Analog Matched Filtering Technique for SSVEP Detection : Hardware Overview

Abstract

Steady-state visual evoked potential (SSVEP) is an electroencephalogram (EEG) activity elicited by continuous flickering of visual stimulus. These are oscillatory electrical potential that are evoked in the brain when the person is visually focusing his/her attention on a visual stimulus that is flickering at frequency 10 Hz and above. SSVEP has been intensively adopted in braincomputer interfaces to map the human brain activity with computers or external devices. These signals are strong in occipital region (visual cortex) of the brain and are nearly sinusoidal waveform having the same fundamental frequency as the visual stimulus. The detection of this frequency can be achieved by a method of matched filtering, in which the matching/correlation of extracted evoked SSVEP signal frequency from the brain with the corresponding stimulated one. The approach presented in this document, to detect the frequency information of the visual stimulus from the evoked noisy EEG signal is using based on quadrature analog matched filtering technique. The hardware details of the matched filtering and it’s test results are presented in this report.