简介:Inthisletter,weproposeahybridanalog/digitaldetectionalgorithm,theCorrelatedIn-terferenceCancellation(CIC)algorithm,forImpulseRadioUltra-WideBand(IR-UWB)system.TheCICalgorithmcorrelatesreceivedsignalwithitsdelayedversionsintheanalogdomainandsamplesthecorrelationoutputatthesymbolrate.Thesymbolratesamplesareprocessedinthedigitaldomaintoperforminterferencecancellation.Therefore,CICworksforhighdataratesystemswithheavyIn-terSymbolInterference(ISI).SimulationresultsshowthatCICachievesgoodperformanceintypicalUWBchannels.
简介:Duetolowparametersensitivityforbalancedrealizations,balancedstructurebecomesagoodcandidateforanstatespaceadaptiveinfiniteimpluseresponse(MR)filter.Here,usingcoefficientsofthetransferfunctionastheadaptivefilteringparameters,abalancedadaptiveIIRfilteringalgorithmisproposedforoutput-errorminimization.ThealgorithmintheinternallybalancedrealizationguaranteesthattheadaptiveIIRfilteralwaysminimizestheratioofmaximum-to-minimumeigenvalueoftheGrammianmatricesattheeachiteration.Simulationresultsareprovidedtocorroboratetheproposedalgorithm.
简介:UsingthesimpleinverseFouriertransformation(FT),theindexmodulationstructurewiththesampledperiodforthesampledfiberBragggratingswasdesigned.Inthismethod,theenablechannelsareoperatedatidenticalwavelengthwhiletheunablechannelsarealmostsuppressedcompletely.Theenableandunablechannelscanbeestablishedbasedontheapplications.Thistechniqueisveryusefultodesigntheopticaldevicessuchasopticaladdanddropmultiplexers(OADMs),andinterleaverswithdispersionanddispersionslopecompensation.
简介:AnewlygrownBaGa4Se7crystalhasbeensynthesizedviatheBridgman-Stockbargertechnique.Thisnewcrystalhasadvantagesofhighnonlinearoptics(NLO)coefficients,highlaserdamagethresholds,andwidetransparentregions.TheBaGa4Se7crystalhasbrightapplicationprospectsasanonlineargainmediuminmid-infraredandterahertzregions.Inthispaper,thecrystallinestructureandsyntheticmethodoftheBaGa4Se7crystalareintroduced.Therefractiveindicesandabsorptioncoefficientsalongthreedielectricaxesbetween0.1THzand1.0THzarealsoobtained.Theterahertzdifferencefrequencygeneration(THz-DFG)characteristicsbasedontheBaGa4Se7crystalinthefrequencyrangeof0.1THzto1.0THzareanalyzedtheoreticallyandthephase-matchingconditionsarecalculated.TheapplicationofBaGa4Se7crystalsinterahertzwavegenerationisalsodiscussed.
简介:WehaveUV-inscribedfiberBragggratings(FBGs),long-periodgratings(LPGs),andtiltedfibergratings(TFGs)intomid-IR2μmrangeusingthreecommonopticalfibergratingfabricationtechniques(two-beamholographic,phasemask,andpoint-by-point).ThefabricatedFBGshavebeenevaluatedforthermalandstrainresponse.IthasbeenrevealedthattheFBGdeviceswithresponsesinmid-IRrangearemuchmoresensitivetotemperaturethanthatinnear-IRrange.Toexploretheuniquecladdingmodecouplingfunction,wehaveinvestigatedthethermalandrefractiveindexsensitivitiesofLPGsandidentifiedthatthecoupledcladdingmodesinmid-IRrangearealsomuchmoresensitivetotemperatureandsurroundingmediumrefractiveindexchange.The45°tiltedfibergratings(45°-TFGs)aspolarizingdevicesinmid-IRhavebeeninvestigatedfortheirpolarizationextinctioncharacteristics.Asefficientreflectionfiltersandin-cavitypolarizers,themid-IRFBGsand45°-TFGshavebeenemployedinfiberlasercavitytorealizemulti-wavelength2μmTm-dopedCWandmodelockedfiberlasers,respectively.
简介:AmultisensordistributedextendedKalmanfilteringalgorithmispresentedfornonlinearsystem,inwhichthedynamicequationofthesystemandtheequationsofsensor’smeasurementsarelinearizedintheglobalestimateandglobalpredictionrespectivelyandthesuboptimalglobalestimatebasedonallavailableinformationcanbereconstructedfromtheestimatescomputedbylocalsensorsbasedsolelyontheirownlocalinformationandtransmittedtothedatafusioncenter.Ananalysisofthepropertiesofthealgorithmpresentedhereshowsthattheglobalestimatehashigherprecisionthanthelocaloneandsmallerlinearizationerrorthantheexistingmethod.Finally,anapplicationofthealgorithmtoradar/IRtrackingofamaneuveringtargetisillustrated.Simulationresultsshowtheeffectivenessofthealgorithm.
简介:Wavelengthmodulationtechnique(WMT)andactiveintracavitytechnique(ACIT)arefirstintroducedinthispaper,whichareusedtorealizetheconcentrationdetectionofmethaneandacetylenerespectively.WhenACITiscombinedwithwavelengthsweeptechnique(WST),thedetectionsensitivityofacetylenecanbeenhancedsharply.WhenACITiscombinedwithWSTandWMT,thedetectionsensitivityofacetylenecanbeenhancedfurther.
简介:Usingthehypothesisthatdatatransmittedbydifferentusersarestatisticallyindependentofeachother,thispaperproposesafixed-pointblindadaptivemultiuserdetectionalgorithmforTime-Hopping(TH)ImpulseRadio(IR)UltraWideBand(UWB)systemsinmultipathchannel,whichisbasedonIndependentComponentAnalysis(ICA)idea.Theproposedalgorithmemploysmaximizingnegentropycriteriontoseparatethedatapacketsofdifferentusers.Thentheusercharacteristicse-quencesareutilizedtoidentifythedatapacketorderofthedesireduser.Thisalgorithmonlyneedsthedesireduser’scharacteristicsequenceinsteadofchannelinformation,powerinformationandtime-hopingcodeofanyuser.Duetousinghypothesisofstatisticalindependenceamongusers,theproposedalgorithmhastheoutstandingBitErrorRate(BER)performanceandtheexcellentabilityofnear-farresistance.SimulationresultsdemonstratethatthisalgorithmhastheperformanceclosetothatofMaximum-Likelihood(ML)algorithmandisasuboptimumblindadaptivemultiuserdetectionalgorithmofexcellentnear-farresistanceandlowcomplexity.