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Kullanım Kılavuzu
ATLANTA Xtrend - ET9000
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
complex, 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
appropriate 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 designated 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
composite of three source signals called Y, U and V (together referred to as YUV)
with sync pulses. 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
Stands for Digital Satellite Equipment Control. It is a special communication
protocol for use between a satellite receiver and a device such as a multi-dish
switch or a small dish antenna rotor. DiSEqC was developed by European
satellite provider Eutelsat, which now acts as the standards agency for the
protocol.
