Design and Simulation of Amplifier of Electroencephalograph

On the basis of existing biological electricity amplifier which is studied,a design of new type and high performance amplifier circuit was proposed which is in agreement with the characteristic of the EEG signal and the circuit has prevented the traditional design from enlarging the miscellaneous simulation of the circuit and straining the wave link.First,the high Common Mode Rejection Ratio(CMRR) was achieved by the use of instrumentation amplifier INA326 with low consumed power;Then,in order to eliminate the strong background noises of EEG signal,50Hz notch filter and low-pass filter have been introduced in this design and realized the amplification and collection of weak EEG signal.Finally,the feasibility of the design is proved according to the simulation of preamplifier and 50Hz notch filter by the use of TINA software.The results indicate that the circuit has a bright applicable future because of its characteristics of high input impedance,high CMRR,low noises,low degree of nonlinear and high anti-interference ability.