各种调制信号的频域测量

论文总字数：19828字

摘 要

通过频域测量，可以获取待测量信号与频率之间的关系。如用频谱分析仪分析信号的频谱测量放大器的幅频特性等，我们通过频域测量可以进入信号内部，可以知道组成信号的频率，幅值，相位以及功率。这样对信号进行频域测量后，我们就可以知道信号里面所含有的更多高次谐波还是低次谐波，在对信号进行滤波时，如何实现硬件电路有重要意义。频域测量是现代通信技术发展的基础。本论文介绍了在计算机环境下，应用MATLAB中的m文件以及仿真的方法进行构建示波器、逻辑分析仪、星座图仪、眼图仪、频谱分析仪等虚拟仪器，对信号进行时域和频谱分析。

关键词: 仿真; 频谱 ; MATLAB ; 时域; 调制

Frequency measurement of all kinds of modulation signal

Abstract

Through the frequency measurement we can get the relationship between the measured signal and frequency. As with the spectrum analysis of spectrum analyzer measuring amplifier signal frequency characteristics, we can enter the internal signal through frequency measurement and know the composition of the signal frequency, amplitude, phase and power. This frequency measurement of the signal, we can know more of the harmonic signal is contained inside or low harmonic, in filtering the signal, how to realize the hardware circuit has important significance. The frequency measurement is the basis for the development of modern communication technology. This paper introduces the application of MATLAB in the computer environment, the m file and the simulation methods of oscilloscope, logic analyzer, constellation analyzer, spectrum analyzer, eye instrument virtual instrument, analysis the time domain and frequency spectrum of the signal.

Keywords: simulation ; spectrum ; MATLAB ; time domain ; modulation

目 录

摘 要..................................................................................................................................................................Ⅰ

Abstract................................................................................................................................................................Ⅱ

第一章 绪 论 1

1.1 课题背景 1

1.2 课题研究的意义 1

1.3 研究思路和方法 1

1.4 本论文结构安排 1

第二章 单边带调制与相干解调 3

2.1 单边带调制原理 3

2.1.1 单边带调制原理..........................................................................................................................3

2.1.2 单边带调制优缺点......................................................................................................................4

2.2 单边带信号的相干解调 4

2.2.1 SSB相干解调的原理...................................................................................................................4

2.2.2 SSB解调的实现...........................................................................................................................5

第三章 信号的时域分析 7

3.1 示波器 7

3.2 逻辑分析仪 7

第四章 频域分析 9

4.1 DFT与FFT原理 9

4.2常用信号的频谱分析 9

4.2.1 ASK调制........................................................................................................................................9

4.2.2 FSK调制.......................................................................................................................................12

4.2.3 PSK调制.......................................................................................................................................14

第五章 通信与广播系统的频域测量 17

5.1 π/4DQPSK调制....................................................................................................................................17

5.1.1 π/4DQPSK调制原理.................................................................................................................17

5.1.2 π/4DQPSK调制频域测量.........................................................................................................17

5.2 QAM调制...........................................................................................................................................19

5.2.1 圆形分布QAM调制.................................................................................................................19

5.2.2 矩形分布QAM调制.................................................................................................................21

5.3 调频立体声...........................................................................................................................................22

5.3.1 调频立体声广播的调制............................................................................................................22

5.3.2 调频立体声广播........................................................................................................................23

5.4 彩色电视信号的频谱编织...................................................................................................................24

第六章 结论......................................................................................................................................................27

致 谢 28

参考文献（References） 29

第一章 绪 论

1.1 课题背景

近些年来,随着电子科学技术的发展,在信号测量领域中,各类示波器以及示波测量仪器的应用越来越广泛。从相对早期的信号定性测量技术发展至今,我们通过示波器就能够清楚观察信号的波形状况,并测量信号的频率、周期以及幅度等,且能够对脉冲信号的上升及下降时间、脉宽以及振铃、上冲等参数进行精确的测量，并且其他非物理量亦可以转换成电量,便于我们使用示波器进行观测。示波器有几个特点是其它仪器所不可替代的。由于电子束的惯性小,因而速度快,工作频率范围宽,适应于测试快速脉冲信号;灵敏度高,因为配有高增益放大器，所以适用于快速脉冲信号的测量。

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