wn=7;
kosai=[0.1:0.3:2.0];
w=logspace(-1,1,100);
figure(1)
num=[wn^2];
for kos=kosai
    den=[1 2*kos*wn wn^2];
    [mag,pha,w1]=bode(num,den,w);
    subplot(2,1,1);
    hold on
    semilogx(w1,mag);
    subplot(2,1,2);
    hold on
    semilogx(w1,pha);
end
subplot(2,1,1);
grid on
title('Bode 圖');
xlabel('頻率 (rad/sec)');
ylabel('增益 dB');
subplot(2,1,2);
grid on
xlabel('頻率 (rad/sec)');
ylabel('相位 deg');
hold off