Ericsson SVP 2000, Справочное руководство, Страница: 162 / 196

Glossary
FTP File Transfer Protocol: A protocol used to transfer files over a
TCP/IP network (Internet, UNIX, etc.). For example, after developing
the HTML pages for a Web site on a local machine, they are
typically uploaded to the Web server, using FTP. Unlike e-mail
programs in which graphics and program files have to be attached,
FTP is designed to handle binary files directly and does not add the
overhead of encoding and decoding the data.
G.703 The ITU-T standard which defines the physical and electrical
characteristics of hierarchical digital interfaces.
GOP Group of Pictures: MPEG video compression works more effectively
by processing a number of video frames as a block. The Ericsson
AB Encoder normally uses a 12 frame GOP; every twelfth frame is
an I frame.
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, drop-down
menus and a movable pointer. The on-screen information is usually
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 up-converted broadcast signal for feeding to the
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 multi-point network at which branch nodes
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 out-of-band messages related to network
operation or mis-operation
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.
EN/LZT 790 0046/1 R1A A-8