Short-time Fourier Transform analysis of EEG signal generated during imagined writing

Short-time Fourier Transform (STFT) analysis is one of the techniques to reveal the frequency contents of the EEG signals at each time point. This information can be used to provide control and perform several tasks using Brain Computer Interface system (BCI). This paper describes the STFT analysis of EEG signals obtained during writing and imagined writing. The EEG signal was filtered using a bandpass filter with a frequency range of 8-30 Hz before the STFT was computed. The width of the Hamming window used in the STFT computation was varied to obtain the optimum width. The results of the STFT analysis showed that the frequency components of the EEG signals obtained from writing are the same as that obtained during imagined writing.