An Analog Front-End for EEG Data Retrieval with High Noise Rejection

Electroencephalography is a technique used to evaluate and record the brain's electrical activity. It is used mostly for medical purposes, to identify various brain disorders like epilepsy, tumors, and others, but recently it has been used for developing more sophisticated sensors in everyday life. In this paper, an analog front-end circuit for electroencephalography acquisition systems with skin electrodes is proposed. Designed with simple components the circuit achieves a high gain of the electroencephalograph signals with high rejection of environmental electro-interference. Measurement results show a common mode rejection at 50 Hz is better than 33 dB and at 100Hz better than 24 dB. The overall sensitivity is ±1 u Vp-p and the output range is about ±200m Vp-p. The circuit is suitable to be used for driving analog to digital converters or other platforms for post-processing of the electroencephalograph signals.