Much confusion exists about the difference between HD (High Definition) and Digital TV, and many people know only that HD TV is more expensive and provides a better picture and better sound. Part of the confusion lies in the fact that although a High Definition TV signal must be digital, it is not necessary for Digital TV broadcasting to be High Definition.
Digital TV refers to digitally transmitted off-air signals, usually in ATSC, instead of the old-style analog signals, NTSC. Digital television broadcasts can consist of both High-definition and Standard-definition programs. High Definition pertains to the video resolution, which may be 720p, 1080i or 1080p. The small “p” signifies “progressive,” and the small “i” signifies “interlaced,” the two types of scanning techniques for television sets. A 720p resolution does not have as many pixels, so the picture will not be perfect, but it reduces the blurriness that would otherwise appear during sporting events and other action programs. A 1080i resolution has more lines and more pixels but does not prevent the blurry feature. Therefore, a 720p image is not much sharper, but it is less blurry, and a 1080i has a sharper picture, but the image may be blurry. A 1080p combines both the 720p and the 1080i to produce the best picture.
Any television set can receive a digital signal converted to analog. Any satellite TV box, cable box or pay-TV service box will work with a TV that accepts a coaxial connection. However, to receive an HD signal, a consumer must have an HD TV.
The definition of a TV depends on the number of lines the television displays to produce a picture. The Standard Definition resolution in most of the older TVs is about 480 lines.
Resolution is the primary difference between HD and Digital TV, and digital resolution is either Standard Definition or High Definition. Even the older big-screen televisions that operate in SD show only 480 lines of resolution. Most of today’s newer televisions are High Definition with at least 720 lines of resolution. The highest resolution is currently 1080p, but that number keeps increasing.
The quality of an HD signal is obviously better than is the signal received in SD. Depending on the television and the service provider, both the visual and audio quality of High Definition is generally much better than are those qualities in Standard Definition.
Unlike Standard-definition TVs that are ready to view, there are additional requirements for obtaining the benefits that HD TV has to offer.
Consumers must have HD TV-compatible televisions or TVs with their own HD tuners to view HD programming. Consequently, there is no reason to have HD service without an accompanying HD TV. However, an HD television set will work with SD signals, but the picture will not be as nice. In fact, an SD signal on an HD-compatible television with a screen larger than 32 inches will often look inferior. The picture will look progressively worse according to the size of the HD screen, with the largest screens showing the poorest images.
The cost of HD is significantly higher than the cost of SD digital. Viewing a Standard-definition digital signal does not require any special television set, but a High-definition television set is necessary to watch HD.
Consumers can use component cables, but to get the full potential from HD TV, viewers should connect their HD TV with HDMI cables or other HD cables.
Watching television in high definition requires using an HD tuner, known in the pay-TV industry as a box or receiver, and each HD TV must have a separate receiver. The tuner may be subject to upgrade fees or extra lease fees.
Viewers need HD-programming service providers to supply the HD signals for them. The major pay-TV services offer High Definition programming, and some networks offer free programming in High Definition, but others may charge about $10 extra for the service each month.
Viewers who enjoy watching and listening to high-quality television programming should appreciate HD TV for several reasons.
· High-definition signals improve both the sounds and pictures of television programs to produce more detailed and crisper programming.
· HD normally offers surround sound instead of the stereo sound provided with digital service.
· An HD TV and HD receiver along with HD programming present an image five times clearer than that shown on a standard television because of the HD TV’s higher resolution capacity and the larger number of pixels in the signal received.
· HD television screens are wider than are common analog screens.
· Viewers of HD TV can watch movies as shown in theaters with no reformatting necessary.