[h0,h1]=meshgrid([-4:0.2:4]);   %確定濾波器系數H(n)的范圍
J=0.55+h0.^2+h1.^2+2*h0.*h1*cos(pi/8)-sqrt(2)*h0*cos(pi/10)-sqrt(2)*h1*cos(pi/40*9);
                                %計算各組系數下的誤差性能J(H)
axis([-4,4,-4,4]);
hold on;
contour(h0,h1,J,100);           %繪制誤差性能曲面的二維等高線
xlabel('h0');
ylabel('h1');

A=[linspace(0,0,102); linspace(0,0,102)];
A=A';
for i=0:99                      %100次LMS迭代實驗
    S=sqrt(0.05)*randn(1000,1);
    H=[3; -4];
    T=H';
    e=0;
    for n=0:1:100
        y=sin(pi/8*(n+1)+pi/10)+S(n+1,:);
        e=y-H'*[sqrt(2)*sin(pi/8*(n+1)); sqrt(2)*sin(pi/8*n)];
        H=H+0.4*e*[sqrt(2)*sin(pi/8*(n+1)); sqrt(2)*sin(pi/8*n)];
        T=[T; H'];
    end
    A=A+T/100;                  %所有H(n)軌跡取平均值
end
A=A';
plot(A(1,:),A(2,:),'r');        %繪制H(n)平均值的軌跡曲線