| The21stcentury is the era of biologicalsciences and brain science. As one of the typicalbiological signals, The electroencephalograph (EEG) contains a large number of physiologicaland pathological information, which are becoming been studied more widely in today’smedical and other scientific fields. The EEG acquisition is generally through a dedicatedelectrode, the weak EEG signal first passes through the amplification, isolation, filtering, andthen we can do recording and processing analysis to it.This paper analyzes the research situation and development trend of the EEG, and thenintroduced a set of EEG acquisition system based on FPGA. The system has the features ofhigh integration density, good flexibility and practicability. It is in line with the developmenttrendof modern EEG, and meet the new requirements of modern EEG.The effective frequency range of the EEG is generally0.5-30Hz, the amplitude is in therange of between10uV-100uV, it is prone to influencing from noise such as the powerfrequency noise, EMG noise and so on, and lost in the noise signal. This system designs theanalog filter to suppress interferences, including the35Hz low-pass filter,the0.3Hz high-passfilter and the50Hz frequency notch filter, at the same time,we designs the FIR digital filterbased on the FPGA to filter out the restrain noise and get the pure EEG. The system used theFPGA as the core processor, the EEG signal after amplification, filtering, isolation, and thenenter into the AD converter, in order to be able to capture more details of the EEG signal,the system uses the AD7920AD converter and set the sampling frequency of each guide to400Hz, the EEG signal after digital filter enter into the FIFO buffer, and then are sent to thePC through USB interface in the control of the FPGA. The PC application receive the EEGsignal data via the USB port and draw the brain electrical waveform diagram.Plus,the systemis equipped with the LCD interface,we can observe brain wave graph through it. |
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