幅度响应1501005000.10.20.30.50.6频率?(x? rad/sample0.40.70.80.9相位响应80604020000.10.20.30.50.6频率?(x? rad/sample0.40.70.80.9
Eg5.18(1) 代码如下：
b=[1 0];a=[1 0.9]; figure(1);zplane(b,a); n=0:40;figure(2); subplot(2,1,1)
h=impz(b,a,n);mystem(n,h) xlabel('k') title('冲激响应') subplot(2,1,2)
g=stepz(b,a,n);mystem(n,g) xlabel('k') title('阶跃响应') [H,w]=freqz(b,a); figure(3);subplot(2,1,1) myplot(w/pi,abs(H));
xlabel('频率\\omega(x\\pi rad/sample)') title('幅度响应') subplot(2,1,2)
myplot(w/pi,unwrap(angle(H)*180/pi)) xlabel('频率\\omega(x\\pi rad/sample)') title('相位响应')
结果：
10.80.60.4Imaginary Part0.20-0.2-0.4-0.6-0.8-1-1-0.50Real Part冲激响应10.50-0.5-105101520k253035400.51阶跃响应10.80.60.40.205101520k25303540幅度响应108642000.10.20.30.50.6频率?(x? rad/sample)0.40.70.80.9相位响应604020000.10.20.30.50.6频率?(x? rad/sample)0.40.70.80.9
Eg5.18(2) 代码如下：
b=[1 0];a=[1 -0.9]; figure(1);zplane(b,a); n=0:40;figure(2); subplot(2,1,1)
h=impz(b,a,n);mystem(n,h) xlabel('k') title('冲激响应') subplot(2,1,2)
g=stepz(b,a,n);mystem(n,g) xlabel('k') title('阶跃响应') [H,w]=freqz(b,a); figure(3);subplot(2,1,1) myplot(w/pi,abs(H));
xlabel('频率\\omega(x\\pi rad/sample)') title('幅度响应') subplot(2,1,2)
myplot(w/pi,unwrap(angle(H)*180/pi)) xlabel('频率\\omega(x\\pi rad/sample)') title('相位响应')
结果：
10.80.60.4Imaginary Part0.20-0.2-0.4-0.6-0.8-1-1-0.50Real Part冲激响应10.80.60.40.2005101520k253035400.51阶跃响应10864205101520k25303540
