Abstract
A very low noise amplifier, capable of recording signals in the nV range, over a very large frequency band (0.1 Hz – 0.4
MHz) was designed and built. The amplifier was conceived as a tool that will be used to record EEG signals and evoked
potentials. The electronic design of the amplifier is based on differential cascodes (JFET - BJT transistors connected in a
common source - common base configuration). The equivalent input noise of the amplifier is 7 nV/ Hz measured at 22
Hz, corresponding to 1 f corner frequency. The amplifier’s signal-to-noise ratio is 125 dB. An EEG signal, was recorded
using the amplifier then filtered and compared to some EEG signals taken from the scientific literature..
Keywords
Instrumentation amplifier, EEG signals, Evoked potentials.
Citation
C. DONOS, A. POPESCU, L. GIURGIU, New designed EEG amplifier – theoretical calculations and experimental recordings, Optoelectronics and Advanced Materials - Rapid Communications, 5, 6, June 2011, pp.613-616 (2011).
Submitted at: June 3, 2011
Accepted at: June 9, 2011