[opendtv] Re: PAL

  • From: flyback1 <flyback1@xxxxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Fri, 15 Dec 2006 15:22:44 -0500

John Shutt wrote:

I thought the NTSC cure to green people was VIRS. Gee, whatever happened to all those television sets out there using VIRS? The FCC mandated that if we transmit anything on line 19 of NTSC, it had to be the GCR signal. This displaced the voluntary VIRS that many professional Proc Amps and at least one consumer television set, RCA, used to automatically set chroma phase and amplitude. VIRS got moved to differing lines, and most professional equipment using VIRS could be reprogrammed to find it, but those consumer TV sets were out of luck.

I guess right about the time that the technology got cheap enough to enable something like VIRS, the rest of the technology got stable enough to not require it anymore. Not that GCR was a roaring success, either.


The VIRS signal worked very well except for one problem; some TV stations mistakenly deleted the whole vertical blanking interval including the VIRS
in the incoming network proc. amp and reinserted their own VITS and VIRS.

Any distortion in the network signal the original VIRS could have corrected in consumer TVs got through anyway.

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