如何在eeg信号中插入awgn噪声？

Question

我已下载.mat类型的文件并将其导入matlab，现在我想在该eeg信号中添加噪音。

>fs = 512
>T = 1/fs; % sampling rate or frequency;
>N =length(EEGsig);
>ls = size(EEGsig); % find the length of the data per second
>tx =[0:length(EEGsig)-1]/fs;
>fx = fs*(0:N/2-1)/N;
>figure; subplot (211), plot(tx,EEGsig); xlabel('Time (s)'), 
>ylabel('Amplitude (uV)'), title('Original EEG signal');  %EEG waveform
>subplot(212), plot(tx,EEGsig);
>xlabel('Time (s)'), ylabel('Amplitude (uV)'), title('Zoom into original EEG 
signal at 1 to 2 seconds'), xlim([1,2]) ; % Used to zoom in on single ECG 
waveformfigure

<biomedical signal processing>