Description and Operation
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1.5. Technology and Operation
Digital EEG system mode of operation is based on the acquisition and input of brain
biopotentials and other physiological signals into PC for the analysis of brain electrical
activity taking into account the influence of the other physiological signals.
The functional circuit of the digital EEG system is shown in Fig. 1.
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Fig. 1. The functional diagram of the digital EEG system.
EEG, ECG, breath and direct current DC1, DC2 biopotentials are amplified, digitized
in turn by means of analog-digital converter (ADC) and multiplexer (MPX) under the
control of the processor PU1, they are transmitted to USB processor through the
optrons of galvanic isolation.
The processor PU1 of amplifier module controls measurement, calibration, impedance
measurement and internal diagnostics modes.
The power supply of the amplifier module is performed through electrically isolated
DC converter (SU1).
The processor PU2 controls audio stimulus level, duration, frequency and polarity. It
controls the stimulus duration of photic stimulator and generates commands to pattern
stimulator via the signal generators G1, G2, G3.
All the processors receive commands and transmit data through USB processor which
forms data packets to transmit them to computer and deciphers data transmitted from
computer to control the modules.
Digital EEG system operates under control of PC (IBM PC type) with the mouse, key-
board, laser or ink jet printer and installed licensed Windows XP/Vista/7/8 operational
system.
Signal processing, displaying and presentation in different modes after mathematical
analysis, storing of the EEG traces on the hard disc, exam report generation and their
printing is done with the use of PC.
