North West Tech Notes
Published by: Larry Bloomfield & Jim Mendrala
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We have copied the original Tech-Notes below as it was sent out.
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% Larry Bloomfield & Jim Mendrala
521 Forest Grove Dr.
Bend, Oregon 97702
Email = firstname.lastname@example.org J_Mendrala@compuserve.com
July 21, 1997
NWTN - 006
This effort will be successful
ONLY with the assistance of those who help by contributing information
to us and have the professional desire to keep us all on the cutting edge
of this technology. We need you to share your experiences, knowledge
or anything else relating to DTV, HDTV etc. We will share what we
get from you. This is a work of love. We see a need and we're doing
this solely with the idea of keeping ourselves and our associates informed.
We ask no compensation for our efforts, just the latest information you
may have on what's going on. We will not pass on anything that cannot
be verified or the source cannot be identified. If we inadvertently pass
on erroneous information, we will make every effort to get it corrected
as soon as possible. The above disclaimer is for obvious reasons.
Who will we send these
issues to? We will make every effort to share this effort with
our fellow broadcasters: Anyone interested!. Just e-mail us your
request to be added to the mailing list and it's done! Feel free
to forward this on to your associates, but let them know that you've done
so and it's not directly from us. If we've sent this to you and you're
not interested, just let us know and we will take you off the mailing list.
(Bob Gonsett) ----- and the THE CGC COMMUNICATOR (Electronic Edition)
#170 - Wednesday, July 16, 1997
DTV TRANSMISSION STANDARD
VOTE SET FOR NEXT WEDNESDAY
John Henderson, who chairs
the ATSC committee responsible for "Compliance," indicates that the Digital
Television Transmission Measurement and Compliance standard will be voted
on this coming Wednesday, July 23. We plan to publish the URL where
the document can be viewed assuming the vote is favorable.
This document will not
answer all questions. Work remains to be done on channel and digital
"sub channel" identification, on interoperability, on data broadcasting,
on layered video and the like. However, publication of the Measurement
and Compliance standard will move the RF folks a giant step forward.
Several years ago Dynair had an interesting thing they called "The Order
of The Iron Test Pattern." I know several other engineers who happily
displayed the membership certificate etc. I always thought it was
kind of a fun thing. Bob Venderland, through Bob Gonsett, has written
us here at NWTN with the following. He is trying to revive "The Order
of The Iron Test Pattern." In addition to what is below, you might
contact him or visit their web site to see what it is all about.
From: Robert Vendeland
The Order of The Iron
Test Pattern is starting a speaker's bureau which may be of interest to
some of the recipients of your digital television news letter. In many
cases a television engineer would welcome the opportunity to talk before
a local service club in his or her community on technical subjectssuch
as the impact of digital television on the consumer. However, most
engineers we know hesitate to push themselves forward as volunteers.
It is for this reason
that the Order plans to introduce, on our elegant letterhead, interested
engineers to the program chairmen of Kiwanis, Rotary, Chambers of Commerce,
etc. in their communities. Our letter will say that (the engineer,
resume and photo will be enclosed) is in our speaker's bureau and is prepared
to talk to their group on the (subjects selected by the speaker).
We will send a brief description of the Order, and the fact that we survive
because we have a sense of humor and can explain complicated concepts to
management in words they understand.
To make this happen, we
request that the volunteers send a very brief bio-sketch to us along with
a photo that we can scan and laser print for attachment to the letter of
introduction. Our letter will contain all information necessary for
the program person to contact the engineer directly to make whatever arrangements
are acceptable to the engineer.
Except for the introduction,
we are not in the loop. We'll send up to three letters per volunteer
and are confident that this service will be of great public relations value
to the engineer and the engineer's employer. Most important, it has the
potential for bringing more fact than fiction to the public ---- especially
in the area of digital television.
Our address is:
Order of The Iron Test
5751 #D Palmer Way
Carlsbad, CA 92008
E-Mail is: email@example.com
Web Site is: logoinc.com/irontest
Robert N. Vendeland
(Ed note: Eric
Dausman is the Director of Engineering at KGW in Portland, OR. Eric
was a significant contributor to the SBE luncheon recently in Portland
on the subjects we speak about here in our newsletter.)
EricD@kgw.com (Dausman, Eric)
Here are some comments
I passed on to the AH Belo organization.
Subject: DTV Discussion
I'm a little confused.
Why are we debating the politics of the DTV mandate that has been essentially
cast in stone? DTV is our future, especially if we go do it, and
do it smartly. Consumers have been asking for better television for
years. They just didn't know what to ask for. The major complaint
has nothing to do with scanning lines, and resolution. The big issues
for most consumers are ghosts and snow.
I spend a lot of time
on the phone with viewers talking about TV reception.
We are giving away a lot
of our NBC viewers to satellite every month for one reason only.
They get a much better picture off the DSS dish! We can not compete
with a crisp clean picture void of any ghosts or noise in the rural areas
of our market, and even in some of the urban and sub-urban areas.
Viewers are getting smarter
and smarter. They are demanding better video. If we do not
provide it, someone else will. I believe that our analog days are
numbered simply by the fact the electronics industry is going to push digital
video "stuff" such as TV's, VCR's, even games, because it is good for their
business. In the end, most consumers will not buy a new TV on the
specs for lines of resolution, but for how many inputs does it have to
take advantage of digital technology. Remember how fast they changed
the record industry. Everyone complained at first about the high
cost of machines. Within two years of the introduction, there were
$199 CD players. No one ever spent $199 on a turntable for their
stereo. Consumers were willing to spend the additional money
because they saw the add value of the CD!
Everyone seems to agree
on one point. There will be very few true HD
displays available to
the public simply because of the cost. In my opinion, true HDTV is
at the bottom of the consumers list of features they want.
First, they want good
looking images, void of ghosts and noise. Second, they want larger
screens, wide would be nice. Third, they want decent audio.
Decent audio does not need to be surround sound. It just needs to
be good and clean, and the commercials better not be louder than the program
It goes without saying
that consumers expect that the new TV set will be compatible with existing
NTSC, DTV signals, cable digital signals, DSS signals and the like.
There will be some sort of consumer video jack standardize for home use,
and it may be as simple as analog component signals or maybe eventually
truly digital. This way they can plug all the components the electronics
industry is going to sell them together.
Nowhere on this list is
more TV channels or "laboratory grade" HDTV! It will simply be to
expensive a "feature" to be purchased by most.
Enter DGTV resolution--
Now, how do we get the
consumer what they want? We all know that we could deliver better
pictures from our studios than we can deliver to the home. Some of
us already do this. (KGW is not one of them. I still air news
on 3/4 inch, remember!) This is simply because our origination and production
equipment can now be much better than our transmission system will allow.
We should equip ourselves
to do the best job possible for the foreseeable future--that "infinite
5 years". The only way we can do this at a reasonable cost and in
the allotted 18 to 30 month time frame is with good quality stuff we can
buy now. This means that we should be looking at a widescreen 525
line rate component serial digital plant with the added bits for widescreen.
Lets call this Widescreen 525 CSD or W525CSD for short. I think
SMPTE has another name for this by now. I call meeting the consumers
need for lack of noise, lack of ghosts, wider screen, and better audio,
DGTV, which is short for Damn Good TV!
We could buy some true
HD routers, switchers, and even DVE's now, but you will not be able
to deliver the production value to your programs that your viewers are
accustom to. Besides, they are way to expensive.
If your network really
provides you with a HDTV signal, then you will need a bypass path around
your production systems, and a down-converter to bring the signal into
your W525CSD. This will allow you to integrate commercials, ad supers,
dissolves, and all those things the promotion department wants. At
the output of our "master control" we will need to be able to up convert
to DTV, and encode to NTSC. The best part of all of this--our NTSC
is going to look better than ever!
As a group, we need to
consolidate our thinking into one voice. Don't get me wrong, I am
not against buying true HDTV equipment, I just feel that the viewer may
never see it until the second "infinite 5 years". Until then, DGTV
will suffice, because this is what the consumer wants, and this is what
will be available.
I plan to comment about
many of the other issues, but I have other stuff to do like change a light
bulb above an anchors desk. Yes, I have to do that kind of stuff,
Subj: Digital Encoding
In my last few e-mails,
I have stated that MRC will use 34 Mbps QPSK to encode DTV/HDTV signals
onto a microwave radio.
As I said, we are all
learning. 34 Mbps is the European standard. MRC will be using
(Randall Paris Dark)
You said in your last
issue: "If you will recall, we touched on the lack of programming
in our last issue. Well it stirred up some feedback It seems
that there is a company in Texas which has been producing "Digital High
Definition" television for the past eleven years, or so they said.
We were informed that they have done this in about every format requested."
I may have not been clear.
I have been producing High Definition for about eleven years but only the
past 4 years have I been doing it in Digital HD. The different formats
are based on the clients budgets. Some clients can afford the HDD-1000
VTR's, some clients can only afford THE Uni-hi format. However, all
of the clients use the production standard of 1125/60 Interlace.
(Ed Note: NWTN was
sent a copy of this e-mail correspondence for publication as it may be
of interest in the new HDTV world. Additionally we asked a local
dealer to get us a DXC-9000 for purposes of evaluation. We will advise
our readers as to our findings.)
Subject: alternate summed
You commented, "Sony has
a mini color CCD camera that progressively scans the image captured in
-1/60 of a second or less, and outputs an interlaced NTSC video signal."
FYI - I understand Sony's
HDC-500 (HD CCD camera) captures this way too, as indeed many CCD cameras
do. On the CCD (integral with the chip), 1/60/sec sampled Frame is
actually output (off the chip) as alternate summed pair lines, so presented
as interlaced fields. (I.e., field 1 = Frame1 lines 1&2, 3&4,
5&6..., field 2 = Frame2 lines 2&3, 4&5, 6&7...)
BTW: Advantage is effective halving of CCD noise.
Sony will not acknowledge
this is what they do... IAC, output as 1/60 Frames is only on-board the
CCD itself, and not available as an external signal.
- - - - - - - -
You are correct about
a conventional CCD image sensor, the vertical resolution is only about
350TV lines because of field integration techniques to match NTSC broadcasting
specifications. This was the result of the NTSC standard, which uses
two fields, each 262.5 scanning lines, interlaced at 2:1 to create a single
frame. since emphasis was placed on making the motion of a subject appear
smooth rather than providing a high vertical resolution, the conventional
CCD (IS-4T) mixed signal charges from two adjacent pixels vertically, outputting
262.5 line signals per field (i.e. per single exposure). The vertical resolution
is still insufficient compared to horizontal resolution. To resolve
this problem, Sony developed a progressive Scan CCD image sensor, which
does not mix signals in the vertical CCD.
The new DXC-9000 camera
provides three types of output signals, a 2:1 interlace scanning system
that can run in the "Normal Mode" (NTSC standard), outputting RGB,
Y/C and VBS, a "Frame Shutter Mode" (NTSC standard), outputting RGB, Y/C
and VBS and a VGA mode with a 640 x 480 RGB output.
In the "Normal Mode" the
odd field is provided from one image in 1/60 second and the even field
is provided from the next image 1/60 second later. The odd and even
field are output one after another, then interlaced together to form one
In the "Shutter Mode"
both the odd and even field are taken from the same image in 1/60 second.
The even field is put in memory and output after the odd field, then interlaced
together, in accordance with the 2/1 interlace scanning system. When
a high-speed moving object is shot, each frame image is clear, because
both the odd field and the following even field are from the same image.
In the "VGA Mode" the
camera produces an RGB VGA format with 640x480 signal. This works
with non-interlaced computer monitors. This is possible by increasing the
horizontal scan rate.
The Progressive Scan method
can read out information for each pixel individually in a single field
(1/60s), providing both high vertical resolution and high dynamic resolution.
The field and frame output
signals allow the camera to maintain complete system compatibility with
existing video equipment. The camera is also available as a progressive
In the film world, an
image is photographed (captured) in 1/50 second at a frame rate of 24 per
second. When these frames are scanned on a telecine scanner each
image is stored in a frame store and output as a standard NTSC signal which
is equivalent to the "Frame Shutter Mode" of the DXC-9000.
FYI: Price of the DXC-9000
starts at $6,500 w/o lens or optional accessories. The camera is
designed to accept 1/2-inch, 38mm bayonet-mount lenses. The lens
mount has a dual hot-shoe connection to eliminate the need for a lens-to-camera
interconnecting cable. This provides easy remote control of zoom, focus
and iris functions. 2/3-inch mount lenses can also be used with an
optional Lens Mount Adapter.
by Larry Bloomfield
I want to thank all those
who have shown such a positive interest in our NWTN publication and
a special thanks to those who have contributed their thoughts to these
pages. This past week was really great for me. I had the chance
to travel over the Cascades into Portland. A normal three hour trip
that the road maintenance folks added an unsuspected half hour or more
to. It was worth all the trouble. The occasion was the monthly
It is the grass roots
engineers who have always come up the solutions to the most complex of
issues in our industry. It was a pleasure to meet and speak with
those in attendance and a special thanks to the Portland SBE for permitting
me to share some of my views about DTV, HDTV etc. with them.
I feel we had a good meeting. I very much enjoyed the various views
and opinions that were expressed. If you don't go to SBE meetings,
you really should. Bring up some of the issues we address here in
NWTN and you'd be surprised at what others think and believe.
Sorry to the radio guys
who were there, but yes, we TV types do talk about the picture part of
our business and, in many respects, tend to forget about. The sound
systems on TV receivers has certainly improved over the old 3 inch speaker
stuck in the side of the plastic cabinet.
Having come from radio
originally, as I'm sure many of you have, we TV types can surely make good
use of the experiences the radio guys get in their areas as they see the
development and improvements in audio technology. The expertise
these gentlemen, who deal with audio on a more intimate day-to-day bases,
tend to develop a knowledge which should be shared with all of us.
There are also some interesting development in the area of digital radio.
Perhaps some of the techniques that are being used in this area of broadcasting
might have an application in television.
In any event, I have always
said, in jest, that you haven't lived the life of a true broadcast engineer
until you have had to build a multi-tower AM station from the ground up.
(Only someone who has done so can appreciate what I am alluding to here.)
Ah the tramping through neighbors yards with your Potomac on your shoulder.
Enough of that.
One of the things mentioned
was that we need to look at the changes in our industry in two lights.
One: generation and Two: distribution. It would appear that
we've almost succeeded in getting the cart before the horse. That
is to say that we have the RF part of the transition to DTV fairly under
control, but as was mentioned in our Portland SBE meeting, what the RF
carries is still up in the air. Until we know what the set manufacturers
are going to do, we won't know what to generate in our plants. To
be safe, as has been said in these pages before, buy what ever will capture
the highest pixel rate (information). This can then be stored in
a multiplicity of formats for recalled and translation to what ever format
may be required. The reason for mentioning this is that many station
are looking at new gear in the not too distant future. It does not
look good for an engineer to recommend something that will be obsolete
or unusable soon after it is purchased. Your comments are most welcome.
In our next issue I hoping
to have some information from Tektronix about Digital TV Measurements.
If you know of other manufacturers who are making test equipment in this
area of our business (DTV etc), please advise. Let them know about
NWTN or let us know so we can let them know. Also if there are any
consultant engineers reading these pages who deal with RF and are involved
with what we cover here in NWTN, please let us know what you are doing
and if there are any instances worth sharing with your fellow engineers.
Everyone with something meaningful will get space in these pages.
The NWTN is published
for broadcast professionals who are interested in DTV, HDTV etc. by Larry
Bloomfield, Chief Engineer, KTVZ, Bend, Oregon and Jim Mendrala, Consulting
Engineer, Val Verde, California. We can be reached by either e-mail
or land line (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.
firstname.lastname@example.org --------- J_Mendrala@compuserve.com
NWTN articles may be reproduced
in any form provided they are unaltered and credit is given to the North
West Technical Notes and the originating authors, when named.