FSK-SSVEP System Based on EMD and Non-coherent Demodulation Algorithm
Zhao Dechun
Wang Xia
Feng Mingyang
Li Xiaoxiang
Abstract：Objective To realize the EEG signal acquisition and processing,and the accurate demodulation of the steady-state visual evoked potential (SSVEP) signal based on coded stimulus.Methods The frequency shift keying (FSK) coding strategy in digital communication was adopted to encode the SSVEP stimulation frequency.The 4 rows and 4 columns LED arrays were used in the stimulator and the SSVEP signal in the EEG signal was accurately extracted.The empirical mode decomposition (EMD) was applied to preprocess the extracted SSVEP signal to improve the signal-to-noise ratio of the acquired signal.With the traditional FSK demodulation algorithm,the non-coherent demodulation,was used to realize the frequency decoding.Results The average accurate rate of demodulation in the FSK-SSVEP system was over 90％ in 10 volunteers participant in the experiment.Conclusion The system based on EMD and non-coherent demodulation algorithm could achieve high accurate rate of demodulation;and the FSK encoding mechanism could solve the problem that the stimulation frequency of the traditional SSVEP-based brain-computer interface (SSVEP-BCI) system is limited by the stimulator refresh rate and the available modulation frequency is lacking.
Keywords：frequency shift keyingsteady-state visual evoked potentialempirical mode decompositiondemodulation
Publication Date：2019-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：8( 95-102 )