In the daily life, communication is very important for us. Along with development of digital system the technical criterion of modulation and demodulation will be adjusted to meet higher the same time, because of the development of the computing technology, the simulation ofthe communication system has been already popular day by day, it already is main tool of design and analyses system of communication today. This design will use the MATLAB software design function and the simulink modelling carries on the simulation and the research for Phase modulation technology. This article discusses the composition of Communications system,the use of MATLAB and brief introduction of the module of then thorough analysis the principle modulation & use MATLAB and Simulink Carry on the simulation and the research. This design mostly achieves the process simulation of the PSK、QPSK、OQPSK modulation & demodulation ,and analyzes their performance difference. Key words:MATLAB; Modulation and demodulation; PSK;QPSK 目 录 引言……………………………………………………………………………1 1 绪论…………………………………………………………………………2 课题研究的意义 ……………………………………………………………2 国内外研究及发展情况 ……………………………………………………2 本课题主要内容 ……………………………………………………………4 2 通信系统和调相信号研究及MATLAB简介……………………………4 通信系统的组成…………………………………………………………4 ……………………………………………………………5 调相技术的初步研究…………………