Design and implementation of EEG Measuring System

*, **
* Lecturer, Department of Electronics and Communications Engineering.
** Department of Medical Engineering, Nahrain University.
Periodicity:June - August'2012
DOI : https://doi.org/10.26634/jele.2.4.1902

Abstract

Electroencephalograph (EEG) is a technique commonly used in medical and research fields to record the electrical activities of the brain. The EEG signals are recorded from the surface of the scalp metallic electrodes. The EEG signals are within the range of (0.5-50µV), the raw signals are originated from different areas of the brain. The locations of these electrodes on the scalp are specified according to the 10-20 international system. Measuring the EEG signals is usually difficult due to small signal magnitude of the EEG signals and large DC offset voltage incorporated with the measuring process. The DC-offset in EEG signal is a result of many factors, like electrode-skin interface, amplifier input bias current mismatch, input impedance, offset voltage, and voltage drift with temperature and aging. The signal is amplified in two stages and digitized using a 24-bit analog to digital convertor (ADC). The DC-offset was treated using auto-zeroing technique, along with the use of high precision electronic components. The theoretical design was first simulated using TINA-TI software, then the PCB's were designed using Eagle software, and implemented experimentally. EEG signals were acquired and recorded for different people and it seems satisfactory for the diagnosis by doctors.

Keywords

Electroencephalography, Ag/AgCl electrodes, DC-offset, Auto-zeroing using integrator, 24-bit ADC.

How to Cite this Article?

Safaa S. Mahdi and Mahir R. Alhajjaj (2012). Design and Implementation of EEG Measuring System. i-manager’s Journal on Electronics Engineering, 2(4), 21-26. https://doi.org/10.26634/jele.2.4.1902

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