The development of high precision EEG amplifier for the computerized EEG analysis

A high precision EEG amplifier for computerized EEG analysis is implemented. It is mainly divided into two parts. The preamplifier part consists of calibration signal generator and signal amplifier with a impedance converter, shield driver, body driver, differential amplifier, and isolation amplifier. The main amplifier part includes the 60 Hz notch filter, variable low pass filter, variable high pass filter and variable gain amplifier. The preamplifier is designed to get the low noise, high CMRR, high input impedance, and a good isolation barrier. The parameter setting of main amplifier is fully controlled by computer interface. The SCF filter is incorporated at notch and lowpass filter to get the wide range of cut off frequency. The anti-aliasing condition of linear phase and sharp transition for later computer analysis is also satisfied