All About HD TV

1. Introduction

Part of the phenomenon of filmed entertainment of any kind can be attributed to the way the human brain processes visual information. Two processes most of us do naturally affect the way we perceive photographic, electronic or digital images and motion.

Most of us would accept this information as common knowledge, but here's a quick review.

2. How do we see images?

If we zoom in close enough on the images we see in print or on any screen, we realize that what our brain receives as that image is the result of its ability to assemble a collection of small dots called pixels into some kind of meaningful order.

3. How do we see motion?

If images are shown in rapid succession, our brain is able to assemble them into a fluid, single moving scene. Motion picture technology discovered that if these images were photographed and projected at 24 images or frames per second, the most satisfying lifelike motion was created.

Video technology modified the number to approximately 30 frames or image fields per second because the way video is played back works on a slightly different principle than that of the classic film projector.

4. The Tube

Today's television, often called "THE TUBE", works because of piece of equipment called the Cathode Ray Tube or CRT.
The image signals are converted into electrons which are emitted from a cathode. These electrons are attracted and accelerated by positively-charged plates, forming a focused ray. Magnetic coils direct the ray through the vacuum tube where it eventually hits a phosphor coating on the back of the screen. The electrons hitting the phosphor coating cause the phosphor to radiate and produce an image.

For a standard NTSC broadcast, an entire image is created when 525 lines are drawn in succession by this ray of electrons. The process is repeated 30 times a second to form what we recognize as a television picture.

The basic phenomenon of television is the result of connections made between human perceptions and complex electronic image delivery system.

The Federal Communications Commission has set 2006 as the transition year for all television broadcasts to be switched from analog to digital. While this does not mean all broadcasts will be in high definition by 2007, the infrastructure will be in place. Because of the highly competitive nature of the television industry, more HDTV can be expected. Cutoff date of Feb 19,2009 has been formally announced.

When broadcasters start transmitting HDTV signals, what will happen to current analog television?
HDTV in the U.S.A.

Compared to the January - February sales period of 2003, 2004 sales of digital television products increased by 124% and represented more than 1.3 billion dollars in sales.

The Federal Communication Committee has set 2006 as a transition year for consumers, manufacturers and cable and satellite providers to switch from analog to digital television. Their mandate includes the plan to completely phase out of analog (standard definition signals) by 2009.

Multicasting is what broadcasters are doing now, which means they are offering the same program in various formats (analog, digital, HDTV).

Who is broadcasting HDTV to USA?

Currently, the following HD channels are available:

CBC (special event programming)
CTV
CITY TV
TSN HD
Sportsnet HD
ABC
CBS
NBC
FOX
PBS
Discovery HD
Movie Central
The Movie Network
Viewers Choice
Various Pay-Per-View Channels

Before purchasing any equipment, it would be wise to make sure that HDTV is available in your area. Many cable companies and satellite providers offer HDTV service, but it is not available in all locations. Depending on the kind of set you buy and how you receive the HD signal, you may also have to purchase or rent a digital tuner/receiver.
There are two important steps in order to view HDTV. The first is to acquire an 'HD-ready' or an 'HD-compatible' television set. It's likely any new set fitting either of these descriptions will be a widescreen television, but there are some 4:3 picture aspect-ratio HD sets available.

'HD-compatible' sets are able to display a high-definition picture, but they require an external digital receiver or tuner. If you expect to rent an external digital receiver from your cable or satellite company, this is likely the kind of set you'll buy. HD-compatible sets are certainly cheaper than their HD-ready counterparts.

'HD-ready' sets don't come with a built-in digital tuner/receiver and need a set-top box (STB) to display DTV or HDTV services. HD-ready sets usually price at least a few hundred dollars more than their HD-compatible competitors.

The second step is to subscribe to HDTV broadcasts through your local cable or satellite provider. In addition to signing up for HDTV service, you will need an HDTV receiver (from your provider).

If you wish to take advantage of the increased sound quality, you would also need a home theatre system.
What is a 'plasma' television? What is an 'LCD' television? Is one better?

Most plasma displays are 42 inches or more and all of them have a 16:9 aspect ratio. Distinctly different from solids, liquids, and normal gasses, plasma is an electrically neutral highly ionized gas. Two thin sheets of glass are used to enclose a plasma solution that, when electrically charged produce images. Typically, plasma screens are only a few inches thick and can be free-standing or mounted on walls.

Images on LCD (liquid crystal display) screens are the result of liquid crystals being activated by electronic fields. More like computer monitors than standard televisions or plasma displays, LCD sets have visible sets of pixels and the sets are usually not bigger than 32 inches. LCD screens tend to be more expensive than televisions of the same size, but like plasma screens are only a few inches thick.

As to the question of which is better, the most reliable guide is your own eye. But a word of caution: there are some plasma or LCD sets on the market that are NOT able to display high-definition images. Almost all are presented to consumers as HDTVs. Be sure you're getting what you're looking for when shopping around.

How do I get the most out of my new HDTV?

If you now have an HDTV and have subscribed to HD service, there are a couple of ways to maximize the picture and sound quality of your system.

Connect your HDTV receiver to your HD television using a component video cable. This cable splits the television signal into a luminance (brightness) and two chrominance (colour) channels. By doing this, the television's internal decoders are bypassed, resulting in a truer representation of the original picture.

A home theatre system is recommended to take full advantage of the digital surround sound from HDTV broadcasts. Use either a digital coaxial cable or an optical (Toslink) cable to connect the sound from your HDTV receiver to your home theatre's A/V receiver.