简介:摘要本文以幼儿为主角,将科技时代与幼儿教育相结合,借助二维码在平时生活中带来的便利,广泛运用,引发孩子们对二维码包含的数据、信息产生重重的思考与探索,激发幼儿的求知欲与好奇心,进而萌发“解密”二维码的兴趣。
简介:Amicroturbo-expandercapableofhighworkingspeedwasspeciallymanufacturedforuseinanorganicRankinecycle(ORC).Aseriesoftestswereexecutedtoexaminetheperformanceofthemachine.Intheexperiment,themachinewastestedunderdifferentinletpressureconditions(0.2-0.5MPa).Datasuchasthecompressedairpressure,temperaturesoftheinletandtheoutlet,rotationalspeed,andelectricpowergenerationwereanalyzedtodiscoverunderlyingrelationships.Duringthetest,therotationalspeedofthemachinereachedashighas54000r/min,thepeakvalueofthetemperaturedropbetweentheinletandtheoutletreached42℃,themaximumelectricpowergeneratedbythemotor-generatorattachedtothemachinereached630W,andtheefficiencyofthemachinereached0.43.
简介:ThemultilevelmodulationtechniquesofM-DifferentialAmplitudePhaseShiftKeying(DAPSK)havebeenproposedincombinationwithTurbocodeschemefordigitalradiobroadcastingbandsbelow30MHzradiochannel.ComparisonofthismodulationmethodwithchannelcodinginanAdditiveWhiteGaussianNoise(AWGN)andmulti-pathfadingchannelshasbeenpresented.TheanalysisprovidesaniterativedecodingoftheTurbocode.
简介:短波战术数据链在现代战争中发挥着重要作用.针对短波时变多径信道特性,提出了一种基于信道估计的Turbo均衡算法.该算法在初次迭代时根据训练序列的自相关特性,采用快速相关信道估计算法估计信道初始状态,并进行基于线性最小均方误差(MMSE)的Turbo均衡;然后利用译码器反馈的软信息,采用最小均方(LMS)迭代信道估计算法优化信道估计值,并进行迭代均衡.仿真结果表明,该算法的误码率性能逼近于假定信道状态已知的Turbo均衡算法,对Turbo均衡在数据链中实际应用具有借鉴意义.
简介:Space-TimeBlock(STB)codehasbeenaneffectivetransmitdiversitytechniqueforcombatingfadingduetoitsorthogonaldesign,simpledecodingandhighdiversitygains.Inthispaper,aunit-ratecomplexorthogonalSTBcodeformultipleantennasinTimeDivisionDuplex(TDD)modeisproposed.Meanwhile,TurboCoding(TC)isemployedtoimprovetheperformanceofproposedSTBcodefurtherbyutilizingitsgoodabilitytocombatthebursterroroffadingchannel.Comparedwithfull-diversitymultipleantennasSTBcodes,theproposedcodecanimplementunitrateandpartialdiversity;andithasmuchsmallercomputationalcomplexityunderthesamesystemthroughput.Moreover,theapplicationofTCcaneffectivelymakeupfortheperformancelossduetopartialdiversity.SimulationresultsshowthatontheconditionofsamesystemthroughputandconcatenationofTC,theproposedcodehaslowerBitErrorRate(BER)thanthosefull-diversitycodes.
简介:摘 要:针对传统LTE 1/3Turbo译码性能略低,并且经典的MAP Turbo译码算法由大量的乘除运算构成,计算复杂,资源消耗大,不利于FPGA的实现的问题。为了提高译码性能且方便工程实现及应用,采用1/5码率的Turbo译码,同时在经典MAP译码算法的基础上进行了一系列简化计算。最终在xilinx公司的xc7vx690tffg1157-2型号芯片上实现。