Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!udel!princeton!phoenix!gianulis
From: gianulis@phoenix.Princeton.EDU (Brad Gianulis)
Newsgroups: comp.sys.sgi
Subject: Re: Experiences with Video Framer/Video Creator ?
Keywords: video framer video creator
Message-ID: <8945@idunno.Princeton.EDU>
Date: 1 May 91 22:01:20 GMT
References: <1991Apr23.032930.5814@gpu.utcs.utoronto.ca> <8848@idunno.Princeton.EDU> <1991Apr29.203750.8792@eagle.lerc.nasa.gov>
Sender: news@idunno.Princeton.EDU
Organization: Princeton University
Lines: 51

In article <1991Apr29.203750.8792@eagle.lerc.nasa.gov> tttron@escher.lerc.nasa.gov (William Krauss) writes:
>In article <8848@idunno.Princeton.EDU> gianulis@phoenix.Princeton.EDU (Brad Gianulis) writes:
>>
>>We've been getting this "ghosting" or "echoing" or "looping"
>>or whatever you call it, where it looks like there is a duplication of the
>>video signal shifted to the right about 10 pixels and fainter. 
>
>This is a "hunch" but you might want to check the termination of your signal.
>
>>Brad Gianulis, Interactive Computer Graphics Lab
>>Princeton University
>
>
>
>-- 
>>>>> William D. Krauss			NASA Lewis Research Center  <<<<
>>>>> Graphics Visualization Lab		Cleveland, OH 44135    USA  <<<< 
>>>>> tttron@escher.lerc.nasa.gov(128.156.1.94)      (216) 433-8720  <<<<



Yes. That's the first thing we thought of, because we've seen this thing before
by using T-connectors to share the video signals coming from the CPU to the
monitor.

All our testing with the VC has been:

	CPU RGB output to VC

	VC RGB output to monitor

	VC NTSC output to composite video monitor

and that's it. 75 ohm terminations on both monitors.

I even tried disconnecting everything, except the SCSI connection and the
NTSC output, and sent an image to the frame buffer. No difference.

---------- NEWS FLASH -----------

Just in. The local SGI FE set up a VC in their office, saw the same "ghosting"
effects and said "that's as good as it gets", but they are going to try out yet
another VC box.


I just have the feeling that there is some poor engineering going on inside
the VC box regarding the video signals being brought in and being sent out.


- Brad Gianulis, ICGL
  Princeton U.