实验四线性时不变离散时间系统的频域分析.doc

Name:Chen yifan 20112121006
Section:
Laboratory Exercise 4
LINEAR, TIME-INVARIANT DISCRETE-TIME SYSTEMS: FREQUENCY-DOMAIN REPRESENTATIONS
TRANSFER FUNCTION AND FREQUENCY RESPONSE
Project Transfer Function Analysis
Answers:
The modified Program P3_1 pute and plot the magnitude and phase spectra of a moving average filter of Eq. () for 0 w 2p is shown below:
< Insert program code here. Copy from m-file(s) and paste. >
w=0:pi/511:2*pi;
M=input('M= ');
num=ones(1,M)/M;
h=freqz(num,1,w);
subplot(2,1,1);
plot(w/pi,abs(h));grid;
title('H(e^{j\omega})幅度谱');
xlabel('\omega/\pi');ylabel('振幅');
subplot(2,1,2);
plot(w/pi,angle(h));grid;
title('相位谱 H(e^{j\omega})');
xlabel('\omega/\pi');ylabel('以弧度为单位的相位');
This program was run for the following three different values of M and the plots of the corresponding frequency responses are shown below:
< Insert MATLAB figure(s) here. Copy from figure window(s) and paste. >
The types of symmetries exhibited by the magnitude and phase spectra are due to -
The type of filter represented by the moving average filter is
M=3
-
M=10;
M=20;
The results of Question can now be explained as follows - By the graph, you can see that it represents a low-pass filter.
The plot of the frequency response of the causal LTI discrete-time system of Question obtained using the modified program is given below:
< Insert MATLAB figure(s) here. Copy from figure window(s) and paste. >
w=0:pi/511:pi;
num=[ 0 -];
den=[1 - ];
h=freqz(num,den,w);
subplot(2,1,1);
plot(w/pi,abs(h));grid;
title('H(e^{j\omega})幅度谱');
xlabel('\omega/\pi');ylabel('振幅');
subplot(2,1,2);
plot(w/pi,angle(h));grid;
title('相位谱 H(e^{j\omega})');
xlabel('\omega/\pi');
ylabel('以弧度为单位的相位');
The type of filter represented by this transfer function is - It says bandpass filter is obtained by diagrams can be BPF
The plot of the frequency response of the causal LTI discrete-time system of Question Q4