Specifications

Glossary
Term Description
QPSK Quadrature Phase Shift Keying: A modulation technique used to
communicate data over long distances by altering the phase of a
carrier signal according to the four data states. Sometimes known as
quaternary or quadriphase PSK, 4-PSK, or 4-QAM.
RF Radio Frequency.
RS Reed-Solomon coding: An error detection and correction, coding
system. 16 bytes of Reed-Solomon Forward Error Correction code are
appended to the packet before transmission bringing the packet length
to 204 bytes. The 16 bytes are used at the receiving end to correct any
errors. Up to eight corrupted bytes can be corrected.
RLC Run Length Coding: Minimisation of the length of a bit-stream by
replacing repeated characters with an instruction of the form ‘repeat
character x y times’.
RX Receive or Receiver.
SCPC Single Channel Per Carrier. Use of a single signal at a given frequency
and bandwidth. Most often, this is used on broadcast satellites to
indicate that radio stations are not multiplexed as subcarriers onto a
single video carrier, but instead independently share a transponder. It
may also be used on other communications satellites, or occasionally on
non-satellite transmissions
Scrambling Alteration of the characteristics of a television signal in order to prevent
unauthorised reception of the information in clear form.
SDI Serial Digital Interface.
SELV Safety Extra Low Voltage (EN 60950).
STB Set-Top Box: A box that sits on top of a television set and is the interface
between the home television and the cable TV company. New
technologies evolving for set-top boxes are video-on-demand, video
games, educational services, database searches, and home shopping.
The cable equivalent of the IRD.
SFN Single Frequency Network: The SFN technique allows large geographic
areas to be served with a common transmission multiplex. All transmitters
in the network are synchronously modulated with the same signal and
they all radiate on the same frequency. Due to the multi-path capability
of the multi-carrier transmission system (COFDM), signals from several
transmitters arriving at a receiving antenna may contribute
constructively to the total wanted signal. The SFN technique is not only
frequency efficient but also power efficient because fades in the field
strength of one transmitter may be filled by another transmitter.
SNG Satellite News-Gathering.
SNMP Simple Network Management Protocol. A ‘layered’ protocol used in
software applications that facilitates the exchange of management
information between network devices. It is part of the Transmission
Control Protocol/Internet Protocol (TCP/IP) protocol suite. SNMP enables
network administrators to manage network performance and resolve
network problems.
B-10 SBM75e Series Modulator Installation and Operation Manual