What is High Definition Television

A Crash Course on High Definition Television

A television with high definition is a kind of broadcasting system which is digital and its resolution is higher compared to other traditional formats. Although there are early high definition television with analog formats broadcast over Japan and Europe, high definition television is using a digital broadcast because it needs less bandwidth. This kind of technology is introduced in the United States during the 90's by an electronics company group which is known as the Grand Alliance of Digital HDTV. By 2000, there are already a high amount of televisions, with a high definition standard, having a competition in the developing market. Recent standards of high definition televisions are described by a union of telecommunication as 1080 active interlace or 1080 with scan lines that are progressive or as 720 scan lines which are progressive and uses an aspect ratio of 16:9. This kind of technology also offers an audio which has a quality like that of a theater since it is using a format known as Dolby Digital which supports a surround sound of 5.1. The name “high definition” refers to the specifications of the resolution. During this year, 2007, a number of 24 million households in the United States have high definition televisions. But sadly, only a half of this number is actually receiving high definition programming because some of them do not know that they have to obtain special receivers to have HDTV on their cable, or they need to utilize tuners for their HDTV for them to have broadcasts over the air.

A law has been passed stating that new sets of television that have broadcast signals over the air must have HDTV or digital tuners for programs which are broadcast digitally, this also includes portable television which are pocket sized. As an order of the commission on federal communications, all the broadcasts in the United States should all be digital by 2009. This order is made to help give an easy transition to the newly established standards.

High definition television does not make the quality of conventional channels better; a different tuner is needed to get varied signals from new sources with an added cost. These are usually over the air with the use of an antenna. Many cities in the United States broadcast HDTV over the air because of main network affiliates. But only a few people watch this technology through this way. Tuners are also capable of being fitted to computers in order for it to receive signals. For some televisions, they already have a high definition tuners established in them. Tuners are not required for cable which broadcasts digitally. There are companies of cable television that provide high definition television broadcasts as a section of their digital service. This technology does not operate with analog service. To get a clear signal, an HDMI cable should be connected to your monitor instead of component or composite cables. Some carriers of cable services offer playback on HDTV which is usually demanded by viewers. This has two options, free or charged viewing of common programs or movies. Some systems of video games can output a high definition resolution. Standards of optical discs can also offer signals of HDTV.

Television with high definition resolution has better quality of images compared to standard television. The great picture clarity implies that the images shown on the screen are less fuzzy. The other advantages of high definition television is a motion that is smoother, the colors are richer and appear more natural, a theater-like surround sound and a possibility to use your high standard equipment with your high definition television.  The digital signals deliver excellent images. Usual imperfections of conventional television are a thing of the past. Double images and weak signals do not happen when your television set has a high definition resolution. The pictures' colors appear realistic as a result to great bandwidth. Gaps in the middle of scanning lines are now invisible or even smaller.

The “i” on 1080i means interlaced while the “p” in 1080p means progressive. With an interlaced scanning, the lines are divided into halves; the first half is colored on a frame while the second half is colored on the other frame. In this way, the bandwidth is reduced and the rate of the frame is raised to fifty up to sixty per second. On the other hand, a progressive scanning shows all the lines together at sixty frames/second. This kind of scanning utilizes more bandwidth. The surround sound is aired together with conventional video signals of HDTV, enabling a theater-like sound capability.

This technology also uses a notation for the formats; the amount of lines shows their resolution vertically. The specific format of pixels, enables an encoding of sixty frames per second, these format are 720p60. A format, 1080i50 enables an interlaced encoding of 25 frames/second.