基于simulink调制解调器设计 毕业设计1.doc

基于simulink设计QPSK调制解调器 摘 要 本文介绍了一种基于simulink设计的QPSK调制解调器，现代通信系统要求通信距离远、通信容量大、传输质量好。作为其关键技术之一的调制解调技术一直是人们研究的一个重要方向。从模拟调制到数字调制，从二进制发展到多进制调制，虽然调制的方式多种多样，但都是朝着使通信系统更高速、更可靠的方向发展。一个系统的通信质量，很大程度上依赖于所采用的调制方式。在数字通信中，常采用频移键控（FSK）和相移键控（PSK）这两种方法对数字信号进行调制解调，从而达到传递数字信息的目的。 目前，相移键控（PSK）一般采用四相和多相制。相移键控(PSK)是一个数字调制方案，传递数据，改变或者调制阶段的载波信号。所有的数字调制方案利用有限的许多独特的信号来代表数字数据。用PSK有限数目的阶段，每个阶段分配一个唯一的二进制数字模式。一般情况下，各相位编码的比特数相等。每一个模式的位元符号的形式是特定的阶段。这种解调器，其目的是特别为使用的symbol-set调制器，决定阶段的接收信号和返回的符号，它也就代表了调制解调的输出数据，从而恢复到原始数据。这就要求接收器能够比较接收信号的参考信号——这样一个系统被称为相干(或被称为CPSK)。本文就四相制移相键控（QPSK）技术的概念，应用和原理方面进行了详细介绍。并且对QPSK?进行了系统仿真和实现方面也做了详尽的阐述。? 关键词：相移键控；四相移键控；QPSK调制；相干解调 Simulation design of QPSK modem based on simulink Abstract This paper describes a design based on simulink QPSK modems, modern communication systems require communication distance, large communication capacity, better transmission quality. As one of the key technologies of modem technology it has been an important direction for researchers. From analog modulation to digital modulation, binary-ary modulation development, although modulation variety of ways, but they are moving in make communications systems more speed, more reliable direction. The communication quality of a system depends heavily on the modulation scheme used. In digital communication, often using frequency shift keying (FSK) and phase shift keying (PSK) both methods of digital signal modulation and demodulation, so as to achieve the purpose of transmitting the digital information. At present, phase shift keying (PSK) generally use the four-phase and multiphase system. Phase shift keying (PSK) is a digital modulation scheme, data transfer, or changing the phase of the modulated carrier signal. All digital modulation scheme uses a limited number of unique signals to represent digital data. PSK with a limited number of stages, each stage is assigned a unique binary digital mode. In general, an equal number of bits of each phase encoding. In the form of a pattern of bits per symbol i