电视演变及新一代电视(IJMECS-V4-N4-7)

I.J.ModernEducationandComputerScience,2012,4,50-56PublishedOnlineMay2012inMECS()DOI:10.5815/ijmecs.2012.04.07EvolutionandFutureGenerationofTVSandeepJoshiDepartmentofElectronics&CommunicationEngineering,ShivNadarUniversity,UttarPradesh,IndiaEmail:[e-mail]complex,1,KailashGhoshroadBlock-G,Flat-2W,Kolkata,Pin700008,IndiaEmail:[e-mail]—NootherelectronicmediahascreatedasmuchmassimpactastheTV.TVisbothapersonalaswellasfamily/communitydevicewhichmakesitreachalargepopulation.ObviouslytheimmensepopularityofTVhasresultedinanunprecedentedgrowthofTVviewingaswellastechnology.FromthesimpleTVtodayonecanhaveasmartTVwithvaryingfeaturessatisfyingallsectionsofsociety.TheTVtechnologyhasgrowninallaspectsnamelytheTVstudiotechnology,theTVtransmitter&broadcasttechnologyandtheTVreceivingdevicetechnology.NotonlyhavetheTVsignalsbeenconvertedfromanalogtodigital,todayonehashighdefinitionTV,theIPTV,themobileTVandthe3DTVcommerciallyavailable.ItisveryinterestingandimportanttotracetheevolutionofTVtechnologyfromitsbasicformasin1930stodateandtovisualizetheirtechnicalfeaturesatvariousstagesofdevelopments.ThispapergivesanoverviewofthedevelopmentsinTVtechnologyhighlightingtheirimportantfeatures.IndexTerms—IPTV;MPEG;Compression;MobileTV;DigitalTVI.INTRODUCTIONTVhasbecomeaverypopularandcommonhouseholditemworldover.Itscapabilityofprovidingentertainment,news,variousotherusefulinformationsuchasweather,political,scientific,agricultural,disasters,currentdevelopments,etc.,videogaming,lessonsineducation,healthcareguidance&travelandtourismdetailstopeoplesittingattheirhomeatreasonablyaffordablecosthavemadeitverypopular.Allthesecapabilitiesaretheresultofresearchandtheadvancesintechnologyinmanyfields.Inarelativelyshortperiodoflessthanthreequartersofacentury,theTVcanberegardedasoneofthemarvelousinventions.Combinedwiththecomputer,internetandwebtechnologies,TVtodayisbecominganexcellentexampleofconvergenceofcommunication,computersandbroadcasting.Itofferstodaywebbrowsing,interactivecommunicationandsocialnetworking.Technicallytheinformationcontentofvideosignalsisveryhigh(thousandtimesthevoiceinformation)andassuchitstransmissionandbroadcastingbyconventionalmeanswouldrequireaveryhighbandwidthwhichwouldbepracticallyimpossible.Theadvancesincoding,compressionandsignalprocessingtechniqueshavemadethelowbandwidthvideopossible.ThishasfurtherresultedinmakingalargenumberofTVchannelsandprogramsavailableinalimitedRFspectrum.InthispapertheevolutionofTVhasbeenpresentedwithimportantfeatures.Thenextsectiondescribestheevolutionofanalog,digitalandtheHDTV.ThethirdsectioncontainsthefeaturesoffuturegenerationTVsuchasIPTV,3DTV,MobileTVandsmartTV.ThelastsectiongivesabriefconclusiononprogressofTV.II.EVOLUTIONOFTVA.AnalogTVTelevisionimpliesviewingmotionfarfromtheobserverthatistoseeatadistance.Itisamethodoftransmittingandreceivingascenewhichisinmotionasseenbyhumaneyeandheardbyhumanear,withthehelpofradiobroadcastingortransmissioncable.Motionpicturereproducesstillpictureintheformofasnapshot.Ifthesesnapshotsareshownoneaftertheotherinafastsequencetheygiveanillusiontohumaneyethatitisamovingpicture.Thereforetelevisionshouldbeabletotransmitandreceiveastillpicture.FortransmissionandreceptionofvisualinformationthatispicturethesystemshouldhaveacameratubeandanimagereproducingtubecalledasTVsystem.ThefamouscameratubesusedareOrthiconTube–basedonphotoelectronemissionandVidicontube-basedonphotoconductivity[1],[2].Eachimageisdividedintosmallelementscalledimageelement,pictureelement,pelorpixel.ToviewtheimageithastobereadpointbypointwhichiscalledasScanning.Itistheprocessrequiredfortransmissionofpicturewhichisdividedintohorizontallinescalledraster,elementbyelement.Itisdonebyanelectronbeam,whichscanshorizontallyaswellasvertically.Interlacedhorizontalscanningdividestotalnumberoflinesintheframeintotwoparts.Incountrieswherethefrequencyoftransmissionis60Hzframerateis30framespersecondCopyright©2012MECSI.J.ModernEducationandComputerScience,2012,4,50-56EvolutionandFutureGenerationofTV51andwherethefrequencyis50Hzthentheframerateis25framespersecond.TVresolutioncanbedescribed[3]measuredandspecifiedindifferentways•Numberoflinesper(mmorinch)bothhorizontallyandvertically.•Numberoflinepairsper(mmorinch)verticallyandhorizontally.•Numberoflinespertotaldisplay-Linesperpictureheight(LPH)TABLEI.SUMMARYOFANALOGTVSTANDARDSStandardNumberoflinesVideoB.W.(MHz)Frequencybands(MHz)ChannelB.W(MHz)SoundmodulationCCIRB,G625547-68,174-230&470-8537or8FMOIRTD625648.5-100,174-2308FMFrenchVHFE81910.650-70,160-21513.15AMFCCUSAM5254.254-88,174-266,470-8906FMColorhelpshumaneyetoperceivetheinformationbetterandextracttheinformationfromthescene,thismotivationledtocolorTVdesign.TocompressacolorimagethetransformationtotheRGBrepresentationofimageisamoreeffectivecompressionmethod.Primarycolorsarered,blueandgreen,theyaresentinindependentcombinationdenotedasEYLuminancesignalandEI,EQcalledchrominancesignalsorcolordifferencesignals.ForTVtransmissionVestigialSideBand(VS