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, 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. Dolby Digitalsupports audio sample-rates up to 48 kHz.
* Dolby Digital * ![]() ![]() ![]() |