Design of Portable Multi-Channel EEG Signal Acquisition System

A portable multi-channel electroencephalography (EEG) signal acquisition system operated by battery is designed in this paper. EEG is a recording of the electrical activity of the brain from the scalp and the recorded waveforms provide insights into the dynamic aspects of brain activity. The amplifier with a bandwidth of 0.8-35 Hz is designed by use of integrated circuits such as the low-power instrumentation amplifier AD623, low-power, high gain operational amplifiers TLC27L4, etc. The amplified EEG signals are digitized by an A/D (analog to digital) converter built-in MSP 430 MCU (micro-controller unit). The digitized signals are transmitted to a PC by a wired serial port or stored in the SD (secure digital) memory card. Experimental results show that the system could implement the acquisition and storage of the EEG signals efficiently. This system would be of benefit to all involved in the use of EEG for clinical diagnosis and monitoring, or even BCI (brain computer interface).