Abstract In order to suppress DC voltage of the raw EEG, and improve commonmode rejection ratio (CMRR) and broaden bandwidth of the EEG, a full spectrum EEG acquisition system that can dynamically eliminating DC voltage was designed in this paper. DC voltage was acquired by microprocessor, and then the DC voltage was translated into analog signal by digital-to-analogue conversion (DAC) and fed back to the dynamical eliminating system of DC voltage. The DC voltage was handled by the system, and then DC components were exported to REF of the instrumentation amplifier, and the DC voltage can be eliminated. Test results showed that not only the DC voltage of the EEG acquisition system could suppress dynamically, but also CMRR could be increased up to more than 120 dB, and the full spectrum EEG (DC-1000Hz) could be acquired. Therefore the EEG acquisition system could acquire more precise EEG signals and be used for research in cognitive science and medical diagnosis to promote development of brain science. Besides that, because of the simple circuit structure, it could be integrated into flexible printed circuit, and made into wearable medical monitoring device, which can help people monitor their physiological status.
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