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:ThispaperpresentsapragmaticadaptiveschemeforTuCMoverslowlyfadingchannels.Theadaptiveschemeemploysasingleturbocodedmodulatorcomposedofavariable-rateturboencoderandavariable-ratevariable-powerMQAMforallfadingregions,soithasanacceptablecomplexitytoimplement.TheoptimaladaptiveTuCMschemeisdeterminedsubjecttovarioussystemconstraints.Simulationshavebeenperformedtomeasuretheperformanceoftheschemefordifferentparameters.Itisshownthatadoptingboththeturbocodedmodulatorandthetransmitpowerachievesaperformancewithin2.5dBofthefadingchannelcapacity.
简介:Researchontheflowfieldinsideaturboclassifieriscomplicatedthoughimportant.Accordingtothestochastictrajectorymodelofparticlesingas-solidtwo-phaseflow,andadoptingthePHOENICScode,numericalsimulationiscarriedoutontheflowfield,includingparticletrajectory,intheinnercavityofaturboclassifier,usingbothstraightandbackwardcrookedelbowblades.Computationresultsshowthatwhenthebackwardcrookedelbowbladesareused,themixedstreamthatpassesthroughthetwobladesproducesavortexinthepositivedirectionwhichcounteractstheattachedvortexintheoppositedirectionduetothehigh-speedturborotation,makingtheflowsteadier,thusimprovingboththegradeefficiencyandprecisionoftheturboclassifier.Thisresearchprovidespositivetheoreticalevidencesfordesigningsub-micronparticleclassifierswithhighefficiencyandaccuracy.
简介:有入口翼的涡轮blowers的最佳的操作被学习了理解操作性能的blowers。为了连续地在涡轮blowers分析三维的流动地,连接的、一般分析代码,CFX,在现在的工作被介绍。SST骚乱模型被雇用估计旋涡粘性。在整个数字分析,涡轮blowers的流动率能在在90之间的翼角度(全部的公开条件)被控制,这被发现度和60度有效地,因为压力损失很快在一个翼角度的60度下面增加。效率也几乎从90度有一样的价值到一个翼角度的60度。在小翼角度产生的弄歪的入口速度由于本地前缘分离和装载的下列不一致的片使性能成为涡轮blowers的恶化,这被注意。