From: krk@griffith.janet.ucla.edu (Kenneth Kindsfater)
Newsgroups: rec.arts.anime
Subject: Re: HDTV
Date: 3 Sep 92 11:27:46 GMT
Organization: University of California at Los Angeles, EE Dept.

First let me start off by saying lets end this thread..... this
isn't the group for it, but I shall try to answer some questions
so it does come to an end....

In article <1992Sep1.201058.25673@ncsu.edu> jmkaraka@eos.ncsu.edu (JOHN MARTIN KARAKASH) writes:
>
>	An interesting note to the HDTV angle.  I was reading a science
>magazine (I think it was Scientific American) about a new way of
>compressing data.  It splits the data into two parts.  The first part is
>for broad, relatively static areas, at low resolution.  The second part
>is for all the detailed information.

This is correct but the reason it is split into parts is that they want
a graceful degradation of picture quality. When you broadcast digitally
with compression the picture will look great until you are at the edge of
reception then the picture quality will fall off rapidly. (in fact I heard
you might go from a ok picture to garbage but just crossing the street)
So anyways what they are doing is broadcasting to seperate signals the
low quality is broadcasted with higher power (so you can recieve it further
away)

Now you may ask why not broadcast just one signal of higher power... well
the problem is that HDTV must not intefere with NTSC television stations
that might be in other cities... What happens is that NTSC doesn't use the
whole bandwidth equally, so they sneak in the low quality high power signals
in the parts NTSC isn't using and use the lower power signal for the rest
of the bandwidth.

Anyways most of the proposal's are using digital QAM (quadrature amplitude
modulation) basically its what high speed computer modems use (>= 9600 baud)
(except most modem's do it with pure analog!!)

>	Now because of the FCC's (reasonable, I think) ruling that any HDTV
>transmissions also be viewable by standard sets, this would be the
>perfect technology to use.  One signal would give the old sets what they
>need, and the second signal would boost it up to HDTV standards.

This isn't what they are saying. They are saying that HDTV will use the same
frequencies as NTSC not that an old will be able display anything that an
HDTV station broadcasts. This will not be like the transition of b&w to
color, old sets will not be able to watch the new stations...

>	It has an amazingly high compression rate and works very well with
>digital information.

compression can be done using MPEG by (similar to JPEG but with motion
compenstation, i.e. taking the difference between the current and next
frame and transmitting that) Anyways though compression they have to
get it down to 24Mbaud rate which will be broadcasted...

>
>	-John 'Will we be *gasp* AHEAD of the Japanese?' Karakash-
As some one already pointed out the Japanese system (MUSE) is an
analog system odd's are that FCC will not pick it (it was submitted)
We may be ahead, but don't forget that when the FCC decides on a standard
Japanese will have a while to build sets before very many people buy
them (probably the first sets will cost more $20,000), so they will
probably 1-3 years before people really get around to buying new sets.

Let me point out finally that you might as well buy your LD's now since
what ever standard is adopted here, it will probably be different than
Japan so you won't be able to use their HDTV stuff anyways. Besides while
an NTSC set won't be able to watch an HDTV station, I'm pretty sure the
reverse will be true so I see no reason to put off buying an LD player
(especially for collecting anime) In fact I'll be buying a player soon I hope.

Oh ya one last thing I have seen a demonstration HDTV and the picture looked
great!!!

hoping my QAM chips end up in an HDTV,
ken