A multichannel EEG acquisition scheme based on single ended amplifiers and digital DRL.

Area of Science:

• Biomedical Engineering
• Signal Processing
• Neuroscience Instrumentation

Background:

• Single-ended (SE) amplifiers offer a simplified design for biopotential front-ends, suitable for compact electroencephalography (EEG) systems.
• However, SE amplifiers suffer from poor common-mode rejection ratios (CMRRs) due to gain mismatching between channels, limiting signal quality.
• Existing methods struggle to effectively mitigate power line interference in multichannel EEG acquisition.

Purpose of the Study:

• To propose and validate a novel scheme for multichannel EEG acquisition systems using SE amplifiers.
• To address the limitation of poor CMRR in SE amplifier-based front-ends.
• To introduce a digital driven right leg (DDRL) circuit for enhanced common-mode reduction.

Main Methods:

• Implementation of a multichannel EEG acquisition system utilizing SE amplifiers.
• Integration of a novel digital driven right leg (DDRL) circuit with the SE amplifier front-end.
• Construction and testing of a functional prototype to evaluate performance.

Main Results:

• The proposed system effectively overcomes the poor CMRR of the SE amplifier front-end.
• Achieved high common-mode reduction at power line frequency, reaching up to 80 dB.
• EEG records demonstrated negligible power line interference, even in challenging electromagnetic interference (EMI) environments.

Conclusions:

• The developed technique is feasible for practical multichannel EEG acquisition.
• The novel DDRL circuit significantly improves the performance of SE amplifier-based EEG systems.
• This approach offers a robust solution for obtaining high-quality EEG data with reduced interference.