实验五:离散时间系统的频域分析
一、实验目的:
1、加深对离散系统的频率响应分析的理解;
2、加深对零、极点分布的概念理解。
二、实验内容:
1、 系统传输函数和频率响应;
2、 系统传输函数的类型;
3、 系统稳定性测试;
4、 语音信号的语谱分析
三、实验例程
1、用MATLAB 研究滤波器的特性,先产生滤波器的冲激响应,然后产生零极点图,
最终显示出零点的位置。
clf;
b = [1 -8.5 30.5 -63];
num1 = [b 81 fliplr(b)];
num2 = [b 81 81 fliplr(b)];
num3 = [b 0 -fliplr(b)];
num4 = [b 81 -81 -fliplr(b)];
n1 = 0:length(num1)-1;
n2 = 0:length(num2)-1;
subplot(2,2,1); stem(n1,num1);
xlabel(\'Time index n\');ylabel(\'Amplitude\'); grid;
title(\'Type 1 FIR Filter\');
subplot(2,2,2); stem(n2,num2);
xlabel(\'Time index n\');ylabel(\'Amplitude\'); grid;
title(\'Type 2 FIR Filter\');
subplot(2,2,3); stem(n1,num3);
xlabel(\'Time index n\');ylabel(\'Amplitude\'); grid;
title(\'Type 3 FIR Filter\');
subplot(2,2,4); stem(n2,num4);
xlabel(\'Time index n\');ylabel(\'Amplitude\'); grid;
title(\'Type 4 FIR Filter\');
pause
subplot(2,2,1); zplane(num1,1);
title(\'Type 1 FIR Filter\');
subplot(2,2,2); zplane(num2,1);
title(\'Type 2 FIR Filter\');
subplot(2,2,3); zplane(num3,1);
title(\'Type 3 FIR Filter\');
subplot(2,2,4); zplane(num4,1);
title(\'Type 4 FIR Filter\');
disp(\'Zeros of Type 1 FIR Filter are\');
disp(roots(num1));
disp(\'Zeros of Type 2 FIR Filter are\');
disp(roots(num2));
disp(\'Zeros of Type 3 FIR Filter are\');
disp(roots(num3));
disp(\'Zeros of Type 4 FIR Filter are\');
disp(roots(num4));
Zeros of Type 1 FIR Filter are
2.9744
2.0888
0.9790 + 1.4110i
0.9790 - 1.4110i
0.3319 + 0.4784i
0.3319 - 0.4784i
0.4787
0.3362
Zeros of Type 2 FIR Filter are
3.7585 + 1.5147i
3.7585 - 1.5147i
0.6733 + 2.6623i
0.6733 - 2.6623i
-1.0000
0.0893 + 0.3530i
0.0893 - 0.3530i
0.2289 + 0.0922i
0.2289 - 0.0922i
Zeros of Type 3 FIR Filter are
4.7627
1.6279 + 3.0565i
1.6279 - 3.0565i
-1.0000
1.0000
0.1357 + 0.2549i
0.1357 - 0.2549i
0.2100
Zeros of Type 4 FIR Filter are
3.4139
1.6541 + 1.5813i
1.6541 - 1.5813i
-0.0733 + 0.9973i
-0.0733 - 0.9973i
1.0000
0.3159 + 0.3020i
0.3159 - 0.3020i
0.2929 |