Several Issues In EEG Detection

With the rapid development of science and technology, people tend to be more curious about the abundant information stored in human brain. Analysis of the information provides insight into the function of human brain and could be used to discover abnormal pathological changes in brain. Therefore, it is vitally fundamental to research on the EEG signal detection.This paper is composed of three sections as follows. The first part is a design of 4-Channel EGG amplifier. This part is intended to amplify and filter the detected EGG signals to obtain analyzable EEG wave form. The second part is a design of lead-off detection.When measuring EEG signals, detachment of electrode will result in failure to obtain correct EEG wave form. This detecting function is achieved by a peripheral circuit design and indicated by a light-emitting diode. This part is designed to guarantee a correct detection. The third part is an experiment on human body’s contact impedance under different frequencies. The experiment reached a rule of human body’s contact impedance variation with frequency by measuring the impedance under different frequencies. This result is a important reference for designing the equipment.