Path: utzoo!attcan!uunet!mailrus!uwm.edu!rpi!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!aplcen!haven!mimsy!fe2o3!michael From: michael@fe2o3.UUCP (Michael Katzmann) Newsgroups: sci.electronics Subject: Re: Composite Colour Signal (help my sanity) Keywords: NTSC Message-ID: <316@fe2o3.UUCP> Date: 21 Feb 90 16:23:46 GMT References: <507@ghp.UUCP> Reply-To: michael@fe2o3.UUCP (Michael Katzmann) Organization: Rusty's BSD machine at home Lines: 35 In article <507@ghp.UUCP> jim@ghp.UUCP (Jim Stewart) writes: >I have an old CGA that I am trying to get working with the composite >input to my colour TV. >It also works in black and white through the video input on the colour >TV (i.e., I display a game I know is in colour, but I only get grey >and white). I have looked at the composite output from the board. >I can see the colour burst, I can see the colour modulation, I think >I have the right levels, the colour burst frequency is in the right >range (pretty lousy accuracy from a scope). > >What are the critical details of NTSC with respect to colour? I can >post the parameters I measured if that helps. The colour burst frequency must be spot on! The receivers colour subcarrier oscillator must be able to lock on to it. The burst must be in the right position (5.3us after leading edge of sync). Also the level of the burst must be right or the set will operate the colour killer. (It should be abt 40 IRE units P-P (Whole signal is 140 units sync-tip to peak white + chroma). --------------------------------------------------------------------- email to UUCP: uunet!mimsy!{arinc,fe203}!vk2bea!michael _ _ _ _ Amateur | VK2BEA (Australia) ' ) ) ) / // Radio | G4NYV (United Kingdom) / / / o _. /_ __. _ // Stations| NV3Z (United States) / ' (_<_(__/ /_(_/|_