TV电视信号及协议讲解

AnBriefIntroductiontoTVVideosignalCyclistChenWorldwide3TVsystemsPALNTSCSECAM1.NTSC:NorthAmerica,Japan,SouthKoreaandTaiwan.2.SECAM:FormerCommunistblockcountries.3.PAL:Otherpartoftheworld.Distributionof3TVsystemsNTSCColorEncodingCompositeVideoHorizontalBlankingNTSCVideoActivelinesTheCompositeVideoWaveformYCSeparation•Themostfundamentaljobofavideodecoderistoseparatethecolorfromtheblackandwhiteinformationforvideocompositesignals.•CompositeSignalConstruction-LuminanceInformationfromDCto5.5MHz(B&WDetail)-ChrominanceInformationmodulatedontoacarrier(at3.58MHzor4.43MHz)-SynchronizationInformation(HorizontalandVerticalSync)YCSeparationS-VideoRGBequationRGBcolorpicturesarecreatedbyaddingthe3primarycolorstogether.Assumingwehave100%fullysaturatedR,GandBlevels,wewouldthenbeabletocreatethefully100%saturatedsecondarycolors;Cyan,MagentaandYellow.R,G,BcontributiontoLuminance•R,G,BcontributiontoLuminance:•Theadditionofcolorsinthecorrectproportioncreateswhite;unlikepaintwhichdarkens,e.g.,blackistheadditionofYellow,CyanandMagentapigments.•Forexample,inordertoproduceWhitelighttothehumanobserverthereneedstobe11%blue,30%redand59%green(=100%).•Y=0.299R'+0.587G'+0.114B'ColorEncoding:ColorBars•Y=0.30R'+0.59G'+0.11B'•R-Y=0.70R'-0.59G'-0.11B'•B-Y=-0.30R'-0.59G'+0.89B'ColorDeterminationVectorScopeColorDifferencePicturePerformance•Best:YPbPrColorDifferenceSignalinputs.•Good:S-Videosignalinput.•Common:CompositeVideo.(WhatsocalledAVterminals)•Why?Why?Whyneedtuner•Anelementofatelevisionsetthatallowstheusertoselectspecificsignalsandfrequencies(channels)tobeshownonthepicturetubeandplayedthroughthespeaker.•InTVstation,compositevideois“Modulated”,thencanbetransmittedintheairorcableforlongdistancetransmission.ModulationModulationF1F2F1+F2Demodulation•Tunerapplythedemodulationprocess;i.e.;returntheoriginalsignal--compositevideo.CameraInterlaceScanningPatternsCameraScanningPatterns•VerticalResolution–525horizontallinesperpicture.(NorthAmerica)–625horizontallinesperpicture.(Mostofworld)•VerticalScanRate–Scanatleast48timespersecondtoreduceflicker.–525or625linesat48timesperseconddifficulttoachieve.•InterlacedScan–Showalloddlinesonetime,allevenlinesnext.–Field–525-~60Fields–625-50Fields–Frame–525-~30Frames–625-25FramesTVreceiverVideoFormatsSummaryDigitalVideo--601SamplingY,Pb,PrQuantizingand4:2:2Y,Pb,PrQuantizingand4:2:2DVDPlayerProgressiveDecodingDifferenceBetweenY,Cb,CrandY,Pb,Pr•YCbCr:Digitalcolordifferencesignals.•YPbPr:Analogcolordifferencesignals.LCDTVBlockDiagramTT:256Kx8SRAMI2CL,RSC1StbyKeybL,RExternal,SC1,SC2TDA9875SoundTDA1517Y/Pb/PrCVBS-1IRPCA8521RC-5TransmitterSIFSAA55xxµC,TT,CCI2CSAA7118Y/C-1PCF85116EEPROMCVBSTXTI2CYPbPrDisplayControllerSAA6714VGAInterfaceDig.RGBTXT/CCITU656AnalogDVIInverterPowerLCD-PanelXGASXGARGBSDRAMXMx32I2CL,RExternalL,RSC2CVBSTunerFM1236MUXAnalog4W4WSCARTVideoin3DYCPictureBoosterRGBNTSCDemodulatorSourceDriverGateGhostCanceller