dm10505.m

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

% dm10505
% 二阶带阻滤波器的频率响应
b=[1 0 22500];	                %生成向量b
a=[1 200 20000];	            %生成向量a
freqs(b,a);	                    %求频率响应H(jω),并用波特图绘制图形
axis([10 10^3 10^-2 2]);        %调整坐标系范围
%End