Advantech L-Band Satellite Modulator Installation And Operation Manual Download

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Glossary

Term

Description

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).

kbit/s

1000 bits per second.

Kbit

1024 bits, usually refers to memory capacity or allocation.

Ku-band

ITU-defined frequency range from 12 GHz to 18 GHz. Used by
communications satellites, 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

ITU-defined frequency range from 950 MHz to 2150 MHz. The normal
input-frequency-range of a domestic IRD. The incoming signal from the

satellite is down-converted to L-band by the LNB.

LCD

Liquid Crystal Display

. A thin, flat display device made up of any number

of colour or monochrome pixels arrayed in front of a light source or
reflector. Often utilized in battery-powered electronic devices because it
uses very small amounts of electric power.

LED

Light Emitting Diode.

A semiconductor diode that emits light when an

electric current is applied in the forward direction of the device.

Link Budget

The accounting of all of the gains and losses from the transmitter,
through the medium (free space, cable, waveguide, fiber, etc.) to the
receiver in a telecommunication system. It accounts for the attenuation
of the transmitted signal due to propagation, as well as the antenna

gains, feedline and miscellaneous losses. Randomly varying channel
gains such as fading are taken into account by adding some margin
depending on the anticipated severity of its effects. The amount of
margin required can be reduced by the use of mitigating techniques
such as antenna diversity or frequency hopping.

LNA Low-Noise

Amplifier:

A component of a dish antenna that amplifies the

weak signals received from a satellite (or microwave transmitter). It is
often located very close to, or on, the antenna (immediately behind the

feed horn) so that further losses, due to the signal travelling down the
feed line, are minimised.

LNB

Low-Noise Block Down-Converter:

A combination of Low Noise Amplifier

(LNA) and a Block Down-Converter (BDC) usually mounted on a dish
antenna to enable it to amplify and downconvert the received signal to
a suitable frequency to communicate to a Receiver, Demodulator or IRD
(typically L-BAND 950 MHz - 1600 MHz).

LNBF

Low-Noise Block Down-Converter and Feed:

A combination of Low Noise

Amplifier, Block Down-Converter and Feed, mounted on a dish antenna.

LO Local

Oscillator.

LVDS

Low Voltage Differential Signal:

LVDS is a generic multi-purpose Interface

standard for high speed / low power data transmission. It was
standardised in ANSI/TIA/EIA-644-1995 Standard (aka RS-644).

M&C

Monitor and Control.