A=1;
f=2;

Fs=44100;
P=60;

T=1.0/f;
dt=T/Fs;
N=T/dt;
t=linspace(0,1,N);
y=A*sin(2*pi*f*t+P);

plot(t,y,'r')
% 画正弦函数  y(t)




%获取波形坐标
H=get(gca,'Children');
X=get(H,'xdata');
Y=get(H,'ydata');

Data=[X' Y']



如果你用subplot在一个figure中画了N个坐标，可以这样来提取第n个坐标的数据：
  

H00=get(gcf,'Children');
H=get(H00(n),'Children');
X=get(H,'xdata');
Y=get(H,'ydata');

Data=[X' Y']

谢谢楼主