【关键词】 Matlab QPSK Simulnk 仿真
ABSTRACT
In the 21st world of the rapid development of the information age, each country
to communication industry is spare no effort to support. The 3 g industry in our
country as vigorous development, the country should be advocated and three nets
fusion. Good technology can quickly transfer user information, and has a high
accuracy (that is, very low bit error rate) and reliability. QPSK demodulation
technology with its high demodulation rate, low error rate, in CDMA areas to be
widely applied. The paper presents the design of this paper mainly introduces the
photograph is shift keying (QPSK) profile, and positive photograph shift keying
(QPSK) modulation demodulation concept and principle, transmission bit error rate
and symbol error rate calculation, understand involved in Simulink QPSK various
modules function. The QPSK modulation demodulation adopted orthogonal
modulation and coherent demodulation, contains the string and conversion, level
conversion, carrier modulation, signal synthesis, coherent demodulation, sampling
judgment, and string conversion a series of system design, and use the Matlab
Simulink module for QPSK modulation demodulation system simulation, the QPSK
white gaussian noise channel in the performance analysis, and then verify the QPSK
modulation technology superiority.
【Key words】Matlab QPSK Simulink Simulation
二、设计目的和意义
（1）通过完成专业方向的设计内容，加深对通信原理理论的理解，熟悉通
信系统的基本概念，复习正交相位偏移键控(QPSK)调制解调的基本原理和误比
特率的计算方法，了解调制解调方式中最基础的方法。
（2）学会使用 MATLAB 中的 simulink 仿真软件，了解其各种模块的功能，
用 simulink 实现 QPSK 的调制和仿真过程，得到调制信号经高斯白噪声信道，再
通过解调恢复原始信号，分析 QPSK 在高斯信道中的性能，计算传输过程中的误
码率。通过此次设计，在仿真中形象的感受到 QPSK 的调制和解调过程，有利于
深入了解 QPSK 的原理。
（3）通过 Simulink 建模完成 QPSK 调制解调系统的仿真，以及误码率测试，
通过整个仿真建模的系统了解 QPSK 整个的调制解调流程，并通过示波器观察各
点的波形，拿得出的响应波形与理论波形进行比较，分析仿真的结果。
（4）掌握了 simulink 的使用，增强了我们学习通信的兴趣，培养通信系统
的仿真建模能力。
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