摘 要：针对通信领域频谱利用率提高的需求，本文采用 MATLAB 工具，设计开发了多进制 正交幅度调制(MQAM)数字调制系统。多进制正交幅度调制(MQAM)是一种频谱利用率和功率 密度较高的数字调制技术，在通信领域有着广泛的运用。论文着重论述了 MQAM 正交幅度 调制解调方式，通过系统实验对正交幅度调制解调的过程、原理及性能进行了论证、分析， 并根据星座图的形状指出了 MQAM 在调制与解调方法上的区别，理论上讨论和说明了数字 调制解调技术中影响系统性能的条件和因素，并通过眼图进行了简单观察。最后利用仿真 软件 MATLAB 对 MQAM 全数字调制与解调过程进行了仿真，并给出了 MQAM 在加性高斯白噪 声条件下的误码率实验及仿真，结果证明全数字正交幅度调制解调易于实现，且性能良好， 是未来通信技术的主要研究方向之一，并有广阔的应用前景。75417

毕业论文关键词：QAM，调制解调，MATLAB，误码率

Abstract: Aiming at the demand of spectrum utilization in the communication domain, this paper designed and developed a Multiple Quadrature Amplitude Modulation (MQAM) digital modulation system based on the MATLAB tool。 Multiple Quadrature Amplitude Modulation (MQAM) is a kind of spectrum utilization efficiency and higher power density  digital modulation technology。 It has been widely used in the field of communications。 This thesis emphatically discusses the MQAM quadrature amplitude modulation demodulation way, through the system experiments of quadrature amplitude modulation demodulation process, analyses and demonstrates the principle and performance。 According to the shape of the constellation diagram, MQAM are pointed out in the difference between the modulation and demodulation method, theoretically discusses and illustrates the digital modulation demodulation technology of the conditions and factors that influence the performance of the system, and has carried on  the simple observation through the eye diagram。 Finally  it uses the  simulation software  MATLAB to simulate MQAM digital modulation and demodulation process, and presents the additive error rate experiment and simulation of the experiment and simulation under the condition of additive white Gaussian noise, finally proves that the digital quadrature amplitude modulation demodulation is easy to implement, and has good performance。 It is one of the main research directions   of future   communication  technology,   and has  a broad application prospects。

Keywords:  QAM, modulator  and demodulator,   MATLAB,  bit  error rate

目 录

1 绪论 4

1。1 课题的背景及意义 4

1。2 QAM 的研究现状 4

1。3 课题研究的主要内容 5

2 正交幅度调制解调原理 5

2。1 引言 5

2。2 QAM 调制解调原理 5

2。3 MQAM 调制解调原理 7

2。4 结语 7

3 MATLAB/SIMULINK 的简介 8

4 仿真及实现说明