简介:Transmissionperformanceofelectroabsorptionmodulatorin10Gb/stransmissionsystemshasbeensimulatedandanalyzedundertheconditionoftakingintoaccountthechirp,extinctionratio,transmissivityandrise/falltime.ResultsshowthatshorttransmissiondistancewithoutEDFAafterEAMcanbeusedinfuturemetropolitanareanetwork,butthetransmissivitymustbecarefullyconsidered.Thesamplingtimerangeanddecisionlevelcanbeoptimizedtoreducethebiterrorratio.
简介:A10Gbit/srecirculatingsystemisconfiguredwithChirpedFiberBraggGrating(CFBG)forthedispersioncompensation.Forthefirsttime,thetransmissiondistanceintheloopreaches1000kmwithbiterrorrateof10-9.Theeffectofthegroupdelayrippleofthefibergratingisalsoinvestigatedintherecirculatingsystems,anditisshownthatthetransmissiondistanceislimitedto4cycles(4×167.1km)intheloopwiththepowerpenaltyfluctuationbelow1.0dB.Thusthegroupdelayrippleshouldbereducedtoallowforthewavelengthdriftof±5GHz.Attheendofthisletter,theprinciplesaregivenfordesigninglonghaulrecirculatingsystemswithdispersioncompensationCFBG.
简介:RFLDMOSs}/率管具有高输出功率、高增益、高线性、良好的热稳定性等优点,广泛应用于移动通信基站、数字广播电视发射以及射频通信领域、微波雷达系统。阻抗匹配是LDMOS~率管应用电路设计的关键任务,LDMOS功率管匹配电路的主要任务是实现功率管的最大功率传输。文中选择中国电子科技集团公司第58研究所研制的S波段10wLDMOS功率管,利用微波仿真工具ADS设计外匹配电路。经过精心调试后,s波段LDMOSs}/率管输入回波损耗、增益、输出功率、效率、谐波等技术指标达到设计要求。完成匹配电路设计的S波段LDMOS功率管在3.1~3.4GHz频率范围内,输出功率大于13.8W,功率增益大于12.4dB,效率大于37.9%。
简介:Digitalsignatureisoneofthemostimportantcryptographicprimitives.WeproposedanewdigitalsignatureschemebasedonCatalano’strapdoor.SinceCatalano’strapdoorismoreefficientthanexistingtrapdoorsinnumbertheory,ourschemeneednotmodularexponentiationbutseveralmodularmultiplicationsinthesigningalgorithm.Wealsoprovedourschemeisprovablysecureagainstadap-tivelychosenmessageattackbyusingtheForkinglemma.
简介:CRTCornercuttingtubeisconsideredasadefinitiverejectandwillbesenttoreclaimatalltimes.Itcausedlotsofmaterialloss.Inthispaper,anoveltechnologyusedtosaveCRTscornercuttingtubeispresentedfirstly.AsetofrepairsystemhasbeensuccessfullydevelopedtorepairCRTscornercuttingtube.Then,theprocesstechnologyforcornercuttingrepairhasbeenexcogitatedbyempiricalstudies.Finally,thecorrelativeperformancesofrepairedtubeareevaluated.Theexperimentalresultsshowthatthequalityofrepairedtubehasnodifferencewiththatofnormalproduct.Therepairyieldhasreachedabove97percent.Thisnewtechnologyhascontributedtoimprovingtheproductionyield,reducingthematerialconsumptionanddecreasingthecostofcolorCRTproduction.
简介:Thisletterintroducesthedesignideas,simulationandtestresultsofanS-bandklystronwithbandwidthof11%,whichwasdevelopedbytheInstituteofElectronics,ChineseAcademyofSciences(IECAS).Onthepeakpowerlevelof800kW,theefficiencyofklystronismorethan30%;thegainismorethan41dB;theequal-drivingrelativeinstantaneousbandwidthisover11%;theaveragepowerislargerthan8kW,andthepowerfluctuationwithinbandwidthislessthan1.5dB.
简介:ThecharacteristicofEDFAinWDMsystemisanalyzed.ThesimulationsystembasedonthearchitectureoftheChinaInformationNetwork(CAINONET)isintroduced,andtheinfluenceofnoisefigure,gainunflatnessandoutputpowerofEDFAontheBERperformanceandscaleofnetworkisinvestigated.Moreover,theinfluenceofnoisefigureisstudiedwithdifferentcrosstalk.Meanwhile,itisindicatedthatitisimportanttoapplythe"nodeisolationprinciple"intheopticalnetwork.Theresearchresultscanprovidethevaluablereferenceforthepracticalconstructionofallopticalnetwork.
简介:ThislettergivesarandomconstructionforLowDensityParityCheck(LDPC)codes,whichusesaniterativealgorithmtoavoidshortcyclesintheTannergraph.TheconstructionmethodhasgreatflexiblechoiceinLDPCcode'sparametersincludingcodelength,coderate,theleastgirthofthegraph,theweightofcolumnandrowintheparitycheckmatrix.ThemethodcanbeappliedtotheirregularLDPCcodesandstrictregularLDPCcodes.Systemiccodeshavemanyapplicationsindigitalcommunication,sothisletterproposesaconstructionofthegeneratormatrixofsystemicLDPCcodesfromtheparitycheckmatrix.Simulationsshowthatthemethodperformswellwithiterativedecoding.
简介:ItiswellknownthatthealgebraicexpressionofASSS-boxisverysimpleandonly9termsareinvolved.Hence,AESsecurityissuspectedalthoughthereisnovulnerabilityonitsofar.ToeliminatetheweaknessofextremelysmalltermsinthealgebraicexpressionofAESS-box,oneimprovedAESS-boxisproposed,whichpreservesthealgebraicdegreeinvariablebutsignificantlyincreasesthenumberofitsalgebraicexpressiontermsfrom9to255.Atthesametime,Booleanfunctionhasgoodcharactersinbalanceandstrictavalanchecriterion(SAC),etc.Finally,itisprovedthattheimprovedAESS-boxschemeissecuregainstthepowerfulknowndifferentialandlinearcryptanalysis.