E4
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Antenna
Adevice that collects and radiates electromagnetic waves. Includes a satellite dish and
abroadband antenna.
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Forward Error Correction(FEC)
Asystem 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)
Afrequency to which a carrier frequency is shifted as an intermediate step in transmission or
reception.
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Low Noise Block(LNB) Downconverter
Alow noise microwave amplifier and converter which downconverts a range of frequencies
to IF range.
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Packet Identifier(PID)
Aset of numbers that idenitifies transport stream packets containing data from a single data stream.
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Polarisation
Characteristic of an electromagnetic wave determined by the orientation of the electricfield 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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Service
Achannel to which a decoder or TV is tuned.
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Transponder
An automatic device that receives, amplifies and retransmits a signal on a different frequency.