简介:阐述了雷达相关杂波的模拟方法及其AR谱模型的特性,提出了具有约束条件的修正LEVINSON算法及其AR模型阶数估计方法,同时给出了常用的高斯谱特性的模型阶数估计结果和仿真结果,并与同等条件下的BURG算法的估计结果进行了比较,得到了一些有价值的结论。由于修正LEVIN—SON算法是直接利用给定相关功率谱模型所得到的自相关函数进行AR谱估计的,避免了随机相位因子波动的影响,因此比BURG算法更逼近理想功率谱特性的估计结果。计算机仿真结果也证明,用AR模型来描述常用雷达相关杂波的功率谱特性是正确的;在合理的模型阶数下,AR模型谱的精度满足雷达相关杂波模拟的要求。
简介:ReactiveionetchingcharacteristicsofGaAs,GaSb,InPandInAsusingCl2/Arplasmahavebeeninvestigated,itisthat,etchingratesandetchingprofilesasfunctionsofetchingtime,gasflowratioandRFpower.Etchratesofabove0.45μm/rinand1.2μm/rinhavebeenobtainedinetchingofGaAsandGaSbrespectively,whileveryslowetchrates(<40nm/rin)wereobservedinetchingofIn-containingmaterials,whichwerelinearlyincreasedwiththeappliedRFpower.EtchedsurfaceshaveremainedsmoothoverawiderangeofplasmaconditionsintheetchingofGaAs,InPandInAs,however,werepartlyblackenedinetchingofGaSbduetoaroughappearance.
简介:AD73322是AD公司推出的一款低功耗双通道模拟前端器件。文章在介绍了AD73322的性能特点和TMS320C5402的结构特点的基础上.给出了一种利用TMS320C5402的多通道缓冲串行口(MCBSP)和AD73322AR组成数据采集模块的设计方案。
简介:ThepatternofITOtransparentelectrodeofpixelcellsinTFTAMLCDisacriticalstepinthemanufacturingprocessofflatpaneldisplaydevices,thedevelopmentofsuitableplasmareactiveionetchingisnecessarytoachievehighresolutiondisplay.InthisworkweinvestigatedtheAr/CF4plasmaetchingofITOasfunctionofdifferentparameters.WedemonstratedtheabilityofthisplasmatoetchITOandachievedanetchingrateofabout3.73nm/min,whichisexpectedtoincreaseforlongpumpingdownperiod,andalsothroughadditionofhydrogenintheplasma.FurthermorewedescribedtheITOetchingmechanisminAr/CF4plasma.Theinvestigationofselectivityshowedtobeverylowoversiliconnitrideandsilicondioxidebutveryhighoveraluminum.
简介:UsingTime-VaryingAR(TVAR)modelandadaptivenotchfilterisanewmethodforthenon-stationaryjammersuppressioninDirectSequenceSpreadSpectrum(DSSS).TheperformanceofTVARmodelforInstantaneousFrequency(IF)estimationwillbeaffectedbysomefactorssuchasbasisfunctions.Focusingonthisproblem,theoptimalbasisfunctionofTVARmodelfortheIFestimationoftheLFMsignalisobtainedinthispaper.Besidesthedepthandwidthofnotching,thephasepropertiesofnotchfilteraffecttheSignal-to-Interferenceplus-NoiseRatio(SINR)ofcorrelationoutputtothenarrowbandjammersuppressioninDSSS,inresponsetotheproblemtheclosedsolutionofcorrelationoutputSINRimprovementhasbeenderivedwhenasinglefrequencyjammerpassesthroughdirectIIRnotchfilter,anditsperformancehasbeencomparedwiththoseoffivecoefficientFIRfilters.Later,anovelmethodforLFMjammersuppressionbasedonFourierbasisTVARmodelanddirectIIRnotchfilterisproposed.Thesimulationresultsshowtheeffectivenessoftheproposedmethod.