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IX. Glossary
8PSK
8-PSK is usually the highest order PSK constellation deployed. With more than 8
phases, the error-rate becomes too high and there are better, though more com
-
plex, modulations available such as quadrature amplitude modulation (QAM).
Although any number of phases may be used, the fact that the constellation
must usually deal with binary data means that the number of symbols is usually
a power of 2 – this allows an equal number of bits-per-symbol.
CAM
Conditional Access Module is an electronic device, usually incorporating a slot for
a smart card, which equips an Integrated Digital Television or set-top box with the
appropriated hardware facility to view conditional access content that has been
encrypted using a conditional access system. They are normally used with direct
broadcast satellite (DBS) services.
Composite
Video
Composite video is the format of an analog television (picture only) signal before
it is combined with a sound signal and modulated onto an RF carrier. Composite
video is often designed by the CVBS acronym, meaning “Color, Video, Blank and
Sync”. In German (with PAL being a German invention by Telefunken’s Walter
Bruch) the abbreviation FBAS (Farbe - Bild - Austastung - Synchron) means the
same. It is usually in standard formats such as NTSC, PAL, and SECAM. It is a com -
posite of three source signals called Y, U and V (together referred to as YUV) with
sync pluses. Y represents the brightness or luminance of the picture and includes
synchronizing pulses, so that by itself it could be displayed as a monochrome
picture. U and V represent hue and saturation or chrominance; between them
they carry the color information. They are first modulated on two orthogonal
phases of a color carrier signal to form a signal called the chrominance. Y and UV
are then combined. Since Y is a baseband signal and UV has been mixed with a
carrier, this addition is equivalent to frequency-division multiplexing.
Conditional
Access
System
Several companies provide competing Conditional Access Systems; Irdeto Access,
Nagravision, Conax, Viaccess, Verimatrix and NDS are among the most Commonly
used CAS systems.
DiSEqC
Standards for Digital Satellite Equipment Control. It is a special communication
protocol for use between a satellite receiver and a devise such as a multi-dish
switch or a small dish antenna rotor. DiSEqC was developed by European satel-
lite provider Eutelsat, which now acts as the standards agency for the protocol.
EPG
Electronic Program Guide is a digital guide to scheduled broadcast television or
radio programs, typically displayed on-screen with functions allowing a viewer to
navigate, select, and discover content by time, title, channel, genre, etc. by use of
their remote control, a keyboard, or other input devices such as a phone keypad.
Content can also be scheduled for future recording by a personal video recorder
(PVR). The on-screen information may be delivered by a dedicated channel or
assembled by the receiving equipment from information sent by each program
channel.