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Glossary
A-10
EN/LZT 790 0023/1 R16A
ITU-T International Telecommunications Union - Telecommunications
Standardization Sector (was CCITT).
JPEG Joint Photographic Experts Group: ISO/ITU standard for
compressing still images. It has a high compression capability.
Using discrete cosine transform, it provides user specified
compression ratios up to around 100:1 (there is a trade-off between
image quality and file size).
kbps
1000 bits per second.
Kbit 1024 bits, usually refers to memory capacity or allocation.
Ku-band The portion of the electromagnetic spectrum, which spans the
frequency range of approximately 12 GHz to 14 GHz. Used by
communications satellites. Preferred for DTH applications because
this range of frequency is less susceptible to interference.
LAN Local Area Network: A network, which provides facilities for
communications within a defined building or group of buildings in
close proximity.
L-band The frequency band from 950 MHz to 2150 MHz, which is the
normal input-frequency-range of a domestic IRD. The incoming
signal from the satellite is down-converted to L-band by the LNB.
LED
Light Emitting Diode.
LNB Low Noise Block Down-Converter: The component of a subscriber
satellite transmission receiving dish which amplifies the incoming
signal and down-converts it to a suitable frequency to input to the
IRD (typically 950 MHz - 1600 MHz).
LO Local Oscillator.
lsb Least significant bit.
Luminance The television signal representing brightness, or the amount of light
at any point in a picture. The Y in YC
R
C
B.
LVDS Low Voltage Differential Signal: LVDS is a generic multi-purpose
Interface standard for high speed / low power data transmission. It
was standardized in ANSI/TIA/EIA-644-1995 Standard (aka RS-
644).
Macroblock A 16x16-pixel area of the TV picture. Most processing within the
MPEG domain takes place with macro blocks. These are converted
to four 8x8 blocks using either frame DCT or field DCT. Four 8 x 8
blocks of luminance data and two (4:2:0 chrominance format), four
(4:2:2) or eight (4:4:4) corresponding 8 x 8 blocks of chrominance
data coming from a 16 x 16 section of the luminance component of
the picture. Macroblock can be used to refer to the sample data and
to the coded representation of the sample values and other data
elements.
Mbps Million bits per second.
MCC Multiplex Control Computer: A component of a System 3000
compression system. The MCC sets up the configuration for the
System 3000 Multiplexers under its control. The MCC controls both
the main and backup Multiplexer for each transport stream.