Glossary |
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Terms |
Descriptions |
| Backhaul: |
In television, the circuits (usually satellite or telephone) used to transmit or “haul” a signal back from a remote site to a network headquarters, television station or other central location for processing before being distributed. MultiChoice receives various signals from across the world for the DStv platform i.e. BBC, CNN, etc. These signals are backhaul signals. |
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| Bandwidth: |
Refers to the amount of data a cable or transponder can carry. |
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| C-band : |
Satellite services operating on a much lower frequency than Ku-band. It was used mainly for signal distribution in the past, but more powerful transponders can also be used for direct-to-home purposes. A C-band footprint is normally much bigger than a Ku-band footprint. |
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| Compress: |
This is a digital picture manipulator effect where the picture is made proportionally smaller.
Pictures are analyzed looking for redundancy and repetition and unnecessary data is discarded. The technique was primarily developed for digital transmission but has been adopted as a means of handling digital video in computers and reducing the storage demands for digital VTRs. Compression can be at either a set rate or a variable rate. Also known as Bit Rate Reduction (BRR).
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| Conditional access: |
Digital television signals can be scrambled in such a way that they cannot be understood by a conventional decoder. Only when unscrambled by a special system can the original pictures be seen by the viewer. By controlling the operation of the de-scrambling system through the use of a pre-paid access card, or by a transmitted code, the broadcaster can control access to a particular channel or service.
Conditional access can be used to control many things from pay-per-view subscription through to target viewing areas. The ATSC specification, at press time, was not complete.
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| Distribution quality : |
The level of quality of a television signal from the station to its viewers. For digital television this is approximately 19.39 Mbps. |
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| Downlink: |
Earth station used to receive signals from satellite. |
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| DTH : |
Direct-to-home. CD quality audio to video broadcast system. |
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| DVB-H: |
Digital video broadcast via handheld technology. The means through which television can be delivered to handsets. |
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| Electronic Programming Guide (EPG) : |
An application that provides an on-screen listing of all programming and content that an interactive television service subscriber or digital television viewer has available to them. |
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| Encryption: |
The process of coding data so that a specific code or key is required to restore the original data. In broadcast, this is used to make transmissions secure from unauthorised reception as is often found on satellite or cable systems. |
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| Enhancements : |
Producers add these to interactive and digital television, as well as other digital content to enhance programme material. Examples are supplementary text and graphics that add more depth and richness, or links to reach a website, as is done using TV Crossover Links.
In analog, the vertical blanking interval (VBI) is used to broadcast enhancements, while in digital, the enhancements are part of the ATSC MPEG-2 stream. Enhancements can be created using industry-standard tools and technologies, like HTML and the ECMA Internet Scripting.
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| Footprint: |
Area on earth within which a satellite’s signal can be received. |
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| Format conversion : |
The process of both encoding/decoding and resampling digital rates to change a digital signal from one format to another. |
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| Intelsat : |
International Telecommunications Satellite organisation. The agency that operates networks of satellites for international transmission. |
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| Interactive television: |
A combination of television with interactive content and enhancements. Interactive television provides better, richer entertainment and information, blending traditional TV-watching with the interactivity of a personal computer.
Programming can include richer graphics, one-click access to websites through TV Crossover Links, electronic mail and chats, and online commerce through a back channel.
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| IPTV : |
Television transmission through internet protocol. |
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| iTV : |
Interactive television, allowing you to interact with content provided through your television set. |
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| Ku-band: |
The DStv platform for southern Africa is transmitted via the Ku-band satellite system. It operates at a much higher frequency than C-band and has a much smaller footprint with more power, hence the requirement for smaller satellite dishes. |
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| Transponder: |
Satellite transmitter / receiver that picks up signals transmitted from earth, translates them into new frequencies and amplifies them before re-transmitting them back to earth. |
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