ex1603.m

数字信号处理的MATLAB实现

%例16-3 外插运算方法和误差
x = 0:10;
y = sin(x);
xi=5:0.25:15;
yi=sin(xi);
y1=interp1(x,y,xi,'nearest')
y1=interp1(x,y,xi,'nearest','extrap');
y2=interp1(x,y,xi,'linear','extrap');
y3=interp1(x,y,xi,'spline','extrap');
y4=interp1(x,y,xi,'cubic','extrap');
y5=interp1(x,y,xi,'cubic',0);
plot(x,y,'o',xi,yi,xi,y1,xi,y2,xi,y3,xi,y4,xi,y5)	%各种外插结果，如图16-5
legend('data','sin','nearest','linear','spline','cubic','0',2)	%在左上方标注
table=[xi',yi',y1',y2',y3',y4',y5'];
n=size(table,1);
table([1:10,n-10:n],:) 		%比较各种算法的内插和外插结果