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Cable Television Network
Cable television or cable television network, formerly known as Community Antenna Television or CATV is a system of providing television, FM radio programming and other services to consumers via radio frequency signals , which originated in Pennsylvania in the late 1940's. Cable television spread quickly throughout the country to remote and rural areas with the help of Milton Shapp's innovative idea, a master antenna (MATV) that could be used for all televisions in a building.
Technology of Cable Television
Technically, cable television involves distributing a number of television channels collected at a central location to subscribers within a community by means of a branched network of optical fibers and/or coaxial cables and broadband amplifiers. Since the early 1990s, the most common architecture is the Hybrid fibre-coaxial network.
Coaxial cables are capable of bi-directional carriage of signals as well as the transmission of large amounts of data. Cable television signals use only a portion of the bandwidth available over coaxial lines.
Digital Television Review
Digital Television is considered as the most significant television innovation since color TV. Digital television technology begins a new era of convergence between home electronics and computing technology that will blur the line between work and play. Digital television combines three different ideas of signal, format and aspect ratio. Each broadcaster has an analog TV channel and a digital TV channel. One digital television channel can carry multiple sub-channels if the broadcaster chooses to do so. The reason that broadcasters can create sub-channels is because digital TV standards allow several different formats.
Formats of Digital Television Broadcasters can choose between three formats:
- 480i - The picture is 704x480 pixels, sent at 60 interlaced frames per second (that is 30 complete frames per second).
- 480p - The picture is 704x480 pixels, sent at 60 complete frames per second.
- 720p - The picture is 1280x720 pixels, sent at 60 complete frames per second.
- 1080i - The picture is 1920x1080 pixels, sent at 60 interlaced frames per second
- 1080p - The picture is 1920x1080 pixels, sent at 60 complete frames per second.
"p" stands for "progressive" and "i" stands for "interlaced". In a progressive format, the full picture updates every sixtieth of a second. In an interlaced format, half of the picture updates every sixtieth of a second.) The 480p and 480i formats are called the SD (standard definition) formats, and is roughly equivalent to a normal analog TV picture. The 720p, 1080i and 1080p formats are called the HD (high definition) formats. An analog TV has a 4:3 aspect ratio, that is, the screen is 4 units wide and 3 units high. For example, a "25-inch diagonal" analog TV is 15 inches high and 20 inches wide. The HD format for digital TV has a 16:9 aspect ratio, which is almost twice that of an analog TV.
HDTV Television Review(High Definition Television)
HDTV is the broadcast format of the future and of the present, too. By review of HDTV Television means broadcast of television signals with a higher resolution than traditional formats which will be in 16:9 formatting. Wide screen movies spurred the creation of HDTV. In wide screen movies, it was noted that people seated in the first few rows enjoyed a level of participation in the action that was not possible in the usual movies. So the screen had to occupy a great field of view to increase the sense of participation. Possibilities for special effects in movies increased. For many years, engineers have been working across the world to develop High Definition TV. HDTV means a wide screen TV with movie theatre quality, CD quality stereo sound and language options.
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