Television reception
The television receiver is the processing of television signals of one or more output devices for video and audio for television . It is used for the consumption of television programs and television reception depends on the receivable signals (channel, location and time dependent) and the function of the end devices.
Each transmission of signals is encoded and must be decoded at the receiver. This coding should not be confused with the encryption of signals that only very few transmitters operate (e.g. soldier transmitters, pay TV).
Signals can only be received if you have set an active television channel (for satellites: transponder channel ) and the television set supports the television signal . Furthermore, there are different qualities in the processing of the signals, e.g. B. High Definition Television (high-resolution picture), provided that the broadcasters provide this quality.
Signals
In the early years and especially in urban areas, television signals were transmitted via antennas ( aerial television ), and later also via cable systems or via satellite . When transmitting via antennas, one speaks of terrestrial television , while the actual transmission is wireless (non-terrestrial). In the case of cable television, the transmission path is exclusively wired. There have been no more terrestrial broadcasts in Switzerland since 2019.
Satellite television is provided through television satellites . Satellite television also requires a parabolic antenna and a receiver, which must also be aligned with the desired satellite depending on the station. Most of the channels in Central Europe are received via satellite, followed by cable TV. Today only a very small number of stations transmit via antenna. The signals are sent in a certain television standard and either digitally or analogue , whereby digital television offers a much better picture and sound quality. Antenna TV is very inexpensive, and satellite TV is the most expensive due to the equipment required.
These types of transmission are in turn divided according to their standard:
Linear television
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Analog television (obsolete in Central Europe)
- Aerial television
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Digital television
- DVB-T : digital broadcasting in terrestrial television (digital video broadcasting - terrestrial)
- DVB-C : Digital broadcasting via cable (Digital Video Broadcasting - Cable)
- DVB-S : Digital broadcasting via satellite (Digital Video Broadcasting - Satellite)
- DVB-H : Digital broadcasting for handheld devices (Digital Video Broadcasting - Handhelds)
- DMB : Digital multimedia broadcasting (Digital Multimedia Broadcasting)
- IPTV, Internet TV, P2PTV: Internet Protocol Television (Internet Protocol Television)
Non-linear (parallel) television
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Internet TV
- IPTV : IP television in a closed network
- Internet TV : IP TV in the free internet
- P2PTV : IP peer-to-peer television in the free Internet
Output devices
Depending on the broadcaster, it is necessary to connect certain devices such as satellite receivers and / or digital receivers to the television set. When receiving television signals on computers , you need either a TV card or, for IPTV, an Internet connection to an Internet service provider and a dial-up line , e.g. B. DSL , or a WLAN .
Reception is only possible with if the output devices can process them. Special components in the television set or additional devices such as decoders , cable modems or satellite receivers are therefore necessary. For pay TV , another device and possibly a chip (for authorization) is required.
The test image is the most suitable means of checking the reception , here color scales and a continuous tone are sent out. Test images replace a normal television program outside of broadcast time.
The television reception does not always correspond to the quality of the transmission, for example colored pictures can be received with a black-and-white television , although the signal carries information for the color transmission system; the same applies to Dolby broadcasts without the end device supporting these signals.
Finally, the signals can be presented in different ways by the television set, e.g. B. in a different image format .