Non-invasive electroencephalography (EEG) operates in the microvolt regime (5 to 100 µV). Powerline 50/60 Hz hum, Wi-Fi emissions, and switch-mode power supplies severely corrupt raw scalp potentials. This engineering study outlines active shielding, isolated analog grounds, and digital notch filters for clean clinical signals.
Buffering the EEG signal directly at the scalp electrode with sub-picoampere bias current op-amps eliminates cable capacitance effects, raising common-mode rejection by over 30 dB.
Shielding the BLE radio module inside an isolated grounded aluminum compartment prevents 2.4 GHz RF bursts from coupling into sensitive high-gain biopotential amplifier stages.