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- Path: sparky!uunet!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!ucbvax!mtxinu!taniwha!paul
- From: paul@taniwha.UUCP (Paul Campbell)
- Newsgroups: comp.sys.mac.hardware
- Subject: Re: info on NTSC out boards/boxes?
- Keywords: video NTSC rosebud
- Message-ID: <1148@taniwha.UUCP>
- Date: 10 Aug 92 17:41:06 GMT
- References: <1992Aug7.211649.16297@tamsun.tamu.edu>
- Organization: Taniwha Systems Design
- Lines: 50
-
- In article <1992Aug7.211649.16297@tamsun.tamu.edu> jdhaney@benthos.tamu.edu writes:
- >
- >we are making videos using MacroMind Director, a Computer Video NTSC
- >encoder box hooked to an Apple 8.24GC card in a IIfx.
- >but we are not satisfied with the quality of picture we are getting.
- >almost all the colors are ghosting quite a bit - the reds of course
- >being the worst. (a red circle shows as two distict circles side by
- >side, one orange)
-
- Ghosting in video systems is usually caused by reflections in the video cables
- somewhere - like SCSI cables - video cables must be properly terminated -
- usually this is done internally in the monitor (or the thing you have at the
- other end of the cable) - this is often visible when you go to a trade show
- and someone has slaved 2 big monitors of the same CPU by using BNC T connectors
- without removing the terminators from the middle monitor.
-
- From what you say it sounds like you have a setup like:
-
-
- --------- --------- ---------
- | | | | | |
- | CPU |---------------|encoder|---------------|display|
- | | | | | |
- --------- --------- ---------
-
- The connsction between the CPU and the encoder is RGB video, and between the
- encoder and display is NTSC video.
-
- If you only have a problem with red then the problem is either something wrong
- with the encoder (in which case you have to replace it) or something wrong
- with the cable between the CPU and the encoder - this last one is more likely,
- it sounds like the red channel only has a problem - the best things to look for
- here are:
-
- - make sure that you are using a high quality cable, is it damaged?
- - are both ends of the cable connected correctly?
- - is this cable too long?
- - is there a connector in the middle of this cable (if true this is
- a likely cause of your problem - all connectors in cables cause
- impedance mismatches and reflections)?
- - is the encoder correctly terminated?
-
-
- Paul Campbell
- SuperMac
- --
- Paul Campbell UUCP: ..!mtxinu!taniwha!paul AppleLink: CAMPBELL.P
-
- "'Potato', not 'Potatoe'"
- Bart Simpson - on the blackboard 6/25/92
-