基于SYSTEMVIEW的直序扩频通信系统仿真.doc

III题目基于SystemView的直序扩频通信系统仿真摘要扩频通信系统与常规的通信系统相比具有很强的抗干扰能力如抗人为干扰、抗窄带干扰、抗多径干扰等并具有信息隐蔽、多址保密通信等特点已从军事应用向民用通信应用迅速发展。利用SystemView软件作为平台对扩频通信中最典型的扩频工作方式———直接序列扩频系统(DSSS)进行了仿真分析；通过时域波形对比发送端和接收终端两个波形图可明显观察到解扩后的信号与输入的原始信号波形基本一致并注意到接收端有一些毛刺这是由于时间脉冲信号的脉宽有误差而造成的。通过对频谱波形的分析可知扩频系统抗噪声能力很强当不断加大噪声的幅度达到系统的干扰门限时则不能准确地恢复原始信息。结果证明随着扩频增益的增大系统的误码率越小同时扩频系统性能的好坏很大程度上还取决于扩频码的特性。关键词扩频通信仿真SystemViewTitleBasedonTheSystemViewDirectSequenceSpreadSpectrumCommunicationSystemSimulationAbstracThespreadspectrumcommunicationsystemandtheconventionalcommunicationsystemhaveverystrongcomparedtheanti-interferenceabilitysuchasHIVhumaninterferencefightnarrowbandinterferencefightmultipathinterferenceetcandhastheinformationhidingmultipleaddresssecretcommunicationandothercharacteristicsalreadyfrommilitaryapplicationtocivilcommunicationapplicationdevelopingrapidly.UseSystemViewsoftwareplatformtospreadspectrumcommunicationasthemosttypicalspreadspectrumwork--waydirectsequencespreadspectrumsystem(DSSS)areanalyzed;Throughthetimedomainwaveformcontrastthesendingendandreceivingterminaltwowaveformfigurecanobviouslyobservedaftertheexpansionsolutionandtheinputsignaloftheoriginalsignalwaveformandpayattentiontothesameatthereceivingendhassomeburrthisisduetothetimepulsesignalpulsewidthiscausedbytheerror.Throughtheanalysisofthewaveformoffrequencyspectrumitisknownthatspreadspectrumsystemanti-noiseabilityisverystrongwhenrisingoftheamplitudeachievesystemnoiseinterferencethresholditcan'taccuratelyrestoredtheoriginalmessage.Resultsshowthatwiththeincreaseofspreadspectrumgainthesystemberissmallerandspreadspectrumsystemtheperformancetoalargeextentdependsonthecharacteristicsofthecodeisspreadspectrum.KeywordspreadspectrumcommunicationsimulationSystemVi