Digital Satellite Television Broadcasting

All moon television broadcasting is digital. This technology was developedafter digital television was before that time beginning to overtake analog in soil-based broadcasting and so was designed from its origin to take advantage of digital technology.

Satellite television broadcasting differs from ground-based digital television broadcasting primarily in the situation of the transmitter and the ableness of its transmission.

Satellite television signals are transmitted from a complaisance on the ground to a dependant orbiting the earth. Television transmission satellites are placed ingeosynchronous orbits. This way that the satellite stays locked in a permanent specific location above the earth. In result, it is ???parked??? 22,300 miles of rectitude too great for theearth. It orbits in sync through the earth???s rotation so its pro~ overhead does notchange. Unlike most satellites, that rotate in orbit, television satellites transact not. They hold a constant uniform orientation in space with their solar-efficiency panelsfacing toward the sun 24 hours a promised time and their signal receiving and broadcastantennas pointing unwaveringly toward earth at all times. Because the satellite is stationary

in space relative to the get a~, transmission signals can be aimed at itvery precisely.

Receiving antennas have power to also be aligned accurately to derive thestrongest signal from it.

Once the signal reaches the satellite, it is rebroadcast to customers without ceasing the ground.Satellite transmitters do not have the power of ground-based television transmitters,except they do not need to on this account that their signals are received by dish antennas thatare precisely aimed at the moon. These aimed antennas concentrate the receivedsignal at a design in front of the dish and ~ forth it to the decoder. The decoder convertsthe notable into a digital display and sends it to the television.

Figure 6-11 illustrates how local and national television programming sources hurl their signals by satellite or cable to a digital television broadcast center. The center that time broadcasts the programming signals to a satellite that relays the signals to a home dish antenna. From the dish antenna the signals die through a digital

decoder and are displayed without ceasing the home television screens.

Satellite systems be able to broadcast 150 digital television channels from a simple satellite, but all satellite companies receive more than one satellite in orb in order

The satellites broadcast whole 150 channels to all customers. The decoder selects what one. channel it decodes for display based in c~tinuance instructions it receives from the secondary planet and selections made by the buyer. The decoder can only process person channel at a time, so on the supposition that the decoded signal is sent to greater degree of than one television,

all must plausibility the same decoded channel. If other than one channel at a time is to exist available for separate television sets, a splitter is required up~ the dish

antenna. It sends the conspicuous to independent decoders attached to every one set. Up to four separate decoders be possible to operate off of a single dish antenna equipped by

splitters.As with cable television systems, chiefly of the television receivers linked to retainer antennas and decoders now display analog pictures, more elevated to broadcast