What is HDTV?Written by Gary Davis
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The aspect ration of normal TV is 4 x 3 (4/3 times wider than high). An HDTV screen has an aspect ration of 16 x 9, which is also known as wide screen. Higher sound quality using Dolby Surround. The Future of HDTV The FCC (Federal Communications Committee) has mandated that all TV stations in USA have to be able to broadcast HDTV programs by year 2006. The mandates of FCC do not have an impact on just broadcast companies, but also on cable companies and consumers. - Broadcast companies have to invest on new equipment like cameras, editing equipment, etc.
- Cable companies have to convert all of their equipment, including receivers at homes of their clients.
- Consumers may have to buy new equipment, like a top-box to convert digital signals back to analog signals, or even buy a whole new TV set.
HDTV is future, and a really big step forward. We once started with simple black and white TV, then moved to color TV, and wide screen TV. But all those systems were still based on same signals as original black and white TV used. When color TV was introduced it was not possible to force complete population to throw away their black and white TV-sets and buy a color TV set. Therefore a color TV signal still needed to be understandable for a black and white TV. This prohibited improvement of picture quality until age of Digital TV. The need to satisfy older TV sets no longer exists and much higher quality HDTV is available via Satellite TV Systems.
Gary Davis is owner of Dish Network Satellite TV, has several years experience in the Satellite TV Industry and has written several articles on satellite TV.
| | Analog vs Digital Transmission Written by Gary Davis
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Well..... Actually they do lose quality just like analog transmission system does. Surprised? No Problem. Most people don’t know that digital signals still need to be transmitted by analog transmission systems. The trick is that a digital system doesn’t record analog signals, but encodes analog signals into bits (zeros and ones). A sample is taken many times per second and size of each sample is written down in bits. For instance a sample with value of 9 would be 1001 and 11 would be 1011. The digital transmission system needs to transmit those zeros and ones, and it does this by modulating carrier wave. Low power for a 0 and high power for a 1 (This is most simple way of modulating. There are much more sophisticated forms of modulation, but it would take a whole book to describe them all.) So on receiving end, it doesn’t matter anymore what quality of signal is, as long as it still is possible to identify zeros and ones. Noise in received signal is no problem. A “1” with noise is still a “1” and a “0” with noise is still a “0”. Of course noise can not be too high, otherwise mistakes would be made and a zero would be received as one or a one would be received as a zero. So Digital Transmission Systems are better because they eliminate effect of noise completely. You don’t look and listen to a received signal from an original recording, but you look and listen to a reproduced signal of recording. The reproduction comes from an exact copy of original recording. The quality of what you see and hear now depends on your TV and Sound System. A high quality TV and Sounds System will give you high quality Video and Audio. The negative effects of (still analog) transmission have been eliminated from process. Satellite TV makes use of Digital Transmission Systems. What you see at home will always be of Digital no (much less) noise Quality.
Gary Davis is owner of Dish Network Satellite TV, has several years experience in the Satellite TV Industry and has written several articles on satellite TV.
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