简介:Anewmethodtoreducethenumericaldispersionofthethree-dimensionalAlternatingDi-rectionImplicitFinite-DifferenceTime-Domain(3-DADI-FDTD)methodisproposed.Firstly,thenumericalformulationsofthe3-DADI-FDTDmethodaremodifiedwiththeartificialanisotropy,andthenewnumericaldispersionrelationisderived.Secondly,therelativepermittivitytensoroftheartificialanisotropycanbeobtainedbytheAdaptiveGeneticAlgorithm(AGA).Inordertodemon-stratetheaccuracyandefficiencyofthisnewmethod,amonopoleantennaissimulatedasanexam-ple.Andthenumericalresultsandthecomputationalrequirementsoftheproposedmethodarecom-paredwiththoseoftheconventionalADI-FDTDmethodandthemeasureddata.Inadditionthere-ductionofthenumericaldispersionisinvestigatedastheobjectivefunctionoftheAGA.Itisfoundthatthisnewmethodisaccurateandefficientbychoosingproperobjectivefunction.
简介:Itisrevealedthatthedynamicstabilityof2-Drecursivecontinuous-discretesystemswithintervalparametersinvolvestheproblemofrobustHurwitz-Schurstabilityofbivariatepolynomialsfamily.ItisprovedthattheHurwitz-Schurstabilityofthedenominatorpolynomialsofthesystemsisnecessaryandsufficientfortheasymptoticstabilityofthe2-Dhybridsystems.The2-Dhybridtransformation,i.e.2-DLaplace-Ztransformation,hasbeenproposedtosolvethestabilityanalysisofthe2-Dcontinuous-discretesystems,togetthe2-Dhybridtransferfunctionsofthesystems.TheedgetestfortheHurwitz-Schurstabilityofintervalbivariatepolynomialsisintroduced.TheHurwitz-Schurstabilityoftheintervalfamilyof2-Dpolynomialscanbeguaranteedbythestabilityofitsfiniteedgepolynomialsofthefamily.Analgorithmaboutthestabilitytestofedgepolynomialsisgiven.
简介:IEEE802.16d通讯标准使用直角的频率部门multiplexing(OFDM)。在广泛地使用的OFDM系统,快Fourier变换(快速傅里叶变换)和反的快Fourier变换对被用来调制并且使解调副载波上的数据星座。在这份报纸,为OFDM调节的人和解调器的高效快速傅里叶变换的高级实现被介绍。设计在Verilog被编码了并且指向了可编程的门数组进XilinxSpartan3地。Radix-22算法被建议并且为OFDM通讯系统使用了。FFT的设计被实现并且适用于固定WiMAXIEEE802.16dcommuni-阳离子标准。结果被公布,硬件参数被比较。建议体系结构在使用的multipliers的数字是最少的,到在蝮蛇的数字的最少的存储器尺寸,和秒使用。