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25.01.2007
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Antenna
A device that collects and radiates electromagnetic waves, includes a satellite dish and a
broadband antenna.
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Forward Error Correction (FEC)
A system of error control for data transmission.
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Frequency
The number of cycles or events per one second, which is expressed in the unit of Hertz(Hz).
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Intermediate Frequency (IF)
A frequency to which a carrier frequency is shifted as an intermediate step in transmission or
reception.
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Low Noise Block (LNB) down converter
A low noise microwave amplifier and converter which down converts a range of frequencies to
IF range.
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Packet Identifier (PID
)
A set of numbers that identifies transport stream packets containing data from a single data
stream.
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Polarization
Characteristic of an electromagnetic wave determined by the orientation of the electric field
vector.
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Quaternary Phase Shift Keying (QPSK)
Phase-shift keying in which four different phase angles are used.
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Transponder
Equipment in a satellite which receives a single uplink channel from a satellite earth station,
amplifies it, converts the frequency and changes the polarization, then it back to Earth.
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Transport Stream
The bit stream formed prior to transmission of signals by combining the video, audio
data streams of one service. It consists of fixed length packets of 188 bytes of data.
Glossary
