HDTV Explained

HDTV Explained
What is HDTV?
HDTV stands for High Definition Television. It is a digital format that provides an extremely high-resolution picture, accompanied by amazing digitally enhanced sound, all presented in glorious widescreen. What can be confusing is that HDTV is used to refer to several things: a type of TV, a digital broadcast method, and a special way to produce TV shows and movies. Viewing nirvana is achieved when all three parts of HDTV converge; a show or movie that is produced using High Definition technology, is transmitted via a HDTV television signal (from a HDTV channel), and enjoyed on a HDTV television (preferably a big widescreen set) with a surround sound home theatre audio set up. Still, even watching regular TV or a DVD on a HDTV is visually stunning. And that is why more and more people are getting on the HD bandwagon.

Digital transmission uses less bandwidth to transmit more information than analogue transmission. Digital TV is totally free of interference such as snow and "ghosting". Standard Televisions have a resolution of 625i, HDTV has a higher resolution of either 720p, 1080i and in some cases 1080p, and 5.1-channel Surround Sound. And since it is digital, the signal doesn't lose strength and isn't susceptible to static and signal "noise".

A bit about the way that picture quality or resolution is measured. The numbers - 625, 720, and 1080, refer to the number of scan lines, or picture information lines, that make up the television image from top to bottom. The "p" and "i" stand for "progressive" and "interlaced" and indicate how the picture information is scanned onto the screen. With progressive format, the full picture updates every sixtieth of a second. In interlaced format, half of the picture updates every sixtieth of a second. Analogue television uses the interlaced scan format.

Why HDTV?
So what makes HDTV that much better? Let's look at the numbers:

* HD has 2.1 million or more pixels. That is a lot more picture information and that is what makes HDTV so crisp and detailed.
* HD has an aspect ratio of 16:9 versus the 4:3 aspect ratio of analogue. You get one-third more image area and it's that much easier to watch movies in their original format. The 16:9 aspect ratio actually more closely matches the viewing angle of the human eye, making for a more immersive entertainment experience.
* HD images are made up of from 720 to 1080 horizontal scan lines. Again, a lot more detail is possible with that much more visual information on the screen.
* HDTV can provide 5.1 channel Dolby Digital sound, equal to what you hear in a cinema. Plug in a home theatre audio system and you can hear the distinctions between sound effects, dialogue and music. Analogue can't offer anything close to that!


With so much more visual information (more pixels and more scan lines), HDTV provides amazing detail. In fact, many people are startled by the amount of detail they see. And the multi-channel sound and widescreen format make the experience even more rewarding. In order to enjoy all the future high definition programmes, you must have a HD Ready TV. Many programme makers – including the BBC – are already filming in High Definition. And HD will be available through Sky from 2006. You will be able to enjoy a host of your favourite programmes in unbelievable quality. All HD Ready screens will also work excellently with standard broadcasts until the HD broadcasts arrive. Purchasing an HD Ready TV is a way of ‘future proofing’ yourself and enhancing the picture quality and enjoyment you get from the TV.


What is HD ready?
A HD ready TV must have HDMI or DVI connectivity in order to accept a digital signal from the HD receiving equipment. It must also have a resolution of either 720 or 1080 lines.


What Is HD Compatible?
The term "HDTV compatible" is a term used by the major manufacturers to designate a TV which is capable of displaying a high definition signal. However, the set does not contain a HDTV tuner. The electronics are all in place so that it will be able to display high definition. However, in order to actually view any high definition programming, the customer must add a separate box, which is most often referred to as a "high definition receiver" or a "high definition tuner" or a "high definition set top box".