dm10501.m

the code of the book come form the book of marlix laboratory with the book of singal

%dm10501
%应用freqs函数求频率响应并作图
B = [0 1 3];	                             %生成向量B
A = [1 3 2];	                             %生成向量A
W = 0:0.5:2*pi;                              %生成向量W
H = freqs(B,A,W);                            %计算0~2π频率范围内以间隔0.5采样的系统频率响应的样值
HM = abs(H);                                 %求幅度响应
HP = angle(H);                               %求相位响应
subplot(211);
plot(W/pi,HM);                                %绘制幅度响应
xlabel('\omega  单位:(pi)');
title('幅度响应');
axis([0 2 0 2]);
subplot(212);
plot(W/pi,HP*180/pi);                         %绘制相位响应
xlabel('\omega  单位:(pi)');
title('相位响应');
axis([0 2 -100 10]);
%End