华科学院HUAKE INSTITUTE OF TAIYUAN UNIVERSITY OFSCIENCE & TECHNOLOGY外文翻译题目：扩频通信系统及MATLAB仿真学 生 姓 名 学 号 班 级 通信072201H 所属院（系） 电子信息工程系 指 导 教 师 2011年6月Spread Spectrum Communication System and MATLAB SimulationABSTRACTThis thesis expounds the basic principles of spread spectrum communication , and then the article mainly acts according to the Shannon theorem and tan oak Czechoslovakia you Nepal may the husband latent antijamming theory,With the aid of MatLab toolbox and Monte Carlo simulation algorithm,it has established the direct sequence spread spectrum communications system simulation model which does not have when the disturbance through the analysis error rate simulation curve and theory predicted value,had proven constructs the simulation model the accuracy.Key words：Spread spectrum；communication；MATLAB1 Introduction1.1 Spread Spectrum Communication SystemSpread spectrum communication, namely, spread spectrum communications (Spread Spectrum Communication), with fiber-optic communications, satellite communications, with access to the information age as the three major high-tech communications transmission.Spread spectrum communication is to send the information to be pseudo-random data is coded (spread spectrum sequence: Spread Sequence) modulation, spread spectrum and then the realization of transmission; the receiving end is using the same modem code and related processing, the restoration of the original data.Spread spectrum communication system has three main characteristics.Carrier is an unpredictable, or so-called pseudo-random broadband signal.Carrier data bandwidth than the modulation bandwidth is much wider.Receiving process is generated by local broadband carrier signal and receiving a copy of the signal to the broadband signal to achieve.The main way of spread spectrum are as follows:Direct Sequence Spread Spectrum (DSSS) using high-speed pseudo-random code on to the low-speed data transmission spread spectrum modulation;Frequency-hopping system using pseudo-random code to control the carrier frequency in a wider band of the change;TH is the data transmission time slot is a pseudo-random;Chirp frequency system is a linear extension of the process of change.Combination of a number of ways of hybrid systems are often applied.The most important measure of spread-spectrum system is an indicator of spreading gain, also known as processing gain.It is precisely because of the spread spectrum system itself with its performance characteristics with a series of advantages.1.2 The purpose of spread spectrum communication studies and significance Spread spectrum communication is an important branch of communication and channel the direction of development of communication systems.Spread-spectrum technology, with strong anti-interference ability, confidentiality, and is easy to realize the advantages of multiple-access communications, so the technology is receiving increasing attention.In recent years, with very large scale integrated circuit technology, the rapid development of microprocessor technology, as well as the application of some new components, spread spectrum communications is technically feasible to enter a new level, not only in an important military communications status, and are quickly penetrated into the personal communications and computer communications and other civilian areas, to become the new century, the most potential of communication technologies.The study is spread spectrum communication with far-reaching significance, I through the thesis the design, conduct in-depth study of the spread spectrum communication technology and its applications for simulation, knowledge will be summarized and summed in order to consolidate the basic knowledge of communications for the After the individual to lay a foundation to study and work.2 The basic principles of spread spectrum communication2.1 The definition of spread spectrum communicationThe so-called spread spectrum communications, can be simply expressed as follows:Spread spectrum communication technology is a means of information transmission,Share some of its signal bandwidth is much larger than the minimum mass of information necessary bandwidth;The expansion of the band through a separate code sequence to complete, using the method of coding and modulation to achieve, with the mass of information has nothing to do;Receiving end in the same synchronization code related to receiving, despreading and recovery of the mass data. This definition includes the meaning of the following three aspects: 1)The signal spectrum by a broadening.We know that the transmission of any information needs to a certain bandwidth, as the information bandwidth.For example, the human voice information bandwidth of 300Hz - 3400Hz, television image information bandwidth of MHz.In order to make full use of frequency resources, which are roughly the same a