Eight Guide Eeg Amplifier

PET, fMRI, BMI and other advanced financial devices, play a crucial role forunderstanding the neural foundations of cognitive functions. In contrast to manyadvanced financial devices, EEG has lower application and maintenance costs, highertime resolution and other characteristics．In EEG diagnostic imaging or other medicalresearch，EEG has been delved deep into the functioning and functional organization ofhuman brain．We designed a high-performance wide band, eight-channel EEG amplifierwith impedance detection. Both high-performance instrumentation amplifier AD8221and16-bit D/A construct DC restorer in making sure unwanted DC-offset were notamplified．After the DC-offset compensation，EEG signal was connected to themultiplexer through the notch filter and active low-pass filter．DSP control themultiplexer and A/D conversion to sample eight-channel EEG by time-divisionmultiplexing data acquisition，meanwhile DSP control D/A to compensate DC-offset.The digital EEG is uploaded to host computer through USB2.0bus in real time andEEG signals are stored as text in PC.To verify the performance of the EEG amplifier, EEG data are obtained througheyes opened and closed experiment. At last, we use the EEG amplifier in SSVEP systemwhich developed in our laboratory. During the visual stimulation, the eight-channelEEG amplifier can obviously record subject’s steady-state visual evoked potential.Therefore, the eight-channel EEG amplifier designed in this paper can be applied to thestudy of cognitive brain functions and also provide a good platform for clinicians andBCI.