1. 6 Time and Frequency Characterization of Signals and Systems
6.0 Introduction
Meanings of the Fourier Transform of a CT signal
Magnitude-Spectrum and Phase-Spectrum
( The magnitude and phase angle of the CTFT )
Meanings of the Frequency response of a LTI system
The magnitude and phase shift of the frequency response
(The magnitude-frequency and phase-frequency characteristics)
The distortionless transmission-system
The Time and Frequency-domain properties of Frequency-Selective Filters
Time and Frequency-domain properties of First and Second-Order systems

2. 6.1 The Magnitude-Phase Representation of The Fourier Transform

3. Magnitude-Spectrum/ The magnitude of the CTFT :
The complex magnitude of the frequency component is:
The relative complex magnitude is

4. Phase-Spectrum/ The phase angle of the CTFT :
The complex magnitude of the frequency component is:
The relative complex magnitude is

6. xt=cos(0.56*pi*t)+cos(0.28*pi*t)+cos(t);
clear all; t=-4:0.05:4;
xt=cos(0.56*pi*t)+cos(0.28*pi*t)+cos(t);
plot(t,xt,'b'); xlabel('t'); hold on
y1t=cos(0.56*pi*t-pi/3)+cos(0.28*pi*t-2*pi/3)+cos(t-pi/2);
plot(t,y1t,'r');
y2t=cos(0.56*pi*(t-0.5*pi/2))+cos(0.28*pi*(t-0.5*pi/2))+cos(t-0.5*pi/2);
plot(t,y2t,'c');title('x(t),y1(t),y2(t)');hold off

7. clear all; t=-4:0.05:4;
xt=cos(0.56*pi*t)+cos(0.28*pi*t)+cos(t);
plot(t,xt,'b'); xlabel('t'); hold on
y1t=0.25*cos(0.56*pi*t)+0.5*cos(0.28*pi*t)+cos(t); plot(t,y1t,'r')
y2t=cos(0.56*pi*t)+0.5*cos(0.28*pi*t)+0.25*cos(t);
plot(t,y2t,'c');title('x(t),y1(t),y2(t)'); hold off

8. 6.2 The Magnitude-Phase Representation of The Frequency Response of LTI Systems

9. The magnitude of the frequency response / The magnitude-frequency characteristic:
The effect an LTI system has on the magnitude of the FT of a input signal is to scale it by the magnitude of the frequency response

10. The phase shift of the frequency response / The phase -frequency characteristic:

11. 6.2.1 The distortionless transmission-system

12. 6.2.1 The distortionless transmission-system

13. xt=cos(0.56*pi*t)+cos(0.28*pi*t)+cos(t);
clear all; t=-4:0.05:4;
xt=cos(0.56*pi*t)+cos(0.28*pi*t)+cos(t);
plot(t,xt,'b'); xlabel('t'); hold on
y1t=cos(0.56*pi*t-pi/3)+cos(0.28*pi*t-2*pi/3)+cos(t-pi/2);
plot(t,y1t,'r');
y2t=cos(0.56*pi*(t-0.5*pi/2))+cos(0.28*pi*(t-0.5*pi/2))+cos(t-0.5*pi/2);
plot(t,y2t,'c');title('x(t),y1(t),y2(t)');hold off

14. clear all; t=-4:0.05:4;
xt=cos(0.56*pi*t)+cos(0.28*pi*t)+cos(t);
plot(t,xt,'b'); xlabel('t'); hold on
y1t=0.25*cos(0.56*pi*t)+0.5*cos(0.28*pi*t)+cos(t); plot(t,y1t,'r')
y2t=cos(0.56*pi*t)+0.5*cos(0.28*pi*t)+0.25*cos(t);
plot(t,y2t,'c');title('x(t),y1(t),y2(t)'); hold off

16. SAS实验三 线性失真的计算机仿真与分析 内容 1 无失真传输系统的概念，应满足的条件； 2 幅度失真的涵义，仿真分析；
3 相位失真的涵义，仿真分析；
4 幅度、相位失真的仿真分析；
5 总结 要求
1 理论分析完整、严谨；
2 仿真条件表述清晰，仿真结果具有说服力；
3 以学术论文格式写作。
文档类型：Word或PPT文档
文件名：学号_姓名_实验3