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Progressive signal to TV

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Anonymous
April 7, 2002 2:19:22 PM

In order to get a progressive signal on your TV (480p) when playing a DVD, does the PC DVD player need to be a (special) progressive DVD player? or Is there a software / graphics card feature that allows a progressive display?

I currently have a RealMagic Holloywood plus card with a run of the mill PC DVD player but I'm not sure whether I am watching a progressive signal or not.

Can anybody help shed some light?

More about : progressive signal

Anonymous
April 8, 2002 9:59:03 PM

in order to display a progressive scan signal (480p) on a tv, the tv must be able to handle a 480p signal through component inputs. most analog sets cannot process 480p, only 480i, even though they pass through component cables. most hdtv that can display 1080i also display 480p, and sometimes even 720p, it varies. the dvdrom in ur computer is played in progressive scan, because thats how your crt monitor draws. if you want to get it on your tv @ 480p, u NEED a digital tv capable of processing 480p via component cables or vga input. if your trying to setup a htpc and you have an hdtv set, you may consider getting a transcoder to adapt vga to component signal at 480p. with ur hollywood card, the best you can output is 480i with an svideo cable, not the best, but thats what ur card can do. the new XCARD that came out by sigma designs can output 480p via component cables, but, it must be hooked upto a 480p input, again, an input youll find on a digital tv, not analog.

hope this helps
Anonymous
April 8, 2002 11:06:09 PM

Thanks for the reply, I should have stated that I do have an HDTV ready set. As a matter of fact it has a VGA input which my Real Majic Hollywood card is connected directly to.

So, if I have interpreted your reply correctly then I must already be viewing a progressive signal via my RealMajic Hollywood plus card. Correct?
Related resources
Anonymous
April 8, 2002 11:22:11 PM

well, lets say u dont have a real magic card. the vga cable out of ur box goes str8 to ur crt monitor. when u watch a dvd player from ur box, u see it on ur monitor in progressive scan. if u use the hollywood card now, and link an rca cable or svideo cable out of it to ur tv, it is not progressive, its interlaced (480i).
what kind of tv do you have would better help me out. most sets do not have a vga input, espically analog sets.
Anonymous
April 8, 2002 11:31:53 PM

I have a Philips 60pp9601 (which comes with a VGA input). It is an HDTV ready set.

I use a pass through cable from my video card to my Real Majic Hollywood card and run the Real Majic card directly to my set via a VGA cable. So, in effect I am using my TV as a computer monitor.

From what I gather from your previous messages, I can assume that when I am in VGA mode on my television that I am viewing a progressive signal. Sound right?
Anonymous
April 8, 2002 11:47:20 PM

good question, and the answer is, im not a 100% sure. i believe the signal is progressive because in vga, as vga is a progressive signal. you main video card outputs progressive, and the hollywood card should passthrough progressive though vga. that is, ur setup is vga from main video card, to vga in on hollywood, to vga out of hollywood into vga in of hdtv...right? another question i want to ask is what do u on ur computer that makes you want to hook to up to ur hdtv? just a bigger screen for whatever, or a bigger screen for dvd movies? if ur main goal is to watch movies, let me know, theres a better way about going about this. i mentioned a transcoder in a previouw msg, which is a better solution. vga ia fixed resolution, vga signal through a transcoder into component inputs is not :) 
let me know
Anonymous
April 9, 2002 2:30:29 AM

To answer your first question, I used the vga out from the hollywood card directly to my tv simply because I had a vga input on my tv (convenience factor I guess).

On your second question, I like the idea of moving to a complete htpc solution. With the right HDTV tuner card I will be able to eliminate several components (i.e. cable box, VCR, and DVD player) and have the added benefit of surfing the net, playing games, and listening to music (mp3 files) all through one component (my PC).

When you refer to a transcoder are you referring to a box that takes vga in and outputs to YPbPr. If so, I happen to have one. I run the vga out from my DVDO line doubler into the converter box (vga to YPbPr) and go from there to my receiver (component in).

What additional resolution would I get over vga by using the transcoder?

Peter
Anonymous
April 9, 2002 2:42:25 AM

well, your not locked in at 640x480, every time has different timings and work best at X resolution, its trial and error. but ive done a fair amount of research, and u can get some a sweet picture going on with the right hardware and software combination. i wish i could get an hdtv myself and mess around with this, but i dont have the bucks to do it. if your looking for more nfo on setting a htpc and what stuff u need, check out http://www.avsforum.com/, by far the best resource ive seen on a/v gear. sign up for a free account, and check out the htpc section, its got alot of great nfo by some knowledgeable folks. lemme know if u need more nfo
Anonymous
April 9, 2002 11:43:33 AM

Thanks for all the info. I'll be sure to check out avsforum.com.

Peter
April 9, 2002 2:07:19 PM

Quote:
it must be hooked upto a 480p input, again, an input youll find on a digital tv, not analog.

The component input for 480p/1080i is ANALOG. The "D" in HDTV is Definition, NOT digital.

Calling the hardware (the TV set) a digital TV is a load of marketing BS just like the digial speakers and headphones.

Tom.
Anonymous
April 9, 2002 5:33:34 PM

wow, all these years i thought it was HIGH DIGITAL TV, and not HIGH DEFINITION TV. you just saved me man, i might have embarrased myself further.

yes, ur correct, 480p and 1080i inputs are ANALOG, but its called a digital tv becuase it has the capability to recieve a digital signal, display the signal in high definition (ie much better than standard definition on an analog set), and do so with all necessary hardware built in (ie hd tuner and decoder built in). whether u like the terminology or not, thats what it is, and please, if you have beneficial and pertinent information to the conversation, plz post it, otherwise keep it to yourself.
Anonymous
April 9, 2002 6:03:08 PM

mind flux,

I just wanted to let you know that I visited AVS forum. Wow! What an incredible source for HTPC solutions. A lot of questions I had are now answered. Thanks so much for the info. Much appreciated.

Peter
Anonymous
April 9, 2002 6:07:29 PM

np :) 
enjoy
April 15, 2002 11:38:25 PM

<i>HDTV -</i>
High-Definition TV in digitized formats that will eventually replace present analog formats in 16:9 wide-screen TV.
The Japanese version of HDTV is not truly the fully-digitized version broadcast system intended for the US.

<i>Terms-Federal Standard 1037C - HDTV -</i>
Television that has approximately twice the horizontal & twice the vertical emitted resolution specified by the NTSC standard.
In HDTV, the total number of pixels is therefore approximately 4 times that of the NTSC standard.
HDTV may include any or all improved-definition television (IDTV) & extended-television (EDTV) improvements.
HDTV employs a wide aspect ratio.



if <b>you know</b> <font color=white>you don't know<i><font color=black>, the way could be more easy ...<font color=red>
April 16, 2002 8:11:10 PM

Once and for all:

HDTV is an ANALOG display format. It is not even a TV standard - it is a standard for the "monitor" (or display/screen) that is used and the signal driving the monitor. Think of it like VGA/SVGA/XGA, etc. There are NO consumer televisions available that receive a digital signal. The only consumer screens I know of that accept a digital signal are high-end LCD panels.

To clarify:
1) The signal travelling down your VGA cable to your PC monitor is ANALOG.
2) The signal travelling down your VGA cable to your HDTV is ANALOG.
3) The signal travelling down your Composite/S-Video/Component Video Cable is ANALOG.

Digital TV (DTV), on the other hand, is a standard(s) for delivering broadcast signals over the airwaves to a "standard" TV antenna that are then delivered to your Digital TV tuner. This signal is no different in its content (except its modulation, etc.) than the digital cable or digital satelite signal received by millions already, except that the signal is free (unless you live in the UK). That signal is then decoded into *gasp* an ANALOG signal to be delivered to your NTSC/PAL/SECAM or HDTV "monitor." This is the case whether you have an HDTV "ready" set or an HDTV set with the DTV tuner already installed.

i/p480, i/p720, i/p1080, etc. are ALL analog formats. If you have a satelite or cable tuner (or PC) that can output one of these signals (853x480, 1280x720, 1920x1080, etc.) using VGA or Component Video outputs, you already have an HDTV output.

The only reason that HDTV and DTV are often confused is that legally they are tied together - the broadcast stations in the US are required to broadcast in the HDTV formats if they want to keep their DTV bandwidth. They originally wanted to keep broadcasting in NTSC, etc. which would have given them ~8x the bandwidth for channels, but the FCC told them it would yank the extra bandwidth back if they went forward with that plan. They now have until ~2008, IIRC, to get all signals converted to HDTV display format over DTV broadcast signals.

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
April 16, 2002 10:10:15 PM

- is HDTV a format ? -
The 1125-, 1080-, 1035-line interlace & 720 & 1080-line progressive formats in a 16:9 aspect ratio.
Officially a format is high definition if it has at least twice the horizontal & vertical resolution of the standard signal being used.
There is a debate as to whether 480-line progressive is also high definition. It is the opinion of the editors that 480-line progressive is not an HDTV format, but does provide better resolution than 480-line interlace, making it enhanced definition format.


Quote:
HDTV is an ANALOG display format

Because of the larger picture size (16:9 display ratio for HDTV vs 4:3 for regular TV) & more horizontal picture lines, HDTV has a higher quality display than conventional TV. Also, HDTV has cd-quality sound & involves digital transmission instead of analog.
<A HREF="http://www.wral.com/wralinfo/623644/detail.html" target="_new">WRAL-TV 5</A> in Raleigh, NC, is the first television station in the nation to apply for an HDTV license.


if <b>you know</b> <font color=white>you don't know<i><font color=black>, the way could be more easy ...<font color=red><P ID="edit"><FONT SIZE=-1><EM>Edited by Labdog on 04/16/02 06:21 PM.</EM></FONT></P>
April 17, 2002 2:41:55 AM

Quote:
There is a debate as to whether 480-line progressive is also high definition. It is the opinion of the editors that 480-line progressive is not an HDTV format, but does provide better resolution than 480-line interlace, making it enhanced definition format.

While this is my opinion as well, many of the broadcasts from the major networks advertised as "HDTV" are actually shown in 480i or 480p. These two formats were added to the HDTV display spec temporarily.

Quote:
Because of the larger picture size (16:9 display ratio for HDTV vs 4:3 for regular TV) & more horizontal picture lines, HDTV has a higher quality display than conventional TV. Also, HDTV has cd-quality sound & involves digital transmission instead of analog.

If you look at HDTV as the over-arching standard that includes the display formats, the sound formats, and the trasmission signal format, you are correct. But, the actual over-air transmission formats are called Digital TV (DTV). Different countries have different DTV standards. Different satelite and cable companies have different DTV standards. Unlike NTSC/PAL/SECAM, the HDTV display standards are all the same - it is the DTV portion that is different. The image from the DTV decoder is converted to analog before being passed to the HDTV display circuitry. The sound is passed through a surround sound decoder before being passed as an analog signal to the amplifier.

My point is simply that HDTV display formats and the driving signals are analog - not digital.

Quote:
WRAL-TV 5 in Raleigh, NC, is the first television station in the nation to apply for an HDTV license.

Actually, that would be a "DTV license" for <A HREF="http://ftp.fcc.gov/oet/dtv/" target="_new">FCC</A> purposes. If you read the "TV 5" link further you will notice that they talk about broadcasting in "HDTV format." For the sake of consumers, television stations generally refer to their DTV broadcasts as "HDTV" because the display format they are broadcasting is generally an HDTV format - because the FCC requires them to. There is no technical requirement for DTV (the digital part) signals to be HDTV compliant. As a matter of fact, some DTV signals contain NTSC formated broadcasts. HDTV signals received over cable or satelite are transmitted using DVB signalling, not over-air DTV, yet they also are output by the satelite receiver as an analog component video signal to the HDTV compliant display and are called "HDTV."

My overhead projector with 110" drop screen (96 x 54) accurately displays up to 1080p images, yet it outputs no sound, and the signal sent to my projector is a 1080p HDTV analog component video signal. This is still HDTV display. My stereo system handles the digital sound and my satelite receiver handles the digital tv signal.

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
April 20, 2002 12:09:04 AM

HDTV Television - An Introduction

EE 498
Professor Kelin J. Kuhn


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

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

Two lectures of material



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I. The movement toward HDTV


The original impetus for HDTV came from wide-screen movies. Soon after wide-screen was introduced, movie producers discovered that individuals seated in the first few rows enjoyed a level of participation in the action not possible with conventional movies. Evidently, having the screen occupy a great field of view (especially peripherally) significantly increases the sense of "being there".


Early in the 1980s, movie producers were offered a high-definition television system developed by Sony and NHK in the late 70s. This system (called NHK Hi-vision) and its variants are capable of producing images having essentially the same detail as 35 mm film[1]. With these systems, a scene could be recorded, played and edited immediately, and then transferred to film. As a consequence, many of the intermediate delays in conventional film production were eliminated. The new medium also offered a number of possibilities for special effects not possible in conventional film production.


Following the introduction of HDTV to the film industry, interest began to build in developing an HDTV system for commercial broadcasting. Such a system would have roughly double the number of vertical lines and horizontal lines when compared to conventional systems.


Now, the most significant problem faced with HDTV is exactly the same problem faced with color TV in 1954. There are approximately 600 million television sets in the world and approximately 70% of them are color TVs. An important and critical consideration is whether the new HDTV standard should be compatible with the existing color TV standards, supplant the existing standards, or be simultaneously broadcast with the existing standards (with the understanding that the existing standards would be faded out over time).


There is precedence for both compatibility and simultaneous broadcast. In 1957, the US chose compatibility when developing the color TV standard. Although there were some minor carrier interference problems due to the additional chrominance signal -- to a large extent, both monochrome and color TVs could read the same signal.


As a example of simultaneous broadcast, consider Britain. Monochrome broadcast began in Britain in 1936 with a 405 line standard. In 1967, the 625 line PAL color standard was introduced. The color and monochrome standards then operated in parallel for fifty years. In 1986, when the 405 line service was terminated, so few 405 line monochrome monitors remained that it was seriously considered that Parliament simply purchase 625 line monitors for the remaining 405 line users, as that was considerably cheaper than maintaining the 405 line service. (This amusing idea did not happen however, due to possible political repercussions!)



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

II. Basic ideas for HDTV


The basic concept behind high-definition television is actually not to increase the definition per unit area ... but rather to increase the percentage of the visual field contained by the image.


The majority of proposed analog and digital HDTV systems are working toward approximately a 100% increase in the number of horizontal and vertical pixels. (Proposals are roughly 1 MB per frame with roughly 1000 lines by 1000 horizontal points). This typically results in a factor of 2-3 improvement in the angle of the vertical and horizontal fields. The majority of HDTV proposals also change the aspect ratio to 16/9 from 4/3 -- making the image more "movie-like".


The following table summarizes a few of the more conventional analog HDTV proposals in comparison with existing TV systems[2]. (Note Grand Alliance and other fully digital proposals are not included in this table.)


Name Prog. Total Active Vert. Horz. Opt. Asp. Vert. Horz. freq.
or lines lines res. res. view ratio field field MHz
inter. dist.
HDTV p 1050 960 675 600 2.5H 16/9 23 deg 41 deg 8
USA,
analog
HDTV p 1250 1000 700 700 2.4 16/9 23 deg 41 deg 9
Europe,
analog
HDTV NHK i 1125 1080 540 600 3.3 16/9 17 deg 30 deg 20
NTSC i 525 484 242 330 7 4/3 8 deg 11 deg 4.2
conv.
NTSC p 525 484 340 330 5 4/3 12 deg 16 deg 4.2
prog.
PAL i 625 575 290 425 6 4/3 10 deg 13 deg 5.5
conv.
PAL prog p 625 575 400 425 4.3 4/3 13 deg 18 deg 5.5
SECAM i 625 575 290 465 6 4/3 10 deg 13 deg 6
conv.
SECAM p 625 575 400 465 4.3 4/3 13 deg 18 deg 6
prog


NOTE: The aspect ratio of the picture is defined to be the ratio of the picture width W to its height H. The optimal viewing distance (expressed in picture heights, H) is the distance at which the eye can just perceive the detail elements in the picture.


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

III. Issues in HDTV


A. Bandwidth limitations


A best, one cycle of an analog video frequency can provide information to two pixels. (NOTE: This is AT BEST -- it can easily be argued that one cycle only provides full video information to one pixel!)


A conventional NTSC image has 525 lines scanned at 29.97 Hz with a horizontal resolution of 427 pixels. This gives 3.35 MHz (assuming 2 pixels per video cycle) as a minimum bandwidth to carry the video information without compression.


If one decides to move to an HDTV image that is 1050 lines by 600 pixels (keeping the same frame rate), then this means a bandwidth of 18 MHz. Clearly we have a problem here -- as the current terrestrial channel allocations are limited to 6 MHz!


(As an aside, the word "terrestrial" as used by TV people means conventional wireless TV transmission. This is to differentiate it from satellite or cable.)


The options for terrestrial broadcast (assuming a 20 MHz bandwidth) are roughly as follows:


1. Change the channel allocation system from 6 MHz to 20 MHz.

2. Compress the signal to fit inside the 6 MHz existing bandwidths

3. Allocate multiple channels (2 with compression or three without) for the HDTV signal


Options 1 and 2 are virtually incompatible with current NTSC service. About the only possibility for maintaining compatibility is simultaneous broadcast of NTSC information over certain channels and HDTV information over other channels.


Option 3 does allow compatibility -- as the first 6 MHz of the signal could keep to the standard NTSC broadcasting and the remaining be additional augmentation signal for HDTV. Typically, in this type of augmentation system, an existing VHF channel would be tied to one (or two) UHF channels. The VHF channel would carry information similar to the current NTSC signal and the UHF channel (or channels would carry augmented high resolution information).


B. Distribution -- terrestrial? satellite? cable?


Advocates for HDTV systems fall into two major categories. There are those that feel that these systems will ultimately be successful outside the conventional channels of terrestrial broadcasting. Equally vehemently, are those that think HDTV can and must use existing terrestrial broadcast channels.


NTSC terrestrial broadcast channels are essentially 6 MHz wide. Service in a given area (roughly a 50 mile circle around the broadcast station) is typically offered on every other channel in order to avoid interference effects. A relatively small range of channels are available (channels 2-69, 55-88, 174-216, 470-806 MHz).


In 1987, the FCC issued a ruling indicating that the HDTV standards to be issued would be compatible with existing NTSC service, and would be confined to the existing VHF and UHF frequency bands.


In 1990, the FCC announced that HDTV would be simultaneously broadcast (rather than augmented) and that its preference would be for a full HDTV standard (rather than the reduced resolution EDTV).


These two decisions are very interesting, as they are almost contradictory. The 1987 decision is clearly leaning toward a augmentation type format -- where the NTSC service continues intact and new channels provide HDTV augmentation to the existing. The 1990 decision is a radical and non-conservative approach -- one which basically removes the requirement for compatibility by allowing different HDTV and NTSC standards to exist simultaneously for a period of years. Then the NTSC is gradually faded out as the HDTV takes over.


Now, the FCC does not have jurisdiction over channel allocation in cable networks. Thus, there is the rather interesting question of what the cable TV companies will do. They have a number of interesting options. They can continue to broadcast conventional NTSC, they can install 20 MHz MUSE-type HDTV systems (or other types of HDTV systems), or they can go with the digital Grand Alliance systems. This presents the interesting possibility of two different HDTV standards, one for terrestrial broadcast and one for cable broadcast.


C. Interlaced versus non-interlaced.


The maximum vertical resolution promised by a particular TV system is greater than the actual observed resolution. The reduction in resolution is due to the possibility of a picture element (pixel) falling "in-between" the scanning lines. Measurement gives a effective resolution of about 70% of the maximum resolution (the Kell factor) for progressively scanned (i.e. not interlaced) systems. If the image is interlaced, then the 70% factor only applies if the image is completely stationary. For non-stationary interlaced images this resolution falls to about 50%.


Interlacing also produces serrated edges to moving objects, as well as flicker along horizontal edges (glitter) and misaligned frames. As a consequence of the many problems associated with interlacing, a number of the HDTV proposals are for progressively scanned (not interlaced) service. Notice that these apply both to new ideas for HDTV, and to upgrades of the existing NTSC, PAL and SECAM systems as well. (Although initiating progressive scanning on conventional service does create compatibility problems, some of these techniques offer improved performance to NTSC/PAL/SECAM without the associated problems of moving to "true" HDTV.)


D. Compression


Even if extra channel space is available -- it is usually not enough for the very wide bandwidths of HDTV. As an example, the current NHK satellite broadcast system in Japan (the only "in-service" HDTV system) requires 20 MHz, but only has 8.15 MHz available per channel from direct satellite broadcast.


Thus, some type of compression is typically required. Interestingly enough, although these compression schemes result in analog signals -- they are digitally implemented. Thus, the line between "digital" and "analog" HDTV begins to blur.


1. Signal compression in the MUSE system


The MUSE currently used for satellite HDTV service in Japan is a modification of the NHK HDTV standard for direct broadcast satellite service. The wide bandwidth of the NHK HDTV system is too large for the 8.15 DBS service. As a consequence, the signal must be compressed.


The NHK HDTV signal is initially sampled at 48.6 Ms/s. This signal controls two filters, one responsive to stationary parts of the image -- one responsive to moving parts. The outputs of the two filters are combined and then sampled at the sub-Nyquist frequency of 16.2 MHz. The resulting pulse train is then converted by to analog with a base frequency of 8.1 MHz[3].

<A HREF="http://www.ee.washington.edu/conselec/CE/kuhn/hdtv/95x5..." target="_new">graph</A>



What is happening here is that the subsampling results in successive transmission of signals representing every third picture element. Thus, three adjacent picture elements in the receiver actually represent three successive scans of the same line. Stationary objects are not bothered by this, and appear at their full resolution. However, moving objects do not reoccur in their proper positions and create a smearing effect. This is not a real problem with moving objects in the scene (as the human eye is not very sensitive to this either). However, it does present a problem during camera panning, where the overall image suffers about a 50% drop in resolution -- while the human eye does not.


2. Signal compression in the MAC system


The MAC system was originally proposed as the analog compression standard for European HDTV. Under the original plans, HDTV broadcasts using MAC would be standard in 1995. However, for a variety of reasons, MAC did not make it in Europe[4]. In fact, MAC has died so hard that Europe may simply wait until the US develops an all digital HDTV standard and then use a 50 Hz modified version of it. (As an aside, an interesting situation occurs with European HDTV systems. The peripheral vision is much more sensitive to contrast and movement than foveal vision. As a consequence, the 50 Hz field rate (25 Hz frame rate) has been found to be too slow. The edges of a 50 Hz HDTV image will flicker. Thus, most European HDTV systems advocate 100 Hz.)


However, in spite of the political death of MAC, the technological aspects of the compression are very interesting and worth knowing about. Basically the MAC (multiplexed analog components) compression system fits the luminance and chrominance information into the horizontal line scan in a sequential way. In other words, the R-Y information is sent on one scan, and the B-Y on the next scan.


The color difference and luminance information is sent in a time multiplexed fashion. Looking at the signal in time, the first part of the signal is audio information, followed by chrominance (R-Y or B-Y), followed by luminance[5].


<A HREF="http://www.ee.washington.edu/conselec/CE/kuhn/hdtv/95x5..." target="_new">graph</A>


In order to get the signal into this form require some serious digital processing. Initially, the luminance, R-Y and B-Y signals are sampled and stored digitally. The luminance is sampled at 13.5 MHz and the color difference signals at 6.75 MHz. Then a 3/2 compression on the luminance and a 3/1 compression on the chrominance is performed.


Now, the three signals are read out to produce pulse trains, and then back converted into analog form. The time compression resulting from this operation allows them to be time domain multiplexed in order to fit within the 64 uS horizontal scan time.




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

IV. MUSE -- or how the Japanese have gone toward HDTV


As of today, Japan is the only country actually broadcasting HDTV services. Approximately 30,000 receivers and 100,000 converters have been sold to customers of this service[6]. It is widely believed that the establishment of this analog broadcast service essentially eliminates the possibility of starting a digital satellite HDTV service in Japan.


The history of this begins in 1968, when Japan's NHK began a massive project to develop a new TV standard. This 1125 line system, is an analog system which uses digital compression techniques. It is a satellite broadcast system which is not compatible with current Japanese NTSC terrestrial broadcast. (This actually makes a lot of sense for Japan, as they are a single group of islands easily accessed by one or two satellites).


The MUSE system as originally developed by NHK was a 1125 line, interlaced, 60 Hz, system with a 5/3 aspect ratio and an optimal viewing distance of roughly 3.3H. The pre-compression bandwidth for Y is 20 MHz, and the pre-compression bandwidth for chrominance was 7 MHz. As time has passed, this standard has been altered and upgraded.


The various standard MUSEs are summarized below[7].


lines per field rate Y C C aspect
frame bandwidth bandwidth bandwidth ratio
- wide - narrow
NHK-1980 1125 lines 60 Hz 20 MHz 7 MHz 5.5 MHz 5/3
MUSE 1986 1125 lines 60 Hz 20 MHz 6.5 MHz 5.5 MHz 5/3
SMPTE 1125 lines 60 Hz 30 MHz 30 MHz 30 MHz 16/9
1987
(studio)


In considering how to broadcast this signal, Japanese engineering immediately rejected conventional vestigial sideband broadcasting (i.e. broadcasting methods similar to NTSC). They immediately jumped to the idea of using satellite broadcast (no doubt helped by the geography of the Japanese Islands, which economically support satellite broadcast.)


The Japanese initially explored the idea of FM modulation of a conventionally constructed composite signal. (This would be a signal similar in structure to the Y/C NTSC signal - with the Y at the lower frequencies and the C above.) Approximately 3 kW of power would be required, in order to get 40 dB of signal to noise for a composite FM signal in the 22 GHz satellite band[8]. This was virtually incompatible with satellite broadcast!


So, the next idea was to use separate transmission of Y and C. This drops the effective frequency range and dramatically reduces the required power. Approximately 570 W of power (360 for Y and 210 for C) would be required in order to get 40 dB of signal to noise for a separate Y/C FM signal in the 22 GHz satellite band[9]. This is much more feasible!


There is one more power saving that appears from the character of the human eye. Lack of visual response to low frequency noise allows significant reduction in transponder power if the higher video frequencies are emphasized prior to modulation at the transmitter and de-emphasized at the receiver. This method was adopted, with crossover frequencies for the emphasis/de-emphasis at 5.2 MHz for Y and 1.6 MHz for C. With this in place, the power requirements drop to 260 W of power (190 for Y and 69 for C)[10].


As mentioned earlier (see the section on compression) -- the problem of fitting the combination Y/C signal into the 8.15 MHz satellite bandwidth was solved by digital compression. Summarizing the previous discussion, the NHK HDTV signal is initially digitally sampled at 48.6 Ms/s. This signal controls two filters, one responsive to stationary parts of the image -- one responsive to moving parts. The outputs of the two filters are combined and then sampled at the sub-Nyquist frequency of 16.2 MHz. The resulting pulse train is then converted by to analog with a base frequency of 8.1 MHz[11].




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

V. The Grand Alliance -- all digital HDTV and where the US is going from here


A. History:


In 1987, the FCC issued a ruling indicating that the HDTV standards to be issued would be compatible with existing NTSC service, and would be confined to the existing VHF and UHF frequency bands.


By the end of 1988, the FCC had received 23 different proposals for HDTV or EDTV standards. These were all analog (or mixed analog/digital systems like MUSE) and explored a variety of different options for resolution, interlace and bandwidth.


In 1990, the FCC announced that HDTV would be simultaneously broadcast (rather than augmented) and that its preference would be for a full HDTV standard (rather than the reduced resolution EDTV).


On May 31, 1990 General Instrument Corp. submitted the first proposal for an all digital HDTV system. By December 1990, ATRC announced its digital entry, followed quickly by Zenith and AT&T, then MIT. Thus there were four serious contenders for digital HDTV, as well as a modified "narrow" MUSE and an EDTV proposal. During the following year, these systems were tested.


In February 1993, the FCC made the key decision for an all digital technology -- but could not decide among the four contenders. Therefore, after some fuss, a recommendation was made to form a "Grand Alliance" composed of AT&T, GI, MIT, Philips, Sarnoff, Thomson and Zenith. This Grand Alliance would take the best features of the four systems and develop them into an HDTV standard. Most of the remainder of 1993 was devoted to establishing the features of this new standard.


During 1994, the system was constructed and 1995 is slated for testing. If all goes well, the FCC may be setting this standard by the end of 1995.


B. The basic standard


The Grand Alliance standard differs from all existing TV standards in three major ways. First, it is all digital standard -- to be broadcast with a packet transmission. Second, it supports multiple formats. Third, it is designed to be primarily compatible with computers rather than existing NTSC televisions.


Summarizing the various formats[12].


active lines active aspect ratio frame rate in
horizontal Hz*
pixels
720 1280 16/9 progressive 24, 30 or 60
1080 1920 16/9 interlaced 60
1080 1920 16/9 progressive 24, 30


* Spectrum reports that "all the formats are supported with NTSC frame rates, 59.94Hz, 23.97 Hz, and 29.97 Hz."

C. Compression


The compression algorithms use both a motion compensated and discrete cosine transform (DCT) algorithm. The motion compensation exploits temporal redundancy. The DCT exploits spatial redundancy. MPEG-2 syntax will be used -- because it is already well established, will aid in world-wide acceptance, and will smooth the road to computer and multimedia compatibility. Audio will be supported by Dolby AC-3 digital audio compression. This will include full surround sound.


The core of the Grand Alliance concept is a switched packet system. Each packet contains a 4-byte header, and a 184 byte data word. Each packet contains either video, audio, or auxiliary information. For synchronization, the program clock reference in the transport stream contains a common time base. For lip sync between audio and video, the streams carry presentation time stamps that instruct the decoder when the information occurs relative to the program clock[13].

<A HREF="http://www.ee.washington.edu/conselec/CE/kuhn/hdtv/95x5..." target="_new">graph</A>



The terrestrial transmission system is a 8-level vestigial sideband (VSB) technique. The 8-level signal is derived from a 4-level AM VSB and then trellis coding is used to turn the 4-level signals into 8-level signals. Additionally, the input data is modified by a pseudo-random scrambling sequence which flattens the overall spectrum. Cable transmission is by a 16-level VSB technique without trellis coding.


Finally, a small pilot carrier is added (rather than the totally suppressed carrier as is usual in VSB). This pilot carrier is placed so as to minimize interference with existing NSTC service[14].


<A HREF="http://www.ee.washington.edu/conselec/CE/kuhn/hdtv/95x5..." target="_new">graph</A>


The Grand Alliance system is clearly designed with future computer and multimedia applications in mind. The use of MPEG-2 will permit HDTV to interact with computer multimedia applications directly. For example, HDTV could be recorded on a multimedia computer, and CD/ROM applications could be played on HDTV systems.


<A HREF="http://www.ee.washington.edu/conselec/CE/kuhn/hdtv/95x5..." target="_new">here this link</A>


if <b>you know</b> <font color=white>you don't know<i><font color=black>, the way could be more easy ...<font color=red><P ID="edit"><FONT SIZE=-1><EM>Edited by Labdog on 04/19/02 08:10 PM.</EM></FONT></P>
April 20, 2002 1:52:31 AM

FYI <A HREF="http://www.mlesat.com/tutorial.html" target="_new">the digital satellite TV</A>


if <b>you know</b> <font color=white>you don't know<i><font color=black>, the way could be more easy ...<font color=red><P ID="edit"><FONT SIZE=-1><EM>Edited by Labdog on 04/19/02 09:53 PM.</EM></FONT></P>
April 20, 2002 8:12:09 AM

Yes...and your point is? I've been to and read these links before - nothing new here - actually mostly old news...1994 news.

Keep in mind that the discussions of "digital HDTV" above are all discussing the trasmission signal - the signal that goes from the broadcast station to the receiver (whether that be over-air, cable or satellite). This is called, not HDTV, but DTV by the FCC. If the reciever is included in the HDTV set, yes this receiver does accept and process a digital signal - which it then converts to an analog HDTV signal before it is passed to the display circuit. All of the inputs on the back of current HDTV displays, with the exception of the over-air DTV input, accept only analog signals. My whole point is that the display portion itself is never digital, but analog. All digital HDTV may be in the future (with LCD/DLP/Plasma style displays (flat-panel or projection), but it doesn't exist in the consumer space today. Even if from production to reception is all digital, until the display itself is digital, HDTV is not all digital. I don't know of any consumer HDTV sets out there that connect via DVI (or similar standard) to the receiver - until they do, they are analog.

BTW, posting clips is cool, but posting a whole doc...the link usually is enough.

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.<P ID="edit"><FONT SIZE=-1><EM>Edited by ath0mps0 on 04/20/02 01:34 AM.</EM></FONT></P>
April 20, 2002 9:23:26 AM

i couldnt discuss w/ /help you anymore. bye.


if <b>you know</b> <font color=white>you don't know<i><font color=black>, the way could be more easy ...<font color=red>
April 20, 2002 9:28:35 AM

ROFL

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
April 20, 2002 9:38:44 AM

HDTV Television - An Introduction

EE 498
Professor Kelin J. Kuhn

...
<b>The Grand Alliance standard differs from all existing TV standards in three major ways. First, it is all digital standard -- to be broadcast with a packet transmission. Second, it supports multiple formats. Third, it is designed to be primarily compatible with computers rather than existing NTSC televisions.
...
The compression algorithms use both a motion compensated and discrete cosine transform (DCT) algorithm. The motion compensation exploits temporal redundancy. The DCT exploits spatial redundancy. MPEG-2 syntax will be used -- because it is already well established, will aid in world-wide acceptance, and will smooth the road to computer and multimedia compatibility. Audio will be supported by Dolby AC-3 digital audio compression. This will include full surround sound.
...
The Grand Alliance system is clearly designed with future computer and multimedia applications in mind. The use of MPEG-2 will permit HDTV to interact with computer multimedia applications directly. For example, HDTV could be recorded on a multimedia computer, and CD/ROM applications could be played on HDTV systems.</b>


i couldnt discuss w/ /help you anymore. bye. roflMAO


if <b>you know</b> <font color=white>you don't know<i><font color=black>, the way could be more easy ...<font color=red>
April 20, 2002 10:51:08 AM

Quote:
That signal is then decoded into *gasp*

another little few bit thing...

there is no loss to analogic convert a signal but some losses to digitize one.



if <b>you know</b> <font color=white>you don't know<i><font color=black>, the way could be more easy ...<font color=red>
April 20, 2002 6:24:08 PM

Oh, I completely agree that a single digital to analog conversion isn't going to yield significant signal degradation - In fact, it is necessary. The signal emanating from speakers (called sound) is an analog signal and the signal emanating from the screen (called sight) is also analog. The significant issue here is that HDTV is being called digital. Well, in the same sense I could call the NTSC signal I have been receiving from my satellite provider for the past 5 years "digital NTSC." As a matter of fact, cable and satellite providers do call it digital cable/satellite. The movies are converted from their native format (which could be digital) to digital and transmitted to the satellite, the satellite then transmits them to my dish which relays them to my receiver - the signal has been digital the entire time. Now the receiver decodes the MPEG-2 video and audio stream and converts it into analog for display on my "TV." Now along comes HDTV...what is different? Other than the display format and the bandwidth requirements, NOTHING!!! There are, however, FCC regulations that, in exchange for extra - free - over-air bandwidth, require the local stations to broadcast in the new display formats. These new display formats require the use of digital compression to accurately display the signal in the available bandwidth - hence we have DTV. The only difference (other than display format) here between current over-air NTSC and over-air HDTV is that the broadcast uses digital compression. HDTV signals from my satellite provider are still MPEG-2, still digitally compressed, just in a larger format. The receiver still converts the signal to analog, just like it did before.

My whole point here is to consumers buying HDTV - all of those video inputs on the back of your new HDTV set, with the exception of the DTV antenna jack, are ANALOG inputs. Even the antenna jack usually (legal requirement) accepts analog NTSC signals. If you buy an NTSC "ready" TV that has no internal DTV reciever, your new TV will not accept digital signals of any kind - they must be converted to analog first. VGA, Component Video, S-Video, Composite, etc. are <i>all</i> analog signals. I am not saying that they are inferior because of this, just saying that this is not "true" digital display.

I have gone multiple "rounds" with supposedly knowledgeable highend home-theatre "experts" about this issue in the past - they usually insist that all, or most, of the inputs on the back of their offered HDTV sets/projectors are digital while they are not. They are often surprised to find, after further research, that I am correct in this.

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
April 20, 2002 9:37:50 PM

Quote:
In fact, it is necessary. The signal emanating from speakers (called sound) is an analog signal and the signal emanating from the screen (called sight) is also analog.

lol -

we dont speak here about speaker or CRT but digital HDTV signal which is, that is right, encapsuled by an analogic support/transport signal over-air.

& by the fact there is a DAC, then ADC conversion for broadcast signals, there is no significant signal degradation.

& the broadcast source signal from channels is digital.

<i>note
if you dont know exactly whats a broadcast transmitter follow those links:
<A HREF="http://www.broadcast.harris.com/product_portfolio/produ..." target="_new">first link</A>
<A HREF="http://www.broadcast.harris.com/product_portfolio/produ..." target="_new">second link</A></i>


Quote:
My whole point here is to consumers buying HDTV - all of those video inputs on the back of your new HDTV set, with the exception of the DTV antenna jack, are ANALOG inputs. Even the antenna jack usually (legal requirement) accepts analog NTSC signals. If you buy an NTSC "ready" TV that has no internal DTV reciever, your new TV will not accept digital signals of any kind - they must be converted to analog first. VGA, Component Video, S-Video, Composite, etc. are all analog signals. I am not saying that they are inferior because of this, just saying that this is not "true" digital display.

yes, but what have you against analog CRT, they are, for the moment, better than LCD {digital} displays.


anyway TV has already a first step improvment with HDTV

- digital broadcast source
- High Definition enhancement
- less distortion, interference & parasite

maybe i forget several...


note
the HDTV goal is "everything digital for enhancement" but however this goal for the moment is not yet reached.


if <b>you know</b> <font color=white>you don't know<i><font color=black>, the way could be more easy ...<font color=red>
April 21, 2002 1:24:00 AM

Quote:
but what have you against analog CRT, they are, for the moment, better than LCD {digital} displays.

I have nothing against analog CRTs, nor do I have anything against high quality digital displays - my contention is that people (vendors and consumers) are calling their HDTV's "digital" when they are actually primarily analog.

Quote:
anyway TV has already a first step improvment with HDTV

- digital broadcast source
- High Definition enhancement
- less distortion, interference & parasite

One of my primary contentions is that digital broadcast source is something that has been available for years on cable and satellite systems - this is only new for OTA DTV. Most new TV shows are already being recorded in digital from the start - even for NTSC broadcast. Less distortion, interference etc. is the same - been there, done that - on cable or sat. Most people buying HDTV aren't interested in OTA signals - if I'm spending several thousands of dollars on an HDTV set, I already have cable or satellite and OTA external antennae are probably against the T's & C's in my community. OTA DTV is a novelty for most HDTV owners. It is only good for watching a few primetime network shows. Everything else comes from cable or sat.

The only real benefit of HDTV is the display format - which on current HDTV displays is analog.

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
April 21, 2002 8:13:48 AM

Quote:
Most people buying HDTV aren't interested in OTA signals - if I'm spending several thousands of dollars on an HDTV set, I already have cable or satellite and OTA external antennae are probably against the T's & C's in my community. OTA DTV is a novelty for most HDTV owners. It is only good for watching a few primetime network shows. Everything else comes from cable or sat.

sat is not an OTA transmission system ?           :smile:



if <b>you know</b> <font color=white>you don't know<i><font color=black>, the way could be more easy ...<font color=red>
April 22, 2002 10:42:43 AM

Good one... haha. Actually, the signal travels out of and back into our atmosphere, so no... :tongue: That's why it's called sat....

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
April 22, 2002 1:23:05 PM

yeah, hw.

you are playing with sat which is a non-terrestrial system & cable which is one.

& you mixed up both. rofl

[lol]<i>note: Over The Air is over & not under.</i>[/lol]


<i>if <b>you know</b> <font color=white>you don't know<font color=black>, the way could be more easy ...<font color=red>
April 22, 2002 1:28:31 PM

<i>i love this forum to demonstrate to each one, one by one, not who is the best but who is the worst. roflMAO     :smile: </i>


<i>if <b>you know</b> <font color=white>you don't know<font color=black>, the way could be more easy ...<font color=red>
April 22, 2002 1:36:00 PM

lol

Actually I didn't mix anything up - the FCC doesn't consider Sat to be OTA. And they treat cable and sat differently than OTA (and from each other as well).

Anyway, the point is that DTV is nothing new and HDTV "only" provides a newer, better, higher quality, ANALOG display format that can also be transmitted from traditional terrestrial based OTA stations in a "new" digital signal. Everything else (digital production, digital transmission, digital surround sound, etc.) is nothing new to NTSC formatted TV - they have been around for years.

I thought a thought, but the thought I thought wasn't the thought I thought I had thought.
April 22, 2002 1:46:47 PM

Quote:
Anyway, the point is that DTV is nothing new and HDTV "only" provides a newer, better, higher quality, ANALOG display format that can also be transmitted from traditional terrestrial based OTA stations in a "new" digital signal. Everything else (digital production, digital transmission, digital surround sound, etc.) is nothing new to NTSC formatted TV - they have been around for years

lol, its the reverse.


<i>if <b>you know</b> <font color=white>you don't know<font color=black>, the way could be more easy ...<font color=red>
April 22, 2002 1:51:41 PM

If you mean that the transmission is over an analog carrier, of course, but the embedded signal is digital which is then converted to an analog display signal by the receiver. Anything else?

If the thought I thought I thought had been the thought I thought, I wouldn't have thought so much.
April 22, 2002 2:00:40 PM

ARGHHH, you bother me.

stay in your positions & forget that i have tried to point out. lol


<i>if <b>you know</b> <font color=white>you don't know<font color=black>, the way could be more easy ...<font color=red>
April 22, 2002 2:47:27 PM

Well, too bad for us both... I was hoping that we could really have a constructive discussion. I am not unchangeable in my position, but you have to make a lucid argument - not just recycle old links.

If the thought I thought I thought had been the thought I thought, I wouldn't have thought so much.
April 22, 2002 5:09:52 PM

i dont want again to flame because of a polemic discussion.

my argu were precized comming from Federal Standard & others.

my links are old ones: some yes, others not.

in last FYI
1- i would like to point out that the current tech is based on the previous one.
2- when you put forward old NTSC tech, what the worst one ?
<i>my</i> "old" HDTV FFC links or <i>your</i> 50 years old NTSC format ?
(which has been created in 1954)


             :tongue:

<i>anyway we can retry to discuss on this topic... :) </i>


<i>if <b>you know</b> <font color=white>you don't know<font color=black>, the way could be more easy ...<font color=red><P ID="edit"><FONT SIZE=-1><EM>Edited by Labdog on 04/22/02 01:39 PM.</EM></FONT></P>
April 22, 2002 7:19:37 PM

Quote:
1- i would like to point out that the current tech is based on the previous one.

So we agree.
Quote:
2- when you put forward old NTSC tech, what the worst one ?
my "old" HDTV FFC links or your 50 years old NTSC format ?
(which has been created in 1954)

Well, I guess last dig I made wasn't really that constructive, was it? Don't get me wrong here - I'm not saying NTSC is as good as or even approaches HDTV for quality. I am all for HDTV and enjoy it.

Point 1) What I am against, however, is the mis-representation of how much of a leap it is. Yes it <i>is</i> a huge leap in quality. Yes, it is really, really, cool. Yes, it does let me display my computer screen on my "TV" with excellent quality (1080p) - something that couldn't be done with NTSC/PAL/SECAM. But, digital transmission is nothing new, really, especially for those in HDTV's current market. Digital production is also nothing new.

Point 2) Network television fought hard against having to upgrade the television standard, arguing for one that they didn't have enough bandwith. When the FCC granted them free bandwidth and a digital compression standard (DTV) to use they wanted to simply compress their old NTSC broadcasts and have more channels (more advertising revenue). The FCC said "no way!" and theatened to take the bandwidth away - eventually setting a conversion deadline. So, when stations start broadcasting using their new DTV stations and simply, for the most part, send NTSC signals and call the concoction "HDTV," I'm not impressed. The few programs that are actually broadcast in 720i+ are generally spectacular in quality.

Point 3) Television manus, vendors and stations are claiming that HDTV is digital (which some of it is or can be) and are using it as a buzzword. The only part about HDTV that is digital (that is not also available in digital for NTSC) is the standard over-the-air transmission medium (DTV). If you have digital cable or digital satellite (like most of the people in the market for HDTV), the only change for you will be picture quality - an excellent change that may stun you with its realism, but your cable or satellite digital receiver is already just as "advanced" as the DTV receiver in HDTV sets. The inputs on the back of consumer HDTV sets are analog inputs for analog signals (except for the DTV antenna jack). This is not bad. Just don't let your local home theatre rep. tell you that the progressive component-video signal going from your computer/receiver/DVD player, etc. is digital - it is not - just like the signal from your PC to your CRT monitor is not. The real difference here is the display format.

Point 4)(and my original one) The FCC differentiates between HDTV (as a display format) and DTV (as an OTA broadcast medium). TV stations and the TV manufacturers industry don't seem to make this same distinction - stations/networks lump everything that goes over their DTV stations or can be received via DTV (in HDTV format or not) as HDTV. Yes, the quality of NTSC broadcasts over OTA DTV do increase compared to OTA NTSC, but there is no difference in quality than with digital cable or satellite. Therefore, they should not be calling this HDTV. Yet, they do. IMHO, HDTV is only really HDTV when the signal is 720i/p or 1080i/p (preferrably progressive) regardless of whether it is broadcast via OTA, Cable, Satellite, etc. This narrows HDTV (in my thinking) to just the display format - everything else can be had without the format (and is therefore not HDTV).

Now, back on topic - If the signal from your device (Computer, DVD player, DTV/Cable/Satellite receiver) uses a VGA or Component-Video cable - it is potentially progressive. That signal is considered progressive (not interlaced) if the vertical refresh frequency is 60Hz or greater and the entire image is re-drawn every refresh cycle.

If the thought I thought I thought had been the thought I thought, I wouldn't have thought so much.
April 22, 2002 8:49:42 PM

yes, Have a Nice Day As Well. lol


<i>my name is rhetoric...</i>
<i>if <b>you know</b> <font color=white>you don't know<font color=black>, the way could be more easy ...<font color=red><P ID="edit"><FONT SIZE=-1><EM>Edited by Labdog on 04/22/02 04:59 PM.</EM></FONT></P>
!