EEG Bio-Amplifier

Abstract

A low-noise bio-potential amplifier, for use with weak bio-signals such as EEG (electroencephalogram), has been developed, specifically for use in Brain-computer Interface systems. This can be used to remove noise and amplify bio-signals to improve signal quality and provide adequate voltage levels for digitisation and signal processing. Using a series of filters and multi-stage amplification, the bio-amplifier band-passes frequency components in the range 1Hz and 35Hz, and provides a gain in the range 8000 to 1000,000. The gain and offset are adjusted automatically, so as to maintain the output in the 0 - 1V range. This bio-amplifier unit is routinely used in our SSVEP-based BCI system and its performance has been in par with a commercially available system.