Satellite TV Signal
planet signal have a pretty foresightful route to follow before they come along on your TV sieve in the form of your best-loved TV show . Because orbiter signals hold such high - quality digital data point , it would be impossible to beam them withoutcompression . contraction simply means that unnecessary or repetitious information is removed from the signal before it is conduct . The signal is reconstructed after transmission .
Standards of Compression
Satellite TV expend a special eccentric of telecasting file compression standardize by the Moving Picture Experts Group ( MPEG ) . With MPEG compression , the supplier is able to transmit importantly more channels . There are presently five of these MPEG standards , each serve a unlike purpose . DirecTV and DISH internet , the two major satellite TV providers in the United States , once usedMPEG-2 , which is still used to stash away movies onDVDsand for digital cable television ( DTV ) . With MPEG-2 , the TV supplier can reduce the 270 - Mbps stream to about 5 or 10 Mbps ( depending on the type of programming ) .
Now , DirecTV and DISH internet employ MPEG-4 compaction . Because MPEG-4 was to begin with designed for streaming video in small - blind media likecomputers , it can encode more efficiently and allow a greater bandwidth than MPEG-2 . MPEG-2 remains the prescribed standard for digital TV compression , but it is better equipped to analyze static images , like those you see on a talking show or newscast , than moving , dynamic images . MPEG-4 can raise a better picture of active images through usance of spatial ( infinite ) and secular ( sentence ) compression . This is whysatelliteTV using MPEG-4 contraction provides high definition of quick - moving objects that constantly change place and direction on the CRT screen , like in a basketball game game .
In the next part , we will see how orbiter telly signals are encoded for transmission .
