Annex A

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 YCRCB.

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.

MCPC

Multiple Channels Per Carrier.

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