Television technology
Television technology is an umbrella term for communications technology , sound technology and video technology that is related to television . In some cases, television technology is only understood to mean the technology of a television set .
production
Image and sound are recorded with television cameras and then processed by image technology , i. H. technically processed, compiled and cut. Sound and communications technology does not actually belong to television technology, but uses its technologies.
During production, it is decided which quality is guaranteed. These characteristics start with picture quality (e.g. black and white or color and resolution ) and end with sound quality. If only differences in brightness are taken into account when recording and reproducing the images, one speaks of black-and-white television . In contrast to this, color television is spoken of when color information is also recorded and reproduced, with color television broadcasts also being receivable on black-and-white televisions. Color television is standard in industrialized nations today .
If the images and sounds are recorded on a storage medium , such as a so-called magnetic recording (VTR), they can also be sent via a transmission path at a later point in time, possibly after processing. The instant sending of the recorded data is called live transmission .
transmission
The transmission takes place initially from the broadcasting center (studios) or from external shoots (then via OB vans and satellite) to the distribution centers of the cable operators. The signal is then forwarded to the television towers and the satellite broadcasting stations . There are different signals that are broadcast or received in different television standards depending on the country . 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 vans for high-resolution images in 1080i standard use DVB-S with MPEG4 / AVC coding.
For television, modulated high-frequency transmission via antennas or grounded in coaxial or fiber optic cables ( cable television ) is usually used. For reception, an additional digital decoder (a so-called set-top box ) or a suitable terminal device (in which the decoder is already integrated, just like today's analogue receiver) or a digital television that no longer needs a decoder, is required ( IDTV ).
In the field of aerial and cable television, the analog transmission of information is still partially in operation today ( analog television ), although the recording and processing of images and sounds has been digital for several years. The conversion to digital transmission of data ( digital television ) was completed in terrestrial television in Germany at the end of 2008, in Austria in mid-2011. In the case of satellite television DVB-S , the conversion to digital television in Germany was completed on April 30, 2012. The changeover is in full swing for cable television DVB-C . However, Kabel Deutschland has announced that it will continue to operate analogue distribution in parallel with digital for several years.
reception
Picture and sound
The transmission to the end device takes place either by cable , by satellite (non-terrestrial) - satellite television , via an Internet connection , via an antenna or via terrestrial frequencies - antenna television .
history
Mechanical television has historically been realized with both recording and playback with the Nipkow disc ; Electronic television for the first time with the Ikonoskop tube for recording and the cathode ray tube for playback. Since the iconoscope tube was not developed until later than the cathode ray tube, there was also a mixed form for a short time.
The most common type of analog transmission is amplitude-modulated television, or AMTV for short , while satellite television only offers analogue FM TV.
The distinction between mechanical television and electronic television that emerged during the first television attempts is insignificant today: mechanical recording and playback devices were only used commercially in the initial phase up to 1935.
Other signals
In addition to the television picture , additional signals are sometimes also transmitted for end customers, but these cannot always be processed without an additional device:
- Tones (almost always)
- Teletext - written information of a television channel (ARD / ZDF 1980-2000: Teletext called), very common today - but old with a use of a system 20 years
- Video Program System (VPS) or ShowView - impulses that transmit the actual start of a program to a recording device (timer programming) - relevant for video recorders
- separate audio track - for two-channel sound with the option of transmitting an alternative language other than the lingua franca of the country
- Subtitles for the deaf or for language mediation (foreign-language interview)
IDTV
The so-called analog switch - off requires a change in the television set. The vast majority of existing televisions and video recorders cannot handle the digital signals directly, so they need an additional device ( set-top box , STB ) that receives the data, decodes it and converts it into an analog signal that older electronics can understand. In the meantime, televisions with built-in ( IDTV ) or optional reception technology ( tuner ) for DVB-C, -S and -T are also appearing on the market. Such devices lead z. B. Artec, Humax , Loewe , Metz , Sharp , TechniSat , Thomson , X4-Tech. For mobile DVB-H reception, there are basically only fully integrated new devices, often mobile phone combinations.
The ZDF , in 2007, a new library called broadcasting concept, which sparked criticism from private TV broadcasters. These demanded a limitation of publicly financed online products.
literature
- Dieter Stotz: Computer-aided audio and video technology . 2nd Edition. Springer Verlag 2011, ISBN 978-3-642-23252-7
Individual evidence
- ↑ computerbild.de: DVB-T: Changeover to digital television in Germany completed , December 11, 2008, accessed on December 20, 2011
- ↑ satundkabel.de: Austria has completed the complete conversion to DVB-T ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. , June 7, 2011, accessed December 20, 2011
- ↑ Uwe Mantel: Kabel Deutschland: Analog TV will remain for years , July 29, 2009, accessed on December 20, 2011
- ↑ Example of a digital television from Humax
- ↑ 2. Example of a digital television from Humax
- ↑ Example: Loewe Digital + ( Memento of the original dated September 27, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Example: DVB expansion modules from Metz ( Memento of the original from January 2, 2008 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Example for a digital television from Sharp ( Memento of the original from October 11, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Example of a digital television from technisat
- ↑ heise.de: Example of a digital hard disk recorder from Technisat
- ↑ http://www.satundkabel.de/modules.php?op=modload&name=News&file=article&sid=15843 ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. The ZDF television council approved the further development of its "media library" into a 7-day on-demand offer based on the model of Arte and the BBC on televisions, PCs and mobile devices.
- ↑ Merkel: Online offers from ARD and ZDF require regulation ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
See also
Web links
- Link catalog on the topic of television technology at curlie.org (formerly DMOZ )
