【正文】 robability formula: ）（ 0j /fow NEP ? （ 3） Where: jPow Error Probability E Signal energy 0N Noise power spectral density Signal power TEP /? (T for the duration of information) Noise Power 0WNN? (W for the signal band width) Information bandwidth TDF /1? The type (3) can be translated into: )//(/ow FWNPfNPTWfP ????? ）（ （ 4） (4) shows that for a certain bandwidth of the information in terms of DF , with PG values greater broadband signal transmission, antiinterference ability can improve munications to ensure that under conditions of strong interference, safe and reliable is, (4) and type (2) the same signal to noise ratio and bandwidth that can be interchangeable. In short, we use the information bandwidth of 100 times, or even 1000 times higher than the broadband signal to transmit the message that in order to improve the munication of antiinterference ability, that is in strong interference conditions to ensure safe and reliable is the spreadspectrum munications based on the basic ideas and theories. Spread Spectrum Communication39。The expansion of the band through a separate code sequence to plete, using the method of coding and modulation to achieve, with the mass of information has nothing to do。TH is the data transmission time slot is a pseudorandom。 the receiving end is using the same modem code and related processing, the restoration of the original spectrum munication system has three main characteristics. Carrier is an unpredictable, or socalled pseudorandom 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 highspeed pseudorandom code on to the lowspeed data transmission spread spectrum modulation。 華科學(xué)院 HUAKE INSTITUTE OF TAIYUAN UNIVERSITY OF SCIENCE amp。 TECHNOLOGY 外文翻譯 題目： 擴(kuò)頻通信系統(tǒng)及 MATLAB 仿真 學(xué) 生 姓 名 學(xué) 號 班 級 通信 072201H 所屬院（系） 電子信息工程系 指 導(dǎo) 教 師 2021 年 6 月 1 Spread Spectrum Communication System and MATLAB Simulation ABSTRACT This thesis expounds the basic principles of spread spectrum munication , 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 munications 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； munication； MATLAB 1 Introduction Spread Spectrum Communication System Spread spectrum munication, namely, spread spectrum munications (Spread Spectrum Communication), with fiberoptic munications, satellite munications, with access to the information age as the three major hightech munications spectrum munication is to send the information to be pseudorandom data is coded (spread spectrum sequence: Spread Sequence) modulation, spread spectrum and then the realization of transmission。Frequencyhopping system using pseudorandom code to control the carrier frequency in a wider band of the change。Chirp frequency system is a linear extension of the process of 2 of a number of ways of hybrid systems are often applied. The most important measure of spreadspectrum system is an indicator of spreading gain, also known as processing is precisely because of the spread spectrum system itself with its performance characteristics with a series of advantages. The purpose of spread spectrum munication studies and significance Spread spectrum munication is an important branch of munication and channel the direction of development of munication technology, with strong antiinterference ability, confidentiality, and is easy to realize the advantages of multipleaccess munications, so the technology is receiving increasing recent years, with very large scale integrated circuit technology, the rapid development of microprocessor technology, as well as the application of some new ponents, spread spectrum munications is technically feasible to enter a new level, not only in an important military munications status, and are quickly perated into the personal munications and puter munications and other civilian areas, to bee the new century, the most potential of munication study is spread spectrum munication with farreaching significance, I through the thesis the design, conduct indepth study of the spread spectrum munication technology and its applications for simulation, knowledge will be summarized and summed in order to consolidate the basic knowledge of munications for the After the individual to lay a foundation to study and work. 2 The basic principles of spread spectrum munication The definition of spread spectrum munication The socalled spread spectrum munications, can be simply expressed as follows:Spread spectrum munication technology is a means of information transmission,Share some of its signal bandwidth is much larger than the minimum mass of information necessary bandwidth。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 example, the human voice information bandwidth of 300Hz 3 34