Published by: Larry Bloomfield & Jim Mendrala
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Larry Bloomfield & Jim Mendrala
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Tech Note - 012
experiences, knowledge or anything else relating to DTV, HDTV etc.
with your fellow engineers is what we are all about. We've
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Subj: Wide Screen, Big Screen and HDTV
From: James Mendrala)
In the coming
months we are going to see what the TV set manufacturers are
going to have
to receive the new DTV. While we are waiting let me say a few
the differences between Wide Screen, Big Screen and HDTV.
today has an aspect ratio of 4x3. From the NTSC transmitter
we are able
to receive an image of around 480x360 pixels. Because of the
of the eye, as long as that image is viewed with a horizontal
of less than eight degrees the viewer will see a high
on that screen. Now this viewing angle is not very wide
but fits nicely
into the average living room with a 27 inch diagonal
display. If we now implement the new DTV with its 702 pixel
we will be able to transmit the same images with a higher
The vertical resolution would still be around 360 as
it would remain the same.
In an article
by Frank Becham in the TV Technology (Vol. 15 No. 22 Pg. 8),
Thorpe explained that as long as the amount of spectral energy
detail) in the scene does not exceed the limits of the
system, standard definition will look about the same
as a high definition.
This means that if you are viewing an image from an
SDTV DTV transmitter
with a 27 inch diagonal screen at a viewing distance
of 17 feet you
would have a viewing angle of about 8 degrees. A high
would look similar to that of an SDTV image on that
from the same distance. If the SDTV image was blown up or
a 32 degree viewing angle, it would look soft.
is related to bandwidth, or as Larry Thorpe likes to say,
A lot of manufacturers already know that their video
close-ups of people, flowers, animals, etc.) are quite
These images contain less spectral energy and lower bandwidth
and less detail.
We've all seen this at TV trade shows regularly.
We know the
number of scan lines in NTSC and SDTV are fixed at 525 lines
and by definition
cannot be changed. So we are stuck with 360 vertical
lines minus vertical blanking and other non picture lines,
times the Kell
If you have
a 27-inch diagonal display that can resolve 480 horizontal
would have to be about 13 ft. from the screen to view a NTSC
image, as transmitted,
in high resolution. This is a viewing angle of about
If the 27-inch
display could resolve 720 horizontal pixels, one and a half
times the resolution
of NTSC, DTV then would move you up to a viewing
about 8.5 ft. This is a viewing angle of about 12 degrees. But
the same number
of scan lines in the 4x3 image would mean the vertical
be less than the horizontal resolution. This is not good
image should have equal vertical and horizontal resolution. By
a wide screen image we now have equal horizontal and vertical
If the 27 inch
display could display 1920 horizontal pixels (five times the
NTSC), DTV then would move you up to about 3 ft. from the
is a viewing angle of about 32 degrees.
Now if all of the above images were viewed
at the same distance of 13 ft.
then all would
have a viewing angle of 8 degrees. All images would look
similar at that
distance. Reason? The eye (for the average person) would be
at its limit
of resolving detail of less than one minute of arc. Even
has more bandwidth, spectral energy, or detail, the images at
viewing angle would look similar.
typically can display about 72 dots per inch. A 21 inch
a .28 dot pitch could display up to about 1200 horizontal
is less than HDTV's 1920 pixels. Making the screen larger with
the same .28
dot pitch we reach a point where the tube would be too large
to get it through
the average doorway. Therefore it appears that the
screen for a CRT device would be about 34 inches and could
1920 horizontal pixels. The minimum viewing angle for this
would be 32
degrees and you would be 4 ft. from the display. Any closer and
you would exceed
the minimum viewing angle and your eye would start picking
in the image. Further away the viewing angle would be less
than the minimum
and the image would look fine except smaller.
If the viewer
was at a distance of 8.5 feet, then the NTSC image would NOT
look as sharp
as the DTV or HDTV image.
is that in the NTSC image we only have about 360 lines of
Now if you take that vertical resolution and bump it
Up to a 16x9
screen to get square pixels the horizontal pixels needed would
be 640 and now you could view the display
at the 12 degree viewing angle.
This DTV 16x9
wide screen image would look much sharper than a NTSC 4x3
image with its
fixed vertical resolution.
Now we get into
what HDTV is about. From a viewing distance of 13 ft., the
same as for
a 27 inch diagonal NTSC display, the screen size jumps up to a
and wider screen. A screen for this new 32 degree viewing angle
would be about
7.5 ft. x 4.2 ft. Perfect for the home where the ceiling to
is about 8 ft.
So what would
the viewer like in his home, a standard 27 inch TV as we know
it today or
HDTV-DTV with a BIG and WIDE screen?
some of the new displays cannot display all of HDTV's
1920x1080 pixels. A higher dot or pixel pitch will display a
Some viewers will opt for smaller screens. The plasma
flat panel display
comes to mind. It is in the wide screen 16x9 aspect
ratio but, because
of its lower resolution, the viewing angle will have to
It will not be able to display all of the spectral energy or
detail in the
I have said,
in a previous DTV Tech Notes, that camera personnel will have
to learn how
to frame for this big wide screen as there is not any
to compose for both 4x3 SDTV and 16x9 SDTV or HDTV on DTV.
Thorpe thinks that 16x9 SDTV will hold up quite well when
bumped up to
HDTV, especially if the images are shot with a narrow-taking
angle with lower
spectral energy (less bandwidth). A good reason to
consider a 16x9
wide screen camera.
A wide screen
27-inch diagonal DTV in 16x9 SDTV would definitely look
a 4x3 NTSC image at a viewing distance of 8.5 ft.. The NTSC
I hope this
helps shed some light on why HDTV is meant for the Home
why SDTV in wide screen would produce a better picture on a
of limited resolution. For Big Wide Screens, you cant beat
Summing it up,
the wider the viewing angle, the higher the bandwidth,
pixels, more detail, more bandwidth and more spectral
From: THE CGC COMMUNICATOR #209
Monday, December 8, 1997
BIDDING FOR COMMERCIAL AND ITFS LICENSES -
FULL NPRM TEXT
DETAILS OF THE
BROADCAST APPLICATIONS FREEZE
While the Commission
is formulating competitive bidding
rules (see above
story), it has imposed a freeze on some
broadcast applications. Paragraph 61
of the above linked
text reads as
...As an interim
measure, we shall, effective upon the
release of this
NPRM, impose a temporary freeze on the filing of
in all commercial broadcast and secondary
broadcast services, pursuant to our existing
we will continue to accept and process petitions for
requesting the allotment of new FM channels to the FM
Table of Allotments
at any time, and applicants will be able to apply
for any such
allotments during subsequently announced FM auction
filing windows. The freeze will apply
to applications for new
for major changes in existing facilities but not to
minor modification applications. It
will also not affect the filing
for new stations or for major changes in existing
the reserved portion of the FM broadcasting band
(Channels 200-220). Additionally, we
will exempt from the freeze
timely filed in response to an outstanding AM (or FM
cut-off list or to an open FM window, but we will not
issue any new
cut-off lists or open any new filing windows.
FCC SEEKS COMMENTS
ON FILING ADDRESSING DIGITAL TV ALLOTMENTS
20, 1997, the Association for Maximum Service
Inc. and other broadcasters (MSTV) submitted an
ex parte filing
that presents suggestions for addressing two
to the Table of Allotments for digital television
(DTV).... The first of these issues
concerns DTV-to-DTV adjacent
channel assignments. The second concerns
assignments in the most
of the country the Northeast, Great Lakes region,
Comments are due by December 17. It
is unlikely that this date
will be extended. To find out more,
(Ed Note: Thanks CGC Communicator)
Subj: A new book for your reference library
From: Larry Bloomfield
At the suggestion of Graham A. Jones, Engineering
Director of Harris' DTV Express, I picked up a copy of "Issues
in Advanced Television Technology," ($34.95 US - Soft Cover)
by S. Merrill Weiss. Although this book is a little pricey
for a soft cover, it is packed with a wealth of information.
It was not a book that I read comfortably, cover-to-cover, and enjoyed.
If approached on a subject-by-subject basis however, I found it
to be interesting and informative. Since I don't have a photographic
memory, Ill certainly keep it as a valuable part of my growing reference
library. From what I read, it was not hard to ascertain that
this work is an anthology of articles written by the author from
his Advanced Television column in "TV Technology" magazine
with one big exception: All the material has been updated,
is indexed and, most important, is current and timely.
Weiss covers the subjects of digital video
compression, transmission of digital signals, audio compression,
adaptive equalizers, packetization, transport and program streams,
multiplexing, MPEG-2, serial digital jitter, storage and servers,
data broadcasting, and the motivations of the players in the media
of the future. These are subjects that I hear executives at
the networks giving public talks about that would have been better
prepared had they read up on the subject matter in this book.
The author is obviously well informed and
the material is presented in a relaxed, conversational style and
his explanations are easily understood. The presentation
of material is aided by the use of nearly 60 figures and 35 tables
that help the reader understand even the more obtuse points.
The back cover implies that this is not a textbook, but I disagree.
Having taught Junior College for nearly ten years, I believe it
would make a good textbook on the subject matter. The publishers,
Focal Press, says that this is a book suited for and is of value
to business managers making strategic decision, technical managers
forming implementation choices, as well as system designers and
operators preparing for future work assignment. I agree with
them except for the business managers part. I have always
been of the opinion that when bean counters stick their noses into
things they don't know or understand, we end up with a camel instead
of a horse. It is an excellent book for technical types,
but I do not recommend it for anyone with out the background.
In closing, I d like to thank Graham for the
suggestion. You too will value having this book, "Issues
in Advanced Television Technology" as a part of your
(Ed Note: This is a web site worth looking
into. We've published their Dec. 3rd Headlines FYI.
Check them out.)
Subj: SCRI's Broadcast / Pro Video News Briefs
- December 3rd, 1997
From: SC Research International
Headlines Email Version. - news and
views on broadcast and video production sectors, worldwide -
The complete reports and articles listed in these News Briefs are
in the new SCRI Insider Report at http://www.scri.com
SGI Demos Integrated
HDTV / SDTV Post-Production Solution At SMPTE
Communications Tower in U.S. Obtains Final Approval
Halts German Digital TV Pact
Single-Chip MPEG-2 Encoder
Impact of DTV
on Translators and LPTV - A Larcan Presentation Report
Sony Delivers More Than 100 API's For
DVB Set-Top Box and DVD Applications
Commercial Introduction of Internet Access Via Open TV Web
Wave Phore to
Broadcast WSJ Interactive Over VBI of TV Broadcast Signal
Interactive TV Sets - NBC Announces First Wink Enhanced Broadcasts
New Telco Solution
To Provide Interactive Multimedia Services Using
Dishes Ruled Illegal In Canada
VDI Media Acquires
Fast-Forward Inc., SF's largest Video Duplication House
Software Inc. Announces National Television/Internet Joint Venture
In Crowded Japan Digital TV Market
tie up to develop chips for consumers
Pump Resources Into Digital Video Technology Initiatives
Discontinue Older Grass Valley Group Products
Gets a Buy Rating From BancAmerica
Arm Expected to Hit $10 Billion Revenue Mark
Corporation Revenues and Profits Up
Provides Entry into the Analog and Mixed Signal Technologies Markets
Betacam Used By Video Game Developer
New Tek Announces
Limited Time, Light Wave 3D 5.5/Film Grain Bundle
at Comdex to FOCUS Enhancements PC-to-TV Chip
New PC-TV Convergence
Solution at Comdex Goes Beyond The Little Black Box
LBT 4040 Prototype
Cable Modem Chip to Be Demonstrated at Cable Net 97
New WAN Access
Products and Higher-Density ATM Provide High Performance
and Video Service Integration
New Fiber Optic Broadband Platform Provides Cost
Increased Revenue Potential
PEOPLE IN THE
Chief Engineer and DTV Expert Available
Seen Unchanged as Exec Leaves
Citadel Entertainment and Retains David Ginsburg as Citadel CEO
the Web Increasing in Importance as a Source of Product Information
and Pro Video Users
Online at: http://www.scri.com/sc_subscribe.html
or via E-mail
_ 1997 SCRI,
Inc. 1317 Third Avenue, Suite 100, NYC, NY 10021
Tel: (212) 867-6060
| Fax: (212) 867-6579 | email:firstname.lastname@example.org | For access to Full
Text Articles & Reports, go to SCRI's website at: <<<
Subj: Hi Def hardware sample
FROM: Shelly Jacobs, Managing Director, MEDIA
Studios Hi Def Telecine page at:
Subj: Lest we forget.......
From: Larry Bloomfield
this is the holiday season, we thought we'd digress a little from
our more serious side and make a few observations. There are
terms we use every day in our business and never give them a second
thought. This newsletter is called DTV -- (digital television)
technical notes. Why ? And what is digital? Our
dictionary says: "Digital - adj. 1. Having digits.
2. Expressed in digits, especially for use by a computer."
A more correct term would be Binary. Just think
"BTV Tech Notes." Why? Using the same authority
as before, the dictionary: "Binary - adj. 1. Characterized
by or consisting of two parts or components; twofold. 2. Of or relating
to a system of numeration having 2 as its base."
So we say digital and really mean binary. Go figure!
For the sake of sanity and this article, we'll use the terms interchangeably.
definition of terms would not be complete if we didn't look at the
definition for the word television: "Television - n.
1. The transmission of visual images of moving and stationary objects,
generally with accompanying sound. 2. The industry of
producing and broadcasting television programs." We could
fill a book on definitions alone. We'll not do that;
let's just continue.
the book that was reviewed in our last issue, one would think that
digital television was something relatively new. We don't
think so! We've been using both visual and non-visual
digital or binary techniques in communications for centuries.
We're talking a long time and then some. Your knee-jerk reaction
is to say that the author has lost it. Not so. Using
the definitions above, aren't "smoke signals" visual images
of moving, binary or digital information. What about
the flashing lights the Romans used thousands of years ago?
If you'll permit us to remove the visual part of our definition,
we can include the beating of drums. To be more picturesque,
you can call them jungle drums. But isn't that still digital
and still communicating?
purists would say that the communications we are speaking of has
to be electronic. OK then, several years before the famous
message , (What hath God wrought?) was sent between Baltimore and
Washington, DC, the principals of telegraphic communications
had been demonstrated. This truly is binary or digital communications.
what about compression. Compression is the principal or concept
of packing more information into a given time and space. If
that's true, the early telegraphers used automatic keyers and in
the early demonstrations of telegraphy, the message was actually
recorded on paper by an inking device for decoding (now there's
a familiar term) at a later time. As the telegraph gave way
to the Teletype, they even employed compression then too when
they used electromechanical keyers and the streams of punched paper
tape. Are we reinventing the wheel? Is what we are doing
really all that new? Well I'm sure many of you can come up
with more examples. I had fun writing this and thinking of
the ancient possibilities. The idea of all this was to have
fun and just get you thinking Well that's our excursion into
De Ja Vue. Thanks for putting up with our conjectures.
Hope you had as much fun reading this as I did writing it.
Subj: Some things to consider.....
and not just for the newcomers.
From: Larry Bloomfield
this is the time of the year that most everyone reflects, we'll
leave you with these few thoughts: When all those around us
say that something can't be done, why does it usually take someone
who doesn't know that he or she can't do it, to succeed and make
it happen? It could be that they never let what they can't
do interfere with what they can do. If you think you can,
you can. And if you think you can't, you're right. I
guess, as Thomas Edison said: "If we did all the things
we are capable of doing, we would literally astound ourselves."
me to share with you some thoughts which I made into notes a long
time ago. These thoughts have been developed over the years.
Some are original. Some are not. It's been so long since I
began these notes and they have been refined time and time again,
I truly can't remember the source of most of them. I do share
these thoughts with every student of mine, be it in the classroom
or on-the-job. Feel free to use them as you see fit
and if you have anything to add, please send them to me. Here
understand thoroughly the basics. They are of the up most
importance. The basics are the building blocks of the remainder
of your carrier. Don't take lightly the history of our industry.
Have a good knowledge of how things began. They say that those
who don't know history are condemned to relive it. In your
work habits, if you know how, you'll always have a job. If
you know why, you'll be the boss. Commit yourself to quality
from day one. Just remember that your chances of being run
over are doubled if you stay in the middle of the road. On
the other hand, if things aren't moving fast enough, consider the
turtle_ It can't move at all if it doesn't stick its neck
out. Don't try to do something cheaply that shouldn't
be done at all. It's better to do nothing at all than to do
it badly. The bitterness of poor quality remains long after
the sweetness of meeting the schedule has been forgotten.
The fastest runner does not always win the race. Sometimes
those who just keep running, win it. If, however, in that
race you come to a turn in the road, (and you will), it's not the
end of the road unless you fail to make the turn. Avoid short
cuts. They always take too much time in the long run.
If you wish to finish sooner, take your time. People, however
who wait for all conditions to be perfect before acting, never act.
will not always agree with your fellow engineers, but worrying about
what's right is always more important than worrying about who's
right. People take different roads to achieve success.
Just because they're not on your road doesn't mean they've gotten
lost. If you must go into battle, be thoroughly prepared.
It's better to win the first time. It's not weather you get
knocked down. It's weather you get up again. The guy
who makes no mistakes usually doesn't make anything. Learn
from the mistakes of others. You won't live long enough to
make them all yourself. Never be afraid to say, "I don't
know" -- The important people will respect you much more and
will always place more weight on what you do say.. because they
know you're right. Beware, because people who will lie for
you, will lie to you.
don't think you are making enough money, just remember that wealth
comes to those who make things happen and not to those who let things
happen. Stay on the cutting edge. Keeping up is always
easier than catching up. If you think education is expensive,
wait till you see what ignorance costs you. If you keep doing
what you're doing, you'll keep getting what you're getting.
Never underestimate the importance of money. Right or wrong,
it's how business people keep score! On the other hand, never
overestimate the value of money either. Cash is important,
but sometimes not as important as respect, thanks, integrity, or
the thrill of a job well done. Try to convince your employer
to spend the extra dollars to maintain the equipment properly.
It's like brushing your teeth -- you only brush the ones you want
to keep. If you are a competent engineer and your employer
doesn't listen to your suggestions, get a second opinions.
If this situation continues, get a second employer. Document
all that you do. Not many of us have photographic memories.
information and education are priceless. Get them at any cost.
You can not afford not to.
Those are my standards, what's yours?
event we do not put out another issue of this newsletter before
the holidays, Happy and Merry Everything.
A fairly knowledgeable (HDTV - DTV) engineer
is looking for an employer. If you are interested, please
advise and we will pass it on to him. Thanks.
Last minute item: From:
Just heard that
the Super Bowl Kick Off will be shot in HDTV. That will
in January of 1998.
More later. ---- Jim
The DTV Tech Notes are published for broadcast
professionals who are interested in DTV, HDTV etc. by Larry Bloomfield
and Jim Mendrala. We can be reached by either e-mail or land lines
(541) 385-9115, (805) 294-1049 or fax at (805) 294-0705. News
items, comments, opinions etc. are always welcome from our readers;
letters may be edited for brevity.
--------- J_Mendrala@compuserve.com <<<<<
DTV Tech Note
articles may be reproduced in any form provided they are unaltered
and credit is given to the DTV Tech Notes and the originating authors,