Technology of television
Television technology is an umbrella term for telecommunications, sound and video technology, is related to the television. Partial is meant by the television industry even the technology of a television set.
Picture and sound are recorded by television cameras and then processed by image technology, ie technically worked, and cut. The sound and communication equipment does not really belong to the television technology, but uses their technologies.
When production is decided which quality is guaranteed. These features begin with the picture quality (eg black and white or color and resolution ) and end with the sound quality. If only differences in brightness during recording and playback of images into account, then one speaks of black and white television. In contrast, is spoken by the color television, although color information is recorded and reproduced, transmissions of color television can also be received on black and white televisions. The color TV is now in the industrialized world standard.
If both images and sounds on a storage medium, such as a so-called magnetic recording ( VTR ), recorded, they may also at a later date, are sent if necessary after processing, via a transmission path. The immediate transmission of the recorded data is called a live broadcast.
The transfer takes place initially from the transmitter station ( studio ) or outdoor shooting ( then via ue - car and satellite) to the distribution centers of the cable operators. Subsequently, the signal to the television towers and the transmission stations for satellite is forwarded. There are different signals that are transmitted or received, depending on the country in various television standards. In Germany this is the standard PAL 50 analog or DVB -S (satellite digital) or DVB- T (terrestrial digital) with MPEG2 compression. New HDTV OB truck for high resolution images in 1080i standard use DVB -S with MPEG4/AVC-Kodierung.
For television, usually modulated RF transmission via antenna or earthbound in coaxial or fiber optic cables (cable TV) is used. To receive an additional digital decoder is ( a so -called set -top box ) or a suitable terminal device ( in which the decoder is the same as today's conventional analog receiver section already integrated) or a digital TV that no longer needs a decoder, necessary ( IDTV ).
In the area of the antenna and cable television today is the analog transmission of the information partly still in use ( analog TV ), although the recording and editing of images and sounds for several years in the digital domain. The switch to digital transmission of data (digital television ) was the terrestrial television in Germany the end of 2008, in Austria mid-2011. During Satellite TV DVB -S conversion to digital television in Germany was completed on 30 April 2012. When Cable TV DVB -C is the conversion in full swing. Cable Germany, however, has announced that it will still operate the analogue broadcasting for several years in parallel with the digital.
Image and sound
The transmission to the terminal is done either by cable, by satellite ( non- terrestrial) - satellite TV, an Internet connection, via an antenna or via terrestrial frequencies - Antenna TV.
Mechanical television was realized historically in both the recording and when playing with the Nipkow disk; electronic television for the first time with the Ikonoskop tube in the recording and the cathode -ray tube during playback. As Ikonoskopröhre developed later than the cathode ray tube, there was a short time, a mixed form.
The analog transmission type most commonly used is the amplitude modulated television, short AMTV, when satellite television, there are only analog FM TV.
The distinction in mechanical television and electronic television, which was created during the first television experiments, is now insignificant: mechanical recording and playback devices have been used commercially only in the initial phase until 1935.
In addition to the television screen in some cases additional signals are transmitted to end-users, but can not always be processed without additional equipment:
- Tones (almost always)
- Teletext - written information of a TV channel ( ARD / ZDF 1980-2000: Teletext called ), very common today - but with a using a 20 -year-old system
- Video Program System (VPS ) or Showview pulses that a recording device the actual beginning of a program they broadcast (Timer Programming) - relevant for VCRs
- Separate sound track - for bilingual with the transmission of an alternative language other than the language of communication in the country option
- Subtitles for the deaf or for language mediation ( foreign language The transmitted O-Ton)
The so-called analogue switch-off requires a switch on the TV. The vast majority of existing televisions and VCRs can not deal directly with the digital signals, so they need an additional device (set -top box, STB ), which receives the data, decodes and converts it into an understandable for the older electronics analog signal. Meanwhile, however, also appear with fixed TV ( IDTV ) or optional receiver technology (tuner) for DVB -C ,-S, and-T options on the market. Such devices perform, for example, Artec, Humax, Loewe, Metz, Sharp, TechniSat, Thomson, X4 -Tech. For the mobile DVB- H reception there on principle only fully integrated new equipment, often mobile phone combinations.
ZDF, in 2007, a new library called broadcasting concept that triggered criticism from private TV broadcasters. This called for a limitation of publicly - funded legal online products.