HDTV

HDTV is the acronym for High-Definition Television. It is a type of digital television. Its remarkable advantage over other traditional systems of television like NTSC (National Television System Committee), SECAM, PAL (Phase Alternating Line) etc is greater resolution. It uses a digital broadcast system and needs lesser bandwidth for broadcasting. The HDTV refers not only to image resolution but also to the photographic or video graphic Medias which give similar resolution.  The images in HDTV are bigger, brighter, flatter, and sharper. The standards for the HDTV broadcast are given in Digital Video Broadcasting (DVB) and also in Advanced Television Systems Committee (ATSC) standards.

Another main feature of the HDTV is that it uses Dolby Digital format for the surround sound system and so provides a cinema-quality audio. It also contributes for the large screens and projectors. An HDTV requires a high definition signal also called HD signal which of course does not aid in the performance of SDTV channels.  The HDTV programming can be got through the antenna, cable and satellite.  It is also possible through IPTV which is delivered through broad band connection.

There are a number of types of HDTV displays:
1) Direct-view: In this type the image is painted on a screen coated with phosphorus using cathode ray technology and an electronic gun which is capable of scanning too.
2) Plasma: In this type, picture is created from the gas which contains atoms of xenon and neon and also a large number of electrically charged electrons and atoms. When the power is on the atoms and electrons releases a huge amount of energy on collision and as a result the xenon and neon emits photons. Compared to direct view TV, plasma TV provides a large viewing area with less thickness and also contribute for outstanding quality of pictures but is costly.
3) Rear screen: This type has got a projection screen similar to that of CRT in a direct view type for displaying images. Rear Screen TV offers bright colors and also high resolution images.
4) Front screen projection: The working of this type is similar to that of Rear screen TV. The cathode ray tube forms a separate unit from which the image is projected to a screen in the front of the TV. The size of the view is restricted to the size of the room. The main draw back of the front screen projection TV is that it will work only in dark rooms.

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