[opendtv] Re: Digital vs. Analog Quality

  • From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Fri, 11 Jul 2008 17:19:44 -0400

Craig Birkmaier wrote:

> The discussion was about how much information can be carried
> by a baseband composite video signal.
> Please do not try to pull a "Bert" on us and justify your
> position by changing the subject.

This is your standard reply when you are unable to follow a thread. A
common problem among those who prefer to transmit than to receive, which
was oh so painfully obvious in this thread too.

If you go back to the references Cliff posted on 7 July, you will see
what his point is.

The references state that the color resolution of NTSC composite
interfaces is limited to about 120 lines in practice, and 140
theoretical. HOWEVER, the color broadcast in OTA NTSC transmissions is
much less than that. Here's the quote:

"NTSC Broadcasts (composite) - 120 lines best, 40 - 48 lines typical for
reddish orange and greenish blue; 40 - 48 lines for most other color

So, what was this all about? It was about explaining that if you use a
CECB to decode a TV signal, as opposed to watching the NTSC broadcast,
over the composite interface, you should notice much better color
resolution than from the NTSC broadcast. Because the CECB creates the
composite signal from the 4:2:0 digital, and is not limited to the ~40
lines in practical NTSC broadcasting. It is ONLY limited to the 120
lines of NTSC at its practical best.


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