基于VHDL语言的HDB3码的编码和译码

I摘要伴随着集成电路技术的发展，电子设计自动化(EDA)逐渐成为重要的设计手段，已经广泛应用于模拟与数字电路系统等许多领域。EDA的一个重要特征就是使用硬件描述语言(VHDL)来完成设计文件。诞生于1982年的VHDL语言是经IEEE确认的标准硬件描述语言，在电子设计领域受到了广泛的接受。数字基带信号的要求主要有两点，第一是对各种代码的要求，期望将原始信息符号编制成适合于传输用的码型；第二则是对所选的码型的波形的要求，期望波形适宜于在信道中传输。HDB3编码是数字基带信号传输中常用的传输码型，因其具有无直流成分，低频成分少和连零位数目最多不超过三个等明显的优点，对时钟信号的恢复十分有利而成为普遍使用的基带传输码之一。本设计是在QuartusII开发环境下采用VHDL语言的，设计HDB3编码器和译码器。根据编码规则将译码器分为三个部分：插V模块、插B模块、单极性变双极性模块。根据译码规则，译码器只包含一个模块。最后，对每个模块进行仿真，实现相应功能后再进行整体仿真。关键词HDB3VHDL编码译码IIAbstractTheElectronicDesignAutomation(EDA)technologyhasbecomeanimportantdesignmethodofanaloganddigitalcircuitsystemgrowing.OneimportantcharacteristicoftheEDAAsistheintegratedcircuitoneofthestandarddescriptionlanguagesvalidatedbyIEEE，whichwasfirstlyintroducedin1982.Anditwaswidelyusedbyelectronicdesignernow.Therequirementsofdigitalbasebandsignalsaretwopoints,Thefirstistherequirementofvariouscode,expectedthepreparationoftheoriginalinformationsymbolsusedtopatterninaformsuitablefortransmission;Thesecondistherequirementsofthepatternoftheselectedwaveform,expectedwaveformsuitablefortransmissioninthechannel.TheHDB3codingschemeiscommonlyusedindigitalbasebandtransmission.TheHDB3code，whichhasfeaturesofzeroDCbiasviaalternatingpositive-negativevoltagelevelbitbybitandnomorethanthreecontinuous-zerobits，deducesthepowerdissipationandmakesthereceivingdeviceeasytorecovertheclockinthetransmittedcodestream.somymajorcontentofgraduateddesignisdesigningbasedontheHDB3volume/decoderofVHDLlanguage，therequirementthatitwillreachisthebasicskillthatcanrealizeHDB3volume/decoderfunctioninsoftwarecan，andcancoordinateentiredesign，makesureitreachtherequirementthatanticipated.ThisdesigninQuartusIIdevelopmentenvironmentusesVHDLlanguagetodesignHDB3encoderanddecoder.Accordingtotheencodingrules,therearethreepartsindecoder:insertthemoduleV,insertthemoduleB,theunipolarvariablebipolarmodule..Accordingtothedecodingrules,decodercontainsonlyonemodule.Finally,thesimulationofeachmodule,itachievethecorrespondingfunctionandthenachievethewholesimulation.KeywordsVHDLHDB3EncodingDecodingIII目录摘要......................................................................................................................IAbstract.......................................................................................................................II第1章绪论.............................................................................................................11.1研究目的和意义..............................................................................................11.2基带传输码型简介..........................................................................................21.2.1AMI码.................................................................................................21.2.2数字双相码.........................................................................................21.2.3NRZ码.................................................................................................31.3VHDL语言简介...............................................................................................31.3.1VHDL定义..........................................................................................31.3.2功能和特征.........................................................................................41.3.3应用优点.............................................................................................41.4QuartusⅡ简介...................................................................................................41.4.1QuartusII的产生与发展....................................................................41.5本设计的研究内容..........................................................................................6第2章HDB3码的编/译码的规则........................................................................72.1HDB3码简介....................................................................................................72.1.1HDB3码定义......................................................................................72.1.2HDB3码特点......................................................................................72.2HDB3码编解码器的国内外发展情况............................................................82.3HDB3码的应用................................................................................................92.3.1HDB3码测井电缆遥传系统中的应用..............................................92.3.2HDB3码高速长距离通信..................................................................92.3.3HDB3码在基带数据传输中的应用................................................102.4HDB3码的编码规则......................................................................................102.5HDB3码的译码规则......................................................................................102.6本章小结........................................................................................................11第3章HDB3码编码器的建模与实现...............................................................12IV3.1插V模块的建模与实现...............................................................................123.1.1设计思路..................................................................