global t;
global t1;
global t2;
global t0;
global y;
global y1;
global N;
p=str2num(get(handles.gonglv,'string'));
t1=str2num(get(handles.startt,'string'));
t2=str2num(get(handles.endt,'string'));
Ts=0.01;
fs=1/Ts;
t=-(t2-t1)/2:Ts:(t2-t1)/2;
y=wgn(1,length(t),p);
y1=xcorr(y);
N=length(y1);
y1=fft(y1);
y1=fftshift(y1);
t0=-(t2-t1):Ts:(t2-t1);
t0=2*pi*fs/N*t0;