[opendtv] Re: Digital vs. Analog Quality

  • From: Cliff Benham <flyback1@xxxxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Sun, 13 Jul 2008 21:58:27 -0400

Dale Kelly wrote:
Can I assume that all DTV sets with NTSC tuners now have full NTSC chroma
bandwidth? If so, that's only about 50 years too late.....

It's a hard question to answer since all the new sets and displays with NTSC composite and S-video inputs don't bother to say what their chroma bandwidths are in the specs I've downloaded.

I think you will have to check them out one by one with good test gear to know for certain.

As for wide Y and C bandwidth sets being 50 years too late I think that any such TVs from the '50s through the early '70s would probably not have improved the resolution of the images at home.

It was the act of decimating the RGB signal with an NTSC broadcast encoder that for most sets, limited it's resolution to ~40 lines for C and ~320 for Y.

In the late 1940s there were several proposals before the FCC to transmit color only in the new UHF band with channel bandwidths of from 12 to 18 megacycles (!) None were ever approved for commercial use.

Broadcast NTSC was the sole signal source of programming during those decades, and even if your set was a Conrac or RCA studio monitor, you would not have seen much improvement in either Y or C resolution.

It's only since the advent of Laserdisks, S-video, DVDs and digital TV receivers that it's possible to watch higher chroma resolution images.

It's also hard to know if the new sets are using good I&Q decoders, wideband R-Y&B-Y decoders or ??? for NTSC because the manufacturers don't include such information in their specs.

I guess they want to emphasize only the 'digital' aspects of their new products or perhaps at least widen the percieved quality differences between the analog and digital images.

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