system is precision electronic equipment to amplify the micro-volt-level EEG signal,which also susceptible to environmental electromagnetic radiation interference.Nowadays,commercial EEG acquisition system mainly adopts AC coupling mode.A few high performance products with DC or AC coupling mode used in scientific research,but the tow modes can't be used at the same time.In this paper,we propose a wideband and high gain DC-coupled EEG acquisition system to compensate the shortages of normal DC coupling mode.Circuit design can be divided into two main parts,hardware circuit design and the physical drive software design.The core competitive of the circuit design is analog front-end circuit and data path of analog signal acquisition board.High-performance analog signal acquisition board significantly improves SNR of EEG,it is important for user experience with the impedance detect function.The EEG acquisition system with up to 10 kHz sampling rate,making the EEG gets high resolution in time domain.Analog front-end circuit,with 100 dB CMRR,can effectively inhibit the common mode interference signal,while the notch filter circuit can effectively filter 50 Hz power line interference.The dynamic DC correction technology makes the polarization voltage drift of the electrodes be greatly improved.Through the MOVEP,P300,SSVEP and many other EEG experiments to verify the performance of EEG acquisition system.The results show that the 64-channels EEG acquisition system achieve the requirements of acquiring spontaneous EEG and evoked EEG,and suitable for brain science research.