Glossary
GB3
•
Antenna
A device that collects and radiates electromagnetic waves. Includes a satellite dish and
abroadband antenna.
•
Forward Error Correction(FEC)
A system of error control for data transmission.
•
Frequency
The number of cycles or events per one second, which is expressed in the unit of Hertz(Hz).
•
Intermediate Frequency(IF)
A frequency to which a carrier frequency is shifted as an intermediate step in transmission or
reception.
•
Low Noise Block(LNB) Downconverter
A low noise microwave amplifier and converter which downconverts a range of frequencies
to IF range.
•
Packet Identifier(PID)
A set of numbers that idenitifies transport stream packets containing data from a single data stream.
•
Polarisation
Characteristic of an electromagnetic wave determined by the orientation of the electricfield vector.
•
Quaternary Phase Shift Keying(QPSK)
Phase-shift keying in which four different phase angles are used.
•
Service
A channel to which a decoder or TV is tuned.
•
Transponder
An automatic device that receives, amplifies and retransmits a signal on a different frequency.
Glossary
English (HSMM30GB) 10/30/02 10:05 AM Page 6