%function noise1=add_noise(signal_power)
for snr=1:1:20                                                   
to=0.2;                                                             % 接收信號的持續時間     
signal_power = 6225.6;                                              % 信號功率
SIGMA(snr)=sqrt( signal_power /10^(0.1*snr));
noise= zeros(20,2048);
MU = zeros(1,2048);    
noise1(snr,:) = normrnd(MU,SIGMA(snr));  
end
save mydata noise1