Buyers' Guide

How Does HDTV Work? TV/Audio/Video Buyers' Guide

In the world of HD, there are two basic choices in televisions: TVs that include a digital tuner (HDTVs), and TVs that use a separate digital tuner (HD Monitors). Current regulations require all televisions 25" and larger to include a digital tuner, so HD monitors are normally found only in products under this size. HD monitors and HD televisions offer the highest form of DTV performance—about 5x more picture detail than analog. This resolution is used by most broadcasters, and the image quality is nothing less than stunning. An important development in DTV has been the introduction of Digital Cable–ready televisions. These are televisions that include special circuits that eliminate the need for a separate cable set-top box. Digital Cable–ready televisions can be identified by a slot, in the back of the set, meant to accept a CableCARD®. When the CableCARD is received from your cable operator and inserted into the slot (easily done by any consumer), it allows you to view both scrambled– and subscription–digital programming. It’s worth noting here that some cable operators will assert that you must utilize one of their set-top boxes to access digital cable—a method which costs more per month, and is harder to use. By law, however, cable operators must give you a CableCARD if you so request.

Important Things to Know:

• Not all DTVs include a CableCARD slot. This is an important capability that makes your TV easier to set up and use, and does not require the use of a separate cable set-top-box.
• Not all CableCARD televisions include a program guide. It's important to have a program guide so you can easily navigate all the cable and broadcast channels. All CableCARD-compatible LG DTV's include a program guide.

Broadcast Signals

There are three ways to get an HDTV broadcast signal:
Broadcast: There are currently 1,315 stations in the U.S. transmitting digital TV signals. Many of these stations broadcast high-definition content as well. HDTV is offered by CBS, NBC, FOX, WB, UPN, and PBS stations. All over-the-air content is free. (Requires a digital tuner—either built into the TV, or as a separate set-top box.)
Cable: Many cable systems offer premium HD movie channels and regional sports, as well as some local HD broadcast channels. Cable also has its own exclusive network called In HD and In HD 2, providing movies, music and varied programming in HD quality. (Requires a CableCARD® and digital cable–ready TV, or a digital HD set-top box.)
Satellite: The satellite companies are continually expanding their HD offerings. Currently, these include movies on HBO, Cinemax, Showtime, The Movie Channel, Starz, HD Net Movies, and Encore. In addition Arts, Music, Animation, Extreme Sports, and Travel Log programming are now available in HD, round the clock, via satellite. (Requires special satellite HD receiver. Availability of local HD broadcast channels varies by market and satellite provider.)

What is the difference between analog and digital Broadcasts?

A digital direct-view TV will have a much greater resolution than its analog counterpart. Almost all digital TVs can display progressive-scan DVDs (480p) and HDTV (usually 1080i) at full resolution, where as analog cannot. With a digital TV you are offered better quality picture and sound, giving you the best entertainment experience in your own home.

Broadcasting

With analog broadcasting signals, the quality of the reception is directly related to the quality of the signal. But, with digital broadcasting signals, no matter how strong or weak the signal, the quality remains the same on your TV—unless there is no signal at all.

Image Rendering

TV displays old and new are made up of a series of horizontal lines, which in turn are comprised of tiny dots, called pixels. The number of these lines and dots make up what is called "resolution."

Image Quality

Sound

Resolution

Under the ATSC system, networks can broadcast in any resolution they desire. But, to ensure that consumer televisions receive their signals, networks have standardized their broadcasts and consumer television production has followed suit, resulting in three categories or formats of broadcast resolution (amount of picture detail): Standard Definition (SD), with the same resolution as today's analog signals (but again, with digital displays, interference is eliminated and the picture is perfect); Enhanced Definition (ED), with the same resolution as today's DVD players; and High Definition (HD), which has about 6x the resolution of standard.
These differences are also reflected by signal shape, with SD signals "standard" shaped (with a 4:3 aspect ratio), and ED and HD signals "widescreen" (with a 16:9 aspect ratio). HD is further differentiated in this regard, broadcast in two signal formats: 720p x 1280 and 1080i x 1920—the first interlaced (TK definition), and the second, progressive (TK definition), though it’s nearly impossible to discern any difference between the two.