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1、西北工業(yè)大學(xué)碩士學(xué)位論文水聲通信編碼與同步技術(shù)研究姓名:王平申請(qǐng)學(xué)位級(jí)別:碩士專(zhuān)業(yè):通信與信息系統(tǒng)指導(dǎo)教師:張效民20030301AbstractInthepast10years,therapiddevelopmenthashappenedinthestudyofunderwateracoustic(UWA)communicationtechniques,withmoreattentiontotheunderwateracousticcommunicationsystems.Thedissertationbeg
2、inswiththeintroductionoftheunderwateracousticcommunicationsystem,andiscompactlydevotedtothestudyonthesynchronizationandcodingtechniquesinunderwateracousticcommunication,basedontheanalysisofthecharacteristicsofUWAchannels.ThethreemaincharacteristicsofUWAchann
3、elsarestudiedthoroughly,andtheirinfluenceontheUWAcommunicationsystemarecompletelyanalyzed.AimedatthefeaturesoftheUWA,theLFM(1inearfrequency—modulated)pulsesynchronizationisproposed,inwhichLFMistheframesynchronizationsignal,andrealizeaccuratesynchronizationby
4、usingreplicacorrelationinreceivingend.TheLFMpulsetimedelaycodingmethodisalsoproposedindissertation,whichincreasesthespeedoftransmittingsignalinUWA.TheUWAmodulatorytechniquebasedonFrequencyShiftKeying(FSK)issystematicallyandin—depthstudied.AssociatedwiththeLF
5、Mflamesynchronizationmethod,thethreemethods:periodogrammethod,Welch’Smethodandhigher-ordercumulantmethodarecompletedanalyzed.IncombinationwiththecharacteristicsofUWA,DifferentialPhaseShiftKeying(DPSK)isstudied.Thetwodemodulationmethods:differentialdemodulati
6、onmethodandcrossspectrademodulationmethodaredeeplystudied.WiththeLFMpulseframesynchronizationmethod,theperformanceofUWAcommunicationsystembasedonDPSKisapparentlyimproved.Keywords:UnderwaterAcousticDigitalCommunicationUnderwaterAcousticchannelFrameSynchroniza
7、tionLinearFrequencyModulated(LFM)PulseTimeDelayCodingFrequencyShiftKeying(FSK)DifferentialPhaseShiftKeying(DPSK)2墮!!三些查蘭堡!蘭笪笙苧——————————————————————.!絲序言第一章緒論近幾年來(lái),隨著海洋開(kāi)發(fā)事業(yè)的發(fā)展,各種數(shù)據(jù)信息,如遙測(cè)數(shù)據(jù)、水下機(jī)器人和海上石油平臺(tái)的遙控?cái)?shù)據(jù)、水文站的采集數(shù)據(jù)等等,對(duì)利用水聲信道和水聲通信系統(tǒng)進(jìn)行傳送的要求大為增加。水聲通信應(yīng)用范圍的增大使得對(duì)系
8、統(tǒng)的信息量和性能的要求也隨之增加,國(guó)內(nèi)外已經(jīng)開(kāi)展了大量的工作著重研究怎樣擴(kuò)展系統(tǒng)的帶寬和如何提高數(shù)據(jù)的傳輸率上,這些研究主要集中在編碼調(diào)制技術(shù)和抑制多徑干擾的信號(hào)處理方面。本文正是在這樣的情況下,結(jié)合國(guó)防十五重點(diǎn)預(yù)研課題“水聲遙控技術(shù)”而提出的。1.1水聲信道和水聲通信技術(shù)簡(jiǎn)介海水介質(zhì)是一種導(dǎo)電介質(zhì),向海洋空間輻射電磁波會(huì)被海水介質(zhì)本身所屏蔽,其大部分能量會(huì)以渦流的形式被損耗掉,因此電