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Glossary
B.1
Introduction
This appendix provides a brief explaination of the abbreviations and technical terms used in this
manual
B.2
Abbreviations and Technical Terms
The following table details the glossary.
Table B.1: Glossary
Term
Description
16-QAM
16 Quadrature Amplitude Modulation:
A modulation scheme used for the
transmission of digital data, which modifies the amplitude and phase of
an RF sinusoidal carrier frequency to represent data symbols. 4 different
phases and 4 different amplitudes are used for a total of 16 possible
symbols.
8-PSK
8 Phase Shift Keying:
A modulation scheme used for the transmission of
digital data, which modifies the phase of an RF sinusoidal carrier
frequency to represent data symbols. 8 different phases are used for a
total of 8 possible symbols.
ASI
Asynchronous Serial Interface
. A streaming data format which often
carries an MPEG Transport Stream (MPEG-TS). It is electrically identical to
an SDI signal and is always 270 Mbit/s. There are two transmission formats
commonly used by the ASI interface, the 188 byte format (more
common) and the 204 byte format (optional data included).
baud rate
The rate of transfer of digital data when the data comprises information
symbols that may consist of a number of possible states. Equivalent to bit-
rate when the symbols only have two states (1 and 0). Measured in Baud.
BDC Block
Down-Converter:
A component of a dish antenna that
downconverts the output of a LNA to a suitable frequency to
communicate to an Receiver, Demodulator or IRD (typically L-BAND 950
MHz - 1600 MHz).
BER
Bit Error Rate:
A measure of transmission quality. The number of erroneous
bits received divided by the total number of bits transmitted over a link. It
is generally shown as a negative exponent, (e.g., BER = 10
-7
means that 1
in 10,000,000 bits are in error).
BISS
Basic Interoperable Scrambling System:
A satellite signal scrambling
system developed by the European Broadcasting Union and a
consortium of hardware manufacturers. EBU (Tech3290). Using BISS the
transmission is protected by a 12 digit "session key" that is agreed by the
transmitting and receiving parties. The key is entered into both the
encoder and decoder, this key then forms part of the encryption of the
digital TV signal and only receivers with the correct key will decrypt the
signal.
Bit-rate
The rate of transfer of digital data when the data comprises two logic
states, 1 and 0. Measured in bit/s.
B-2
SBD75e Series Demodulator Installation and Operation Manual