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1、河南师范大学本科毕业论文******大学本科毕业论文学号:110******话音信号的2DPSK调制系统27河南师范大学本科毕业论文摘要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技术一直是人们研究的一个重要方向。从最早的模拟调幅调频技术的日臻完善,到现在数字调制技术的广泛运用,使得信息的传输更为有效和可靠。在二进制数字调制中,当正弦载波的相位随二进制数字基带信号离散变化时,则产生二进制移相键控(2PSK)信号。因为在调制过程中,2PSK调制容易出现反向工作问题,影响2PSK信号长距离传输。为克服此缺点,并保持2PSK信号的优点,将2PSK体制改进为二进制差分
2、相移键控体制。二进制相移键控的基带信号是由相邻两码元相位的变化来表示的,它与载波相位无直接关系,因此在实际设备中,二进制相移键控得到了广泛的运用。课程设计介绍了话音信号的2DPSK调制系统,建立相关模型并对信号进行模拟调制和仿真。分析了信号源、差分器、调制和加噪模块的功能,最后用差分相干法和极性比较法对信号进行了调试。经调试后,信号源与抽样判决之后的信号,图形基本一致;不过前者调试后,信号波形有延迟,而后者没有。关键词:2PSK,2DPSK,调制系统27河南师范大学本科毕业论文AbstractModerncommunicationsystemsrequirecommunicationdist
3、ance,largecapacity,goodtransmissionqualityofcommunication.Asoneofthekeytechnologiesofmodulationtechnologyhasalwaysbeenoneoftheimportantresearchdirectiontopeople.Fromtheearliestfulfillmentofanalogmodulationfrequencymodulationtechnology,thedigitalmodulationtechniqueiswidelyusednow,makestheinformation
4、transmissionismoreeffectiveandreliable.Inbinarydigitalmodulation,whensinusoidalcarrierphasechangewithdiscretebinarydigitalbasebandsignal,areproducedbythebinaryphaseshiftkeying(2PSK)signal.Becauseintheprocessofmodulation,2PSKmodulationispronetoreversetheworkproblem,affectthe2PSKsignallongdistancetra
5、nsmission.Toovercomethisdrawback,andmaintaintheadvantagesof2PSKsignalwillbe2PSKsystemimprovementforbinarydifferentialphaseshiftkeyingsystem.Basebandsignalofbinaryphaseshiftkeyingissaidbychangesintheadjacenttwoyardsyuanphase,itandcarrierphasehasnodirectrelation,soinactualequipment,binaryphaseshiftke
6、yinghasbeenwidelyused.Paperintroducestherelativephaseshiftkeyingsignalmodulationprinciple,andestablishrelatedmodelforsimulatingthesignalmodulationandsimulation.Analyzingthesplitters,modulation,andpoorsignalsource,addnoisemodulefunctions,withdifferentialcoherentandpolaritycomparison,finallyhascarrie
7、donthedebuggingtosignal.Afterdebugging,thesignalsourceandthesamplingsignalaftertheverdict,basicallythesamegraphics;Buttheformer27河南师范大学本科毕业论文afterdebugging,signalwaveformwithadelay,whilethelatterisnot.Keywo