基于matlab的载波同步,2011毕设--论文--基于MATLAB的通信系统仿真程序设计—QPSK与同步--贺铮.docx...

2011毕设--论文--基于MATLAB的通信系统仿真程序设计—QPSK与同步--贺铮

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河南科技大学本科毕业设计(论文)

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基于MATLAB的通信系统仿真程序设计

——QPSK与同步

摘 要

介绍了数字通信中的QPSK调制、同步和解调的原理,通过用MATLAB编写脚本程序对QPSK通信系统的发射、同步和接收过程的具体实现进行模拟仿真,并运行M文件绘出信号在理想信道和加噪信道中模拟传输时的时域图,并对各模块进行了频谱分析,所得到的结果与理论基本相符,对于理解QPSK系统的性能并在系统的实际应用上作进一步的设计,提供了有效的参考依据。

本文首先介绍了数字通信的原理及其发展历史，然后研究了目前通信领域中广泛采用的QPSK调制，并利用MATLAB这一强大的软件，通过M函数的编写，进行软件仿真，包括调制、同步和解调。得出了相应的波形与频谱，并进行了简单的分析。由于强调了几种同步的重要性，建立了一种QPSK并行解调模型,并对定时同步、载波同步等各个模块进行了MATLAB仿真分析。提出了一套方案,重点提出了一种解决并行解调中载波同步后模糊不统一问题的重编码新方法。建立了一种QPSK并行解调模型,并对定时同步、载波同步等各个模块进行了MATLAB仿真分析。提出了一套方案,重点提出了一种解决并行解调中载波同步后模糊不统一问题的重编码新方法。

关键词：数字通信,MATLAB，QPSK，同步

Design and Simulation for QPSK System Based on MATLAB

Abstract

The introduction was done with the principle of the QPSK modulation，synchronize and demodulation in digital communications, a script was written by using MATLAB program to carry out a simulation of the QPSK communication system, which contains the concrete realization of transmit， synchronize and receive process. Base on the M file. The time domain diagram is drew separately when the signal transmits in the ideal channel and in the channel with noise, spectral analysis of each module is also done, the results obtained with theoretical results in the main, which provides an effective frame of reference for understanding the performance of QPSK systems, and the practical application in the system to make further designed.

This paper introduces the digit communication rationale of the QPSK and it history, The QPSK modulation which are widely used in current wireless communication, it also simulates the process through M- file programming with the powerful software-MATLAB, and shows the results of corresponding waveform and spectrum. And analyze it. Here I emphasize a kinds of method of synchronize, A kind of parallel demodulation model for QPSK signals is designed, and the modules of the model including timing synchronization, carrier synchronization are simulated. A method of is given. Especially, a new method called recoding for phase ambiguity