Annex A
GUI | Graphical User Interface: The use of pictures rather than just words |
| to represent the input and output of a program. A program with a |
| GUI runs under a windowing system and has a screen interface |
| capable of displaying graphics in the form of icons, |
| menus and a movable pointer. The |
| controlled / manipulated by a mouse or keyboard. |
HDTV | High Definition Television. |
HPA | High Power Amplifier: Used in the signal path to amplify the |
| modulated and |
| uplink antenna. |
HSYNC | Horizontal (line) SYNCs. |
HTTP | HyperText Transfer Protocol. The fundamental protocol used on the |
| Internet for transmission of WEB pages and other data between |
| servers and PCs |
HU | Height Unit |
Hub | A device in a |
| interconnect. |
ICAM | Integrated Conditional Access Module: Embedded in the IRD and |
| responsible for descrambling, plus packet filtering and reception. It |
| also contains the physical interface to the subscriber’s viewing card. |
ICMP | Internet Control Message Protocol. ICMP messages, delivered in IP |
| packets, are used for |
| operation or |
IGMP | Internet Group Management Protocol. IGMP is a protocol used to |
| manage multicasts on the Internet. For a host (receiver unit) to |
| receive a multicast, it needs to transmit IGMP "join" messages on |
| the right format. Three versions exist. IGMPv2 is common today but |
| IGMPv3 is the next step. |
IDU | Indoor unit |
IEC | International Electrotechnical Committee. |
IF | Intermediate Frequency: Usually refers to the 70 MHz or 140 MHz |
| output of the Modulator in cable, satellite and terrestrial transmission |
| applications. |
Interframe Coding | Compression coding involving consecutive frames. When |
| consecutive frames are compared, temporal redundancy is used to |
| remove common elements (information) and arrive at difference |
| information. |
| individually incomplete and relate to other adjacent frames, they |
| cannot be edited independently. |
Intraframe Coding | Compression coding involving a single frame. Redundant |
| information is removed on a per frame basis. All other frames are |
| ignored. Coding of a macroblock or picture that uses information |
| only from that macroblock or picture. Exploits spatial redundancy by |
| using DCT to produce I frames; these are independent frames and |
| can be edited. |
EN/LZT 790 0005 R1A |