Sign in with
Sign up | Sign in
Your question

VSB confusion New to HDTV and a few questions

Last response: in Home Theatre
Share
Anonymous
April 10, 2004 6:57:33 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

Hi,

I have my pcHDTV card up and running in linux. (www.pchdtv.com). I can get
all the usual channels in my area im pretty happy. I was having some weird
issues but changing the coax I used cleared it allll up.

But..

VSB... 8VSB, 16 VSB, QAM, COFDM (what ever it is) im reading some posts in
this newsgroup about them all.. soemone is bad mouthing 8VSB someone is
saying COFDM is better... what does it all mean?!

I thought the standard in the US for OTA was 8VSB. (the pchdtv card is
16vsb capable) but what is VSB MEAN!?

Is OTA HDTV doomed?
Ive read ALOT of posts about this... some people say OTA HDTV is doomed
because of 8 VSB and that no one is watching it this and that...

Did i buy a OTA hdtv card for my computer and make a mistake?
Will OTA HDTV live on?

I'm new to the whole HDTV thing.. so please excuse any ignorance above..
im learning and researching day and night!

Thank you
Nick D
Anonymous
April 10, 2004 10:29:41 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

On Sat, 10 Apr 2004, Nick D wrote:
> Is OTA HDTV doomed?
> Ive read ALOT of posts about this... some people say OTA HDTV is doomed
> because of 8 VSB and that no one is watching it this and that...

OTA HDTV is not doomed. What you are reading is a small, disgruntled
minority of individuals.

Here's what I've been able to put together:

The supposed superiority of COFDM only exists in relatively small and
quite densely-populated areas. COFDM deployment is much like cell phone
deployment: lots of small transmitters to cover a service area. This is,
not coincidentally, how TV has traditionally worked in Europe and Japan.

Note that suburbs (as we understand them in North America) are very
definitely a North American phenomenum. Elsewhere in the world, you can
literally cross a street from city to rural.

In North America, TV traditionally serves a large geographic market area
from a single transmitter per broadcaster. 8VSB works better than COFDM
in these circumstances.

The #1 disgruntled individual is located in Manhattan, and like most New
Yawkers thinks that civilization ends outside the boundaries of NYC.
COFDM may well do better than 8VSB for OTA reception in Manhattan. This
individual has a web page for his company; it just consists of an SWF
animation and a mailto link to him. This gives you an idea of how real he
is.

Lately, he's been sprouting forth conspiracy theories -- the earmark of a
kook. In fact, it was when he started with the conspiracy theories that I
realized that there was no issue in favor of COFDM. Instead, it's just
like those crackpots in the 1980s that were saying we should abandon NTSC
for PAL.

So, if you think that only places like NYC count, and people who live in
suburbs and rural areas should put up with the same level of reliability
you get with cell phones, then you will love COFDM.

If, on the other hand, you think that TV towers are not going to appear
all over the landscape, you don't want to wait until a tower is built in
your neighborhood before you get TV, and you want HDTV (most COFDM is not
HDTV capable) you would prefer 8VSB.

-- Mark --

http://staff.washington.edu/mrc
Science does not emerge from voting, party politics, or public debate.
Si vis pacem, para bellum.
Anonymous
April 11, 2004 3:07:08 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

Wow...

I learned more in these last two posts then ever.

Thank you VERY much for the information!

Tonight.. i enjoyed "The whole nine yards" in HD and "The District" in HD.
Boy am I glad I got an HDTV card :-D

Nick D
Related resources
Anonymous
April 11, 2004 6:45:17 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

Nick D wrote:

>Hi,
>
>I have my pcHDTV card up and running in linux. (www.pchdtv.com). I can get
>all the usual channels in my area im pretty happy. I was having some weird
>issues but changing the coax I used cleared it allll up.
>
>But..
>
>VSB... 8VSB, 16 VSB, QAM, COFDM (what ever it is) im reading some posts in
>this newsgroup about them all.. soemone is bad mouthing 8VSB someone is
>saying COFDM is better... what does it all mean?!
>
>I thought the standard in the US for OTA was 8VSB. (the pchdtv card is
>16vsb capable) but what is VSB MEAN!?
>
>
8VSB - VSB=Vestigal Side Band - a way of encoding a bit stream on a
network. This is the current standard for US (ATSC) and some other
countries. Unfortunately, there are competing standards and factions -
think VHS vs. BETA but many more competing groups.

>Is OTA HDTV doomed?
>
>
It might change someday. Your current standard is relatively safe as
conversions from the original source to your "outlet" can happen. The
Broadcasters have one position, the Cable providers another, other
countries a third, etc. Most, if not all, can be converted, and if you
are getting your signal from a cable, it won't matter.

>Ive read ALOT of posts about this... some people say OTA HDTV is doomed
>because of 8 VSB and that no one is watching it this and that...
>
>
It may not have been the best choice, but it was chosen. Is 120V 60Hz
the best electricity? Which to choose: DVB-S, DVB-C, DVB-MC, DVB-T, and
is the Reed-Solomon Encoder the best choice? I say, good enough is Good
Enough. I really thought some QAM version was going to win, but it
didn't, and I'm not shedding a tear.

>Did i buy a OTA hdtv card for my computer and make a mistake?
>Will OTA HDTV live on?
>
>
>
Relax. Enjoy a better picture than you had previously - it will be some
(significant) time before the choices made will change again. Your
computer will be an antique before you have to worry about this issue.

>I'm new to the whole HDTV thing.. so please excuse any ignorance above..
>im learning and researching day and night!
>
>Thank you
>Nick D
>
>
Anonymous
April 11, 2004 6:45:18 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

In article <1j2ec.5024$Fo4.58286@typhoon.sonic.net>,
cmilono@cmilono.com says...
> 8VSB - VSB=Vestigal Side Band - a way of encoding a bit stream on a
> network. This is the current standard for US (ATSC) and some other
> countries.

Vestigal (from vestige, in the sense of part of) side band has
nothing particular to do with networks. When one amplitude modulates
a transmitter, two identical sidebands are created, one below the
carrier frequency, and the other, a mirror image, above the carrier.
In basic AM, 50% of the power is contained in the carrier, and 25% in
each side band. Thus only 25% of the signal is transmitting unique
information.

In analog TV transmission, VSB is used to eliminate most of one
sideband (hence vestigal) before amplification and transmission.
This reduces the needed transmission bandwidth in half (almost), and
allows a larger percentage of the power to go toward carrying the
signal content. VSB has been used for analog TV for fifty years in
the US and most other countries.

In the VSB transmission standard adopted for digital TV, one of the
sidebands and most of the carrier are suppressed, and all the power
is used for the remaining sideband, greatly increasing the coverage
for a given transmitter power. The mostly-suppressed carrier is not
completely removed to make locking onto the signal by the receiver
easier. If you think of plugging a common computer modem into the mic
input of an SSB (single sideband) transmitter, you have a first-order
approximation of how digital TV is transmitted.

/Chris, AA6SQ
Anonymous
April 11, 2004 6:45:19 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

That was impressive.

Thanks Chris. Do you have a visual representation of what you just
explained? Is there a website where I can go to see this stuff? I'm a visual
learner.

Doug


"Chris Thomas" <cthomas@mminternet.com> wrote in message
news:MPG.1ae25f6dc1d2b242989818@news.mminternet.com...
> In article <1j2ec.5024$Fo4.58286@typhoon.sonic.net>,
> cmilono@cmilono.com says...
> > 8VSB - VSB=Vestigal Side Band - a way of encoding a bit stream on a
> > network. This is the current standard for US (ATSC) and some other
> > countries.
>
> Vestigal (from vestige, in the sense of part of) side band has
> nothing particular to do with networks. When one amplitude modulates
> a transmitter, two identical sidebands are created, one below the
> carrier frequency, and the other, a mirror image, above the carrier.
> In basic AM, 50% of the power is contained in the carrier, and 25% in
> each side band. Thus only 25% of the signal is transmitting unique
> information.
>
> In analog TV transmission, VSB is used to eliminate most of one
> sideband (hence vestigal) before amplification and transmission.
> This reduces the needed transmission bandwidth in half (almost), and
> allows a larger percentage of the power to go toward carrying the
> signal content. VSB has been used for analog TV for fifty years in
> the US and most other countries.
>
> In the VSB transmission standard adopted for digital TV, one of the
> sidebands and most of the carrier are suppressed, and all the power
> is used for the remaining sideband, greatly increasing the coverage
> for a given transmitter power. The mostly-suppressed carrier is not
> completely removed to make locking onto the signal by the receiver
> easier. If you think of plugging a common computer modem into the mic
> input of an SSB (single sideband) transmitter, you have a first-order
> approximation of how digital TV is transmitted.
>
> /Chris, AA6SQ
Anonymous
April 11, 2004 8:52:01 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

Carlo Milono wrote:
> Nick D wrote:
>
>> Hi,
>>
>> I have my pcHDTV card up and running in linux. (www.pchdtv.com). I can
>> get
>> all the usual channels in my area im pretty happy. I was having some
>> weird
>> issues but changing the coax I used cleared it allll up.
>>
>> But..
>>
>> VSB... 8VSB, 16 VSB, QAM, COFDM (what ever it is) im reading some
>> posts in
>> this newsgroup about them all.. soemone is bad mouthing 8VSB someone is
>> saying COFDM is better... what does it all mean?!
>>
>> I thought the standard in the US for OTA was 8VSB. (the pchdtv card is
>> 16vsb capable) but what is VSB MEAN!?
>>
>>
> 8VSB - VSB=Vestigal Side Band - a way of encoding a bit stream on a
> network. This is the current standard for US (ATSC) and some other
> countries. Unfortunately, there are competing standards and factions -
> think VHS vs. BETA but many more competing groups.

The competition is pretty much over. COFDM or a version of COFDM has won
in most countries. The ones that are left are mostly expected to also
chose COFDM. All countries that tested the two and made a choice based
on science chose COFDM. S. Korea made a choice for 8-VSB based on the
fact that one of its major industrial corporations, LG Industries and
parent of Zenith, owns most of the IP (royalty rights) to 8-VSB. The
only other country that has chosen 8-VSB is Canada and they did so
because most of their population lives within a hundred miles of the US
border and they feel they have to follow be compatible. Mexico MAY (has
not yet) also make a decision for 8-VSB for the same border issue.
>
>> Is OTA HDTV doomed?
>>
>>
> It might change someday. Your current standard is relatively safe as
> conversions from the original source to your "outlet" can happen. The
> Broadcasters have one position, the Cable providers another, other
> countries a third, etc. Most, if not all, can be converted, and if you
> are getting your signal from a cable, it won't matter.

It is nice to know that if you get your signal from cable it doesn't
matter if OTA HDTV is doomed. The fact is that few people are buying OTA
HDTV receivers and for good reason. Most people either are to young to
remember needing a rooftop antenna or are old enough to remember making
the decision that they didn't want to depend on a rooftop antenna and
chose to go with cable or satellite.

OTA broadcasting is doomed if as is happening now no one buys it. Even
with the mandate I expect most people to ignore the OTA receiver and
hook up to cable or satellite. As time goes on Congress and the FCC will
notice (AS THEY ARE BEGINNING TO NOW) that few and fewer every day
depend on OTA TV. One day it will be politically survivable to suggest
that we the owners of this spectrum take it back from the broadcasters
and use it for something else. That is why you see the trial balloons
form the Chairman of the FCC the last few weeks and the REQUEST of
Chairman of the Commerce Committee, Billy Tauzin, for the General
Accounting Office to look into the success in Berlin where they had a
NINE month DTV transition. From the beginning to the turn off of all
analog broadcasting only took NINE MONTHS!!! And they already had 12%
penetration. Compare that to our less than ONE % after 7 years.

The difference, they have COFDM we have 8-VSB.
>
>> Ive read ALOT of posts about this... some people say OTA HDTV is doomed
>> because of 8 VSB and that no one is watching it this and that...
>>
>>
> It may not have been the best choice, but it was chosen. Is 120V 60Hz
> the best electricity? Which to choose: DVB-S, DVB-C, DVB-MC, DVB-T, and
> is the Reed-Solomon Encoder the best choice? I say, good enough is Good
> Enough. I really thought some QAM version was going to win, but it
> didn't, and I'm not shedding a tear.

The only one that you list that could be chosen for terrestrial OTA is
DVB-T. DVB-S = satellite, DVB-C = cable, DVB-MC is for microwave cell.
COFDM is QAM or QPSK but most implementations uses QAM.
>
>> Did i buy a OTA hdtv card for my computer and make a mistake?
>> Will OTA HDTV live on?
>>
>>
>>
> Relax. Enjoy a better picture than you had previously - it will be some
> (significant) time before the choices made will change again. Your
> computer will be an antique before you have to worry about this issue.
>
>> I'm new to the whole HDTV thing.. so please excuse any ignorance above..
>> im learning and researching day and night!
>>
>> Thank you Nick D
>>
>>
>
Anonymous
April 11, 2004 9:44:13 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

Mark Crispin wrote:

> On Sat, 10 Apr 2004, Nick D wrote:
>
>> Is OTA HDTV doomed?
>> Ive read ALOT of posts about this... some people say OTA HDTV is doomed
>> because of 8 VSB and that no one is watching it this and that...
>
>
> OTA HDTV is not doomed. What you are reading is a small, disgruntled
> minority of individuals.
>
> Here's what I've been able to put together:
>
> The supposed superiority of COFDM only exists in relatively small and
> quite densely-populated areas. COFDM deployment is much like cell phone
> deployment: lots of small transmitters to cover a service area. This
> is, not coincidentally, how TV has traditionally worked in Europe and
> Japan.

All areas of the world have picked DVB-T COFDM or another version of
COFDM. COFDM allows for the use of SFN's and on channel repeaters. This
advantage is one that is being investigated by 8-VSB types. This
advantage does not limit COFDM's ability to broadcast off one big tower
at high power, it just make that way of broadcasting obsolete.

In lab test COFDM was found to have a small power disadvantage. In the
REAL world this disadvantage was investigated by every country that
tested the two. ALL found that it was insignificant including places
like Australia and Russia with big open spaces. Last I heard Australia
has suburbs. What is remarkable about Australia is that they originally
were going for 8-VSB and reversed their decision even under major
pressure from the US after testing COFDM and 8-VSB. THE MAIN point that
the ATSC of the US kept harping on was the power differential. Australia
dismissed it as INSIGNIFICANT!!!

And I stand on my challenge to all to test COFDM and 8-VSB. Pick a spot,
any spot in any coverage area where you can receive 8-VSB and under the
same power level We will drive around your 8-VSB antenna receiving COFDM
mobile.
>
> Note that suburbs (as we understand them in North America) are very
> definitely a North American phenomenum. Elsewhere in the world, you can
> literally cross a street from city to rural.

Not Australia.
>
> In North America, TV traditionally serves a large geographic market area
> from a single transmitter per broadcaster. 8VSB works better than COFDM
> in these circumstances.

Simply not true. In any given coverage area COFDM will be easily
received by at least 40% more people with simple antennas than 8-VSB at
the same power level.
>
> The #1 disgruntled individual is located in Manhattan, and like most New
> Yawkers thinks that civilization ends outside the boundaries of NYC.
> COFDM may well do better than 8VSB for OTA reception in Manhattan. This
> individual has a web page for his company; it just consists of an SWF
> animation and a mailto link to him. This gives you an idea of how real
> he is.

Well I am originally from Michigan and we will be setting up COFDM there
soon so we will see. New York is the most RF challenged environment for
any type of broadcast system. Good place to test. COFDM will work better
in Montana that 8-VSB also.
>
> Lately, he's been sprouting forth conspiracy theories -- the earmark of
> a kook. In fact, it was when he started with the conspiracy theories
> that I realized that there was no issue in favor of COFDM. Instead,
> it's just like those crackpots in the 1980s that were saying we should
> abandon NTSC for PAL.

The reality is that there is no issue in favor of 8-VSB. The Mandate
issued by our FCC is not a conspiracy it is the law. We will have to buy
an 8-VSB receiver if we want to buy a TV set. No choice. In all other
countries that have chosen COFDM receiver sales are high, or very high
or off the charts, no MANDATE is required buy a free people to determine
if they need an OTA receiver of not. 85% of US citizens get their TV
from cable or satellite, they do not need a MANDATED tuner.

The only conspiracy theory that I have suggested is pretty well
documented. It was the workings of the ATSC in lockstep with LG
Industries (Zenith) our FCC, members of Congress and a few terrified
broadcasters. You can read all about it in "Defining Vision" or do a
Google on the subject. Here is a recent statement by someone who was there.

At 9:48 AM -0700 4/8/04, Eory Frank-p22212 wrote:

>>Hey, don't blame ATSC for the fact that technology changes more
rapidly than the ability of standards bodies to keep up and reach
>>consensus on new technologies. Today's ATSC standards do not use the
best available video coding, the best available audio coding, or
>>even the best available RF transmission system.

Craig Birmaier wrote...
Well, I think that they share in the blame for the real world situation
you describe; the blame should also be shared by the Advisory Committee
On Advanced Television Services (ACATS) and the FCC.

The issue of rapid evolution of codecs and other components of the
proposed U.S. DTV system were raised very early on, as was the correct
approach for handling this situation.

The main point of contact for these efforts was via the ACATS process.
In 1992 we were already telling Woiley and the rest of the ACATS
leadership that it would be a big mistake to lock down every component
of the system. At that time, MPEG-2 was just working its way through the
ISO. None of the proposed systems submitted to the ATTC for testing used
MPEG-2. The Sarnoff et al proposal came close using what they were
calling MPEG-1.5 , which included an expanded
tool set relative to MPEG-1. Dolby was in play throughout the ACATS
process, it's main competitor being the audio codec that was eventually
standardized by ISO as part of MPEG-2.

The MAJOR disconnect was between ACATS and the ATSC. ACATS failed
miserably to act as an independent arbiter of the process by which the
standard was created; the ATSC was allowed. even encouraged, to turn
the process into an internal Intellectual Property (IP) shoot-out.

Some here may recall that Wiley and his cronies actively sought the
formation of "The Grand Alliance," on the grounds that there might be
numerous legal challenges to the standard by those who did not get their
IP into the standard. Several months later, the Grand Alliance was
formed and the entire process went underground while the new Grand
Alliance system was built.

I cannot understate the importance of the FACT that all of the companies
with the potential to receive future compensation from the standard were
given unprecedented authority to work together under the auspices of the
advisory committee act, thus insulated from any anti-trust implications.
And further, that the Advisory Committee then rubber stamped everything
that the ATSC developed. There were several shoot-outs, the winners of
which were determined by ACATS.
These shoot-outs included the audio system and the RF system. It comes
as no surprise that the winners were companies that were members of the
Grand Alliance.

It was a common practice for the leadership of the ATSC to have a
pre-meeting with the leadership of ACATS (at Dick Wiley's office) about
a week before each public ACATS meeting. There was significant overlap
in the leadership of both bodies. The agendas for the ACATS meetings
were discussed, and IMHO, the outcomes determined in advance. We were
allowed to provide comments to both ACATS and to the ATSC - I
participated in several ATSC working groups as well as the
Interoperability review of the pre-Grand Alliance systems conducted by
Working Party 4 or ACATS.

The agenda for WP4 was to evaluate the proponent systems with respect to
three criteria discussed many times in this forum:

Interoperability
Scalability
Extensibility

Interoperability involved the compatibility of the proponent systems
with other emerging digital technologies including the personal
computer and the Internet.

Scalability involved the ability of the system to deliver different
Quality of Service Levels - in 1992 the proposed systems were required
to deliver HDTV - any lower level of video quality was specifically "off
the table." The SDTV formats were not added until July of 1995.

Extensibility involved the ability of the system to evolve with the
underlying digital technologies; there was particular emphasis on the
way the system handled audio and video coding and packetized data services.

By 1995 ACATS approved the ATSC standard and the debate moved to the
FCC. having failed to deliver a standard that was
1. Interoperable
2. Scalable
or 3. Extensible

The computer industry and others who were concerned about these issues
filed many comments with the FCC asking them to mandate the absolute
minimal standards for DTV, so that the marketplace could drive the
evolution of the standard. We demonstrated to the FCC that extensibility
was in fact a very achievable goal, and provided reference designs
(functional diagrams) of DTV receivers that would support a high quality
of initial service, AND the ability to add new
capabilities without disenfranchising earlier receivers.

The real irony of all of this is that the ATSC standard is already
dated, and will be completely irrelevant by the time that the analog
spectrum will eventually be returned. The good news is that this will be
obvious to all parties involved, triggering a new debate about the fate
of free-to-air broadcasting.

Regards
Craig


>>By the time tomorrow's ATSC standards are adopted, this will still be
true -- especially with regards to the RF transmission system. I >>agree
that "no broadcaster will adopt E-VSB anyway." One must wonder >>if even
the ATSC will adopt E-VSB, and I'm not saying they should.
>>
>>-- Frank Eory
>
> So, if you think that only places like NYC count, and people who live in
> suburbs and rural areas should put up with the same level of reliability
> you get with cell phones, then you will love COFDM.

Very weird reasoning. First you sugest that COFDM is limited to small
cell size like a cell phone network. WRONG! Then you suggest that the
problems of cell phone reception has to do with the size of their cells
when it has everything to do with the design of their network and the
modulations that cell phones use. And then you transpose all these
arguments over to COFDM, different modulation, a one way system at
infinitely higher power levels (even at low power). And then suggest
that these small cells will somehow have something to do with COFDM
reception and make it like cell phone reception. Ridiculous.

A cell phone is limited by how much power it can broadcast at. Think
about it how much power there is in that little thing you hold up to
your ear. How do you compare that to even a ONE KW DTV transmitter? And
most people think that low power DTV would be anywhere up to 300 kW.

COFDM can have any size cell you want. It can broadcast from a high
tower like 8-VSB at high power and reach the radio horizon with the same
receivablity as 8-VSB. However it will not suffer from dynamic and
static multipath like 8-VSB does in all that coverage area. COFDM does
have the advantage of operating in a lower power cellular structure or
you can mix and match the two. Have an high power transmitter in the
center and low power on-channel repeaters on the edges of the coverage
area. Most of these advantages that COFDM has 8-VSB is trying to
emulate. All the proposed changes to 8-VSB are attempts to copy COFDM.
E-VSB is an attempt to emulate COFDM's mobile capability. 8-VSB is
attempting to do on channel repeaters and an SFN. All these attempts so
far are failures. E-VSB for one cannot do mobile while it sacrifices 5
Mbps of bandwidth and eliminates the possibility that any current 8-VSB
receiver could receive HDTV.
>
> If, on the other hand, you think that TV towers are not going to appear
> all over the landscape, you don't want to wait until a tower is built in
> your neighborhood before you get TV, and you want HDTV (most COFDM is
> not HDTV capable) you would prefer 8VSB.

Tomorrow all 8-VSB transmitters could switch there modulators to COFDM
at their current power levels and more people would be capable of
receiving a DTV signal than yesterday if they had receivers. It is just
that simple. The difference is that with COFDM you have many more
choices. IF there was a problem area with reception or if you wanted to
expand the coverage area with repeaters it is easy with COFDM. You can
do it on channel (the same frequency). With 8-vSB you need a new
frequency and these stations are called translators. There are 5000 of
them in the US. With COFDM you don't need any of them.

ALL OF COFDM IS HDTV CAPABLE. Whether a country choses to implement it
or not is another question. The UK got carried away with COFDM and
implemented an early version before HDTV was written in but any version
any country would adopt today would include the ability to do HDTV.
COFDM towers have already appeared all over the landscape for XMRadio
and Sirius. XM uses 1500 of them and will build more. COFDM is used in
most modern broadcast RF systems such as 802.11 a g and 802.16 and ENG
etc. Do a search for OFDM and COFDM and you will be amazed.
>
> -- Mark --
>
Anonymous
April 11, 2004 10:17:51 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

In article <NW4ec.4595$k05.508@newsread2.news.pas.earthlink.net>,
Bob Miller <robmx@earthlink.net> writes:
> Mark Crispin wrote:
>
>> On Sat, 10 Apr 2004, Nick D wrote:
>>
>>> Is OTA HDTV doomed?
>>> Ive read ALOT of posts about this... some people say OTA HDTV is doomed
>>> because of 8 VSB and that no one is watching it this and that...
>>
>>
>> OTA HDTV is not doomed. What you are reading is a small, disgruntled
>> minority of individuals.
>>
>> Here's what I've been able to put together:
>>
>> The supposed superiority of COFDM only exists in relatively small and
>> quite densely-populated areas. COFDM deployment is much like cell phone
>> deployment: lots of small transmitters to cover a service area. This
>> is, not coincidentally, how TV has traditionally worked in Europe and
>> Japan.
>
> All areas of the world have picked DVB-T COFDM or another version of
> COFDM. COFDM allows for the use of SFN's and on channel repeaters.
>
Of course, the various local zoning (and other kinds of) regulations
make the issue of numerous repeaters quite problematical for the US.
Anecdote: our local area cell coverage is terrible, yet our neighborhood
even voted down a supposedly well hidden cell tower. Ignoring or
begging the issue of the impossibility of installing COFDM repeaters
everywhere in the US (along with the extremely wide areas needed)
shows that person who gives the example has EXTREME bias and ignores
reality.

>
> This
> advantage is one that is being investigated by 8-VSB types.
>
But will only be used in VERY LIMITED circumstances. Depending
upon repeaters (where COFDM derivatives more needy in that area
because of power issues) is a non-starter. There are certainly
cases where repeaters are advantageous, but it is fallacious
to make claims beyond that.

>
> In lab test COFDM was found to have a small power disadvantage.
>
2-3dB is approx double the electricity cost.

>
> THE MAIN point that
> the ATSC of the US kept harping on was the power differential.
>
That is only one of the issues. You seem to have wet dreams
of SFN installations
in the US and ignore the reality of the regulatory/political situation
(e.g. adding many towers just wont happen), and ignore the
real world facts that show that COFDM isn't a panacea (esp in
situations with non-gaussian type noise sources and where there
are strong nearby NTSC transmitters), and ignore the
fact that the US system does work pretty well -- even in the
noise/multipath laden environment in US homes. Part of your
fallacious encouragement against US HDTV is based upon anecdotal
reports of reception failure. Any system can be encouraged to fail,
and sometimes they don't even have to be encouraged all that
much (e.g. moderate impulse noise that is so very common in US
homes.)

A major problem with YOU Bob, is that you advocate COFDM,
while I am interested in the availability of HDTV. HDTV is
of interest to you ONLY because that infrastructure would
provide some ability for your UNIDIRECTIONAL DATA applications.

Don't mistake my advocacy and interest in HDTV with much
interest (other than technical interest as a side-issue) in the
transport methods.
You seem to try to confuse the resistance against your apparent
HDTV destructive business plan with pro/anti COFDM/8VSB
advocacy. I doubt that I could sell out for money by
destroying the newly established HDTV transport, however
there are definitely alot of disgusting lowlifes who
are willing to damage the public good for very selfish
motives. Perhaps you aren't such a bad person, since you
have admitted in the past that 480V is adequate for video
distribution -- and simply discount the value of HDTV.
Of course, this is an HDTV advocacy newsgroup, and you'll
find lots of people who resist your destructive advocacy.


>
> Australia
> dismissed it as INSIGNIFICANT!!!
>
Remember: mobile HDTV is absurd, but SDTV channels filled
with push advertising on mass transit would be a wonderful
cash cow for you?

John
April 11, 2004 3:00:50 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

Here are some comments from current COFDM users in Australia, over the past
12 months or so:
----------------------------------------------------------------------------
---------


-If we get electrical interference (like when the kids flick the switch for
the heater on & off, on & off, on & off...) Not only does the STB flicker
the TV display, but the recorded MPEG file becomes destroyed. If I only get
a little bit of interference then the voice-synch stuffs up.



-Far more artifacts that I would expect.



-the reason it wasn't working on particular channels, was because it was
getting a strong enough signal so all that was on the TV was the screen
telling me to check my antenna connection, as you move it around a bit and
find the signal before it properly locks on it sort of does the freeze frame
thing, where you see a only 1-2 frames per second, plus major pixellisation.
Eventually you find the spot where the signal is strong enough and you get
the generally excellent picture.



-use a mast-head amplifier.



-SD v HD difference is so slight that most people would not be able to tell
the difference. It is practically insignificant.



-Beware the DTV hype.



-I have upgraded to a Digital antenna, with digital grade cable and
splitters.



-Perhaps he means quad shield coax which is recommended for digital which is
prone to electrical impulse interference. And yes, it does make a
difference.



-I used to have to adjust the ears depending on what channel I wanted to
watch, I could never get more than 3/5 main channels at any one time.



-Sometimes it is perfect apart from occasional square/block pixellisation or
split second audio dropouts. These things depend on signal strength, quality
of your aerial/cabling and even weather conditions (in poorer reception
areas).



-I've noticed that with marginal reception, the picture may be good with
static or slow moving images, but when the TV images starting moving quickly
with lots of action, the picture breaks up more..... I would guess that it
is because the reception is adequate for lower bit rates, but is tipped over
the edge with higher bit rates when there is more action. It has become very
apparent that I have lousy reception. Channel 9 is the only station that
works at all om my antenna. As an experiment I dug out some old rabbits ears
and hooked them up to the stb. What I found was with some tweaking I was
able to get all the stations available. The problem was I had to stand on a
chair in a pose like the guy in The Karate Kid to hold the signal and if I
changed channels I had to strike a new pose.



----------------------------------------------------------------------------
----------------

The above remarks are from aus.tv.digital, from one year ago to now.

I counted approximately 400 more remarks like these. When I get more time,
I'll post those too.

But, of course, Miller won't admit this was the COFDM system he was pushing
for in the AVS forum (before he was asked to leave).
Anonymous
April 12, 2004 10:42:50 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

John S. Dyson wrote:

> In article <NW4ec.4595$k05.508@newsread2.news.pas.earthlink.net>,
> Bob Miller <robmx@earthlink.net> writes:

>>
>>All areas of the world have picked DVB-T COFDM or another version of
>>COFDM. COFDM allows for the use of SFN's and on channel repeaters.
>>
>
> Of course, the various local zoning (and other kinds of) regulations
> make the issue of numerous repeaters quite problematical for the US.
> Anecdote: our local area cell coverage is terrible, yet our neighborhood
> even voted down a supposedly well hidden cell tower. Ignoring or
> begging the issue of the impossibility of installing COFDM repeaters
> everywhere in the US (along with the extremely wide areas needed)
> shows that person who gives the example has EXTREME bias and ignores
> reality.

Ignores reality? Your the one who ignores reality. XMRadio and Sirius
were able to install all the repeaters that they wanted. If you look at
XM sites they are all over the cities and suburbs. I can call a tower
company and have three locations for any coverage area I want. COFDM
DOES NOT require a cellular phone type network. A cellular phone network
requires small cell sites because the phone in your hand has to
BROADCAST back to a cell tower.

COFDM has the ADVANTAGE of using small cells when it makes sense. If in
doing that you found an area that you could not get a tower space you
could increase the power of surrounding transmitters a bit to fill in
the area. The reality is that you try to take the advantages of COFDM
and turn them into negatives.
>
>
>>This
>>advantage is one that is being investigated by 8-VSB types.
>>
>
> But will only be used in VERY LIMITED circumstances. Depending
> upon repeaters (where COFDM derivatives more needy in that area
> because of power issues) is a non-starter. There are certainly
> cases where repeaters are advantageous, but it is fallacious
> to make claims beyond that.

30% of the continental US depends on NTSC repeaters today. While there
are 1600 or so full power NTSC TV stations there are 5000 repeaters that
they use on other frequencies because NTSC cannot repeat on the same
channel that they broadcast on. THIS IS NOT A LIMITED circumstance.
>
>
>>In lab test COFDM was found to have a small power disadvantage.
>>
>
> 2-3dB is approx double the electricity cost.

Actually if a network were properly designed with an SFN the total power
requirements can decrease with COFDM by 90%. That would be 10% of
current 8-VSB power requirements. The SFN has built in redundancy and if
one transmitter were to go down it would not impact reception very much
unlike recent events in the US where we have lost many SINGLE
transmitters in tower disasters like New York and the Moscow fire. In
both cases it has been years now with no replacement.

Here is a quote from an article on COFDM and power and frequency efficiency.

"SFNs allow the same frequency to be used for a given area and this
means that a few low power transmitters can be used as opposed to having
one very high power transmitter. Overall, the power required using the
SFN concept is lower for transmitting to a given area. SFNs are also
spectrally efficient when it comes to frequency planning because for
example, both the BBC and Digital One use the same frequency right
across the UK, so the situation where there are multiple frequencies
required is avoided."

http://www.digitalradiotech.co.uk/cofdm.htm
>
>
>>THE MAIN point that
>>the ATSC of the US kept harping on was the power differential.
>>
>
> That is only one of the issues. You seem to have wet dreams
> of SFN installations
> in the US and ignore the reality of the regulatory/political situation
> (e.g. adding many towers just wont happen), and ignore the
> real world facts that show that COFDM isn't a panacea (esp in
> situations with non-gaussian type noise sources and where there
> are strong nearby NTSC transmitters), and ignore the
> fact that the US system does work pretty well -- even in the
> noise/multipath laden environment in US homes.

So you settle for "pretty well" as long as it works for you. If pretty
well didn't include you I wonder what you would be saying.

As was stated before there is no problem politically or regulatory with
towers for the number of transmitters needed for COFDM. A similar COFDM
network was installed in just the last few years by XMRAdio with no
problem. It is not the same as a cellular phone system. The power levels
are far higher. Siting can be over a relatively large area.

Part of your
> fallacious encouragement against US HDTV is based upon anecdotal
> reports of reception failure. Any system can be encouraged to fail,
> and sometimes they don't even have to be encouraged all that
> much (e.g. moderate impulse noise that is so very common in US
> homes.)

I have no argument with HDTV. HDTV is a resolution. I have a problem
with an inadequate modulation, 8-VSB. Both 8-VSB and COFDM can do many
resolutions and COFDM can deliver HDTV to more people for less money and
hassle.

This will become more apparent as Japan and Australia and soon possibly
France are successful with OTA HDTV with COFDM while we will continue to
fail with 8-VSB.

Bob Miller
Anonymous
April 12, 2004 12:25:16 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

In article <Rv3ec.3478$iE.1431@okepread04>, dseaman8@cox.net says...
> That was impressive.
>
> Thanks Chris. Do you have a visual representation of what you just
> explained? Is there a website where I can go to see this stuff? I'm a visual
> learner.

Unfortunately, I don't know of any discussions of 8-VSB that aren't
hightly mathematical in nature. The ATSC standards describe how to
generate a singal, but again this is anything but visual. You can
probably find a lot on SSB (single side band), by searching on "ssb"
with google, but although a VSB signal is a lot like SSB, the
generation process is much different. The reason that analog TV used
VSB was to prevent distortion of the very low frequency components of
the signal (eg, the 60 hz sync pulses). Digital transmission doesn't
have this concern, and 8-VSB is generated differently as a result.

It's not much, but the following has a graphical representation of
VSB at the bottom. Ignore the math:
http://people.deas.harvard.edu~jones/cscie129/lectures/...
ation/modulation_1.html
(sorry about the long URL).

/Chris, AA6SQ

PS. To understand why anything in analog TV is the way that it is,
you have to keep in mind what engineers did and didn't know how to do
ca. 1940 -1945. Today 8-VSB is generated with a couple of integrated
circuit chips with hundreds of thousands of active elements each. In
1940, this would have required a room full of equipment. In
paticular, VSB was accomplished by generating an AM signal, and then
using using a large mechanical filter to remove one sideband. These
filters had to be water cooled.
Anonymous
April 12, 2004 1:42:34 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

On Mon, 12 Apr 2004, Bob Miller wrote:
> Ignores reality? Your the one who ignores reality. XMRadio and Sirius were
> able to install all the repeaters that they wanted. If you look at XM sites
> they are all over the cities and suburbs.

BULLSHIT!

I have XM. In the Seattle area, their terrestrial repeaters are only in
the urban cores. In the residential areas of the city and in the suburbs
there is NO(!!) terrestrial coverage. If you can't get the satellite you
are screwerd.

I have XM installed in my RV. It has been disappointing. It only works
reliably on the large interstates, and even then you get dropouts as soon
as you get into terrain. Which of course Bob wouldn't know about since he
lives in the flat East where they call a 100 foot hill a "mountain".

XM works really well if you have a fixed antenna pointing south. That's
why they give you a nice long antenna wire on the XM boombox -- you'll
need it since you'll want to put the antenna on a south-facing window
which is probably not where you want to boombox.

> I can call a tower company and have
> three locations for any coverage area I want.

In New Yawk City, yes. But in real parts of the country, no.

I am in a location less than 10 miles from Seattle, and two miles from a
smaller city (Bremerton). The TDMA cell carrier shows 2 bars out of 4.
The GSM and CDMA carriers show 1 bar. Around here, you have to "assume
cell phone usage position" and even then you get dropouts.

The reason is TERRAIN and ZONING. There are, and will always be,
inadequate towers for reliable cell phone coverage outside of the urban
core. Every new tower is a major legal battle.

Yet, most 8VSB DTV channels work quite well here. The two exceptions have
directional transmitting antennas that don't send any signal here. There
is nothing that COFDM can do to fix that.

> The SFN has built in redundancy and if one
> transmitter were to go down it would not impact reception very much unlike
> recent events in the US where we have lost many SINGLE transmitters in tower
> disasters like New York and the Moscow fire. In both cases it has been years
> now with no replacement.

NOBODY outside of New Yawk City cares about TV in New Yawk City. You may
think that NYC is the center of the universe. It is not.

> "SFNs allow the same frequency to be used for a given area and this means
> that a few low power transmitters can be used as opposed to having one very
> high power transmitter. Overall, the power required using the SFN concept is
> lower for transmitting to a given area.

That is because COFDM has such high power requirements you are forced to
use SFN to have affordable coverage. 8VSB doesn't have that problem.

> So you settle for "pretty well" as long as it works for you.

No, it is "pretty well" if it works for most of the people in the country.

> As was stated before there is no problem politically or regulatory with
> towers for the number of transmitters needed for COFDM. A similar COFDM
> network was installed in just the last few years by XMRAdio with no problem.

Why don't you visit Seattle. I will drive you around the urbanized
Seattle metropolitan area. Every time there is a terrestrial coverage
dropout, I get to tap you on your head with my crowbar. Everytime there
is a complete signal dropout, I get to whack you on your head with
crowbar.

After just a few minutes, I will have rearranged enough of your brain
cells that you may have acquired understanding.

The Seattle experience with XM is not unique. I have contacts throughout
the country and their experience is much the same.

> I have no argument with HDTV. HDTV is a resolution. I have a problem with an
> inadequate modulation, 8-VSB. Both 8-VSB and COFDM can do many resolutions
> and COFDM can deliver HDTV to more people for less money and hassle.

COFDM will not happen in North America. The more that you rant, the more
determimed people are to prevent COFDM. You've made COFDM into a crackpot
cause.

I've seen your company's web page. A SWF animation and a mailto link to
you. That's all your company is. You're blaming 8VSB for your company's
failure. The real cause is that your company is vapor.

> This will become more apparent as Japan and Australia and soon possibly
> France are successful with OTA HDTV with COFDM while we will continue to fail
> with 8-VSB.

Conditions in the population centers of Japan and Australia are nothing
like North America. And Japan uses its own incompatible form of COFDM
since the one used in Europe and Australia didn't work.

But that begs the question: why should we care what foreign countries do?

-- Mark --

http://staff.washington.edu/mrc
Science does not emerge from voting, party politics, or public debate.
Si vis pacem, para bellum.
Anonymous
April 12, 2004 11:40:29 PM

Archived from groups: alt.tv.tech.hdtv (More info?)

On Mon, 12 Apr 2004, Matthew L. Martin wrote:
> Yes, virtually everything bob says is bullshit. Your real world experience
> will get the same response from bob that all of the posts about successful
> reception of ATSC where NTSC fails: none.

In fact, I agree, ATSC kicks NTSC butt. It is difficult, if not
impossible, to get a viewable picture OTA with NTSC around here, except on
the smallest portable TVs. Ghosting and interference is terrible, even
with a directional rooftop antenna. Even Fox, which has a clear line of
sight to me, comes in with ghosting.

If ATSC was so vulnerable to multipath, I'd expect ATSC to be unusable
here. But it isn't. As long as the transmitter site sends a signal my
way, I'll get it and get a nice clear picture.

-- Mark --

http://staff.washington.edu/mrc
Science does not emerge from voting, party politics, or public debate.
Si vis pacem, para bellum.
Anonymous
April 13, 2004 3:37:51 AM

Archived from groups: alt.tv.tech.hdtv (More info?)

Mark Crispin wrote:
> On Mon, 12 Apr 2004, Bob Miller wrote:
>
>> Ignores reality? Your the one who ignores reality. XMRadio and Sirius
>> were able to install all the repeaters that they wanted. If you look
>> at XM sites they are all over the cities and suburbs.
>
>
> BULLSHIT!
>

Yes, virtually everything bob says is bullshit. Your real world
experience will get the same response from bob that all of the posts
about successful reception of ATSC where NTSC fails: none.

Matthew

--

If the war in Iraq was over oil, we lost.
December 23, 2010 12:35:41 AM

COFDM is a disaster as system in particular the ISDB and DVB system, we in Chile the system that we picked the Brazilean Japanese system of DTV works very bad, with indoors antennas and in remote areas just gets pixellation,get the channels lost and is impossible of watch the image, also is not resistant to the impulsive electric noise like the caused by electric motors , there can be the major pixellation, break and no signal not matter where you locate the antenna.

ATSC in the city of Santiago, worked very good, in the trial period before government decide what system we would use.

also is not resistant to multipath issues, the system if somebody pass near by the antenna the signal gets pixellated and breaks.

Frank

!