简介:基于AlGaN/GaNHEMT工艺制作了大栅宽GaN高电子迁移率晶体管(HEMT)管芯,通过负载牵引及建模技术提取了管芯的输入阻抗、输出阻抗。设计中首先通过L-C网络提升了管芯的输入阻抗、输出阻抗,并通过微带多节阻抗变换器实现了宽带功率分配器及合成器电路的制作,同时还加入了稳定网络,最终实现了50Ω输入输出阻抗匹配。该大功率GaNHEMT内匹配器件采用四胞管芯功率合成技术,总栅宽为4×16mm。在50V漏电压、1ms周期、10%占空比的测试条件下及5.3~5.9GHz频率范围内,输出功率均高于56dBm,最高达到56.5dBm,功率增益均大于12dB,带内功率附加效率超过48.2%。
简介:Alow-lossfiberopticrotaryjoint(FORJ)hasbeendesignedbyusingtwokindsofC-lenscollimators.Itsinsertionlossandinsertionlossvariationduetorotationwithsingle-modefibercollimatorislessthan1.76dBand0.43dBrespectively.Themaximuminsertionlossandcouplingvariationduetorotationwithmulti-modefibercollimatoris1.71dBand0.29dB,respectively.ThiskindofFORJfeatureslowinsertionloss,smallcouplingvariationduetorotationandlowcost.
简介:Thetracking,telemetryandcommand(TT&C)missionisextremelyreliableforitscharactersofsmalltimehorizonandhighredundancy.Thecombinedforcingandfailurebiasing(CFFB)methodthatisusuallyusedforsimulatingtheunreliabilityofthehighlydependablemissionsystemseemsnotsoefficientfortheTT&Cmission.TheconceptabouttheimportanceoffailuretransitionisproposedbasedonthelogicalrelationshipbetweenTT&Cmissionanditsinvolvedresources.Then,theimportanceisusedforreadjustingthetransitionrateofthefailuretransitionwhenusingtheforcingandfailurebiasingduringthesimulation.ExamplesshowthattheimprovedCFFBmethodcanevidentlyincreasetheoccurrenceoftheTT&Cmissionfailureeventanddecreasethesamplevariance.MoreredundancyoftheTT&CmissionleadstotheimprovedCFFBmethodmoreefficient.
简介:Modelingandreasoningondomaincontextsplayakeyroleforaddingintelligencetocommunicationservices,andtheapproachofcapability-basedrequirementengineeringensuresthescientificityandaccuracyofrequirementelicitation.Thispaperpresentsacapability-basedcontextontologymodelingapproachforcommandandcontrol,communication,computer,intelligence,surveillanceandreconnaissance(C4ISR)communication.Primarily,acapability-basedC~4ISRcommunicationmeta-conceptmodelandaC~4ISRcommunicationcontextmeta-ontologyareconstructed.ThecontextontologyisestablishedundertheconstraintsoftheC~4ISRcommunicationcontextmeta-ontology,andfurthermore,algorithmsareproposedtosupportcontextreasoningbasedondescriptionlogic.Acasestudyispresentedtodemonstrateapplicabilityoftheproposedmethod.
简介:TLC320AD50C作为一款语音处理芯片有着广泛的应用。文章介绍了TMS320VC5402的多通道缓冲串口(McBSPs)与音频芯片TLC320AD50C的硬件连接的设计与实现。介绍了TMS320VC5402的多通道缓;中串口和音频芯片TLC320AD50C的工作原理和初始化的方法,以及典型应用中的TMS320VC5402对TLC320AD50C控制方式和TLC320AD50C采样频率的设定。最后给出了该系统的初始化程序,并实现了在硬件系统上的运行。
简介:TheionospherictimedelayisoneofthemainerrorsourcesinC/AcodeGPSnavigationandpositioningapplications.Inthispaper,amethodisproposedforreal-timedual-frequencyionospherictime-delaycorrectingusingaC/AcodeGPSreceiver,andtheprincipleofthecircuitblockdiagramforthismethodisanalyzedwithitsfeasibilitytheoreticallydemonstrated.