User and Service Manual XLTEK EEG32U Amplifier
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Theory of Operation:
Introduction
This section describes the theory of operation of the 32 channel EEG headbox. The initial discussion is
primarily signal flow oriented. Detailed board level theory is provided later in this section.
System Overview
Features of the EEG32U System
The EEG32U headbox performs these basic functions of a digital EEG front end:
• Allows connecting patient electrodes.
• Amplifies and digitizes the electrode signals.
• Transmits the digitized waveforms to a NeuroWorks computer.
• Allows selection of reference signal.
• Provides internally generated test signals (sine and square) for user assessment of equipment
performance.
Components of the Communications Link
• Digitized waveforms are transmitted to the computer using USB (universal serial bus) connection.
• Commands and replies are communicated using same USB (universal serial bus) connection.
Power Sources to the Headbox
• Power to EEG32U is supplied by a USB bus.
Circuit Board Assemblies inside the Headbox
A. Analog Board
• Handles amplification and DC removal (DC removal is similar to a low frequency filter) for 32
channels.
• Amplifiers are designed to handle signals far in excess of even abnormally high EEG, while also
providing exceptional sensitivity and resolution.
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