Xtrend ET9000, User Manual

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VIIII. 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.
Dolby Digital Dolby Digital is the common version containing up to six
discrete channels of sound. The most elaborate mode in
common usage involves five channels for normal-range
speakers (20 Hz - 20,000 Hz) (right front, center, left front,
right rear and left rear) and one channel (20 Hz - 120 Hz
allotted audio) for the subwoofer driven low-frequency
effects. Mono and stereo modes are also supported. AC-3
supports audio sample-rates up to 48 kHz.
* Dolby Digital
* DD (an abbreviation for Dolby Digital, often combined
with channel count; for instance, DD 2.0, DD 5.1)
* AC-3 (Audio Codec 3, Advanced Codec 3, Acoustic
Coder 3.