About Satellite TV Technology
Satellite television became popular in the 1990’s for homeowners. The satellite dishes were huge, unattractive and expensive units utilized by only true technology fans. Today, a compact satellite dish sits on the roof of most rural homes and many suburban homes alike. Satellite television companies promise to deliver better quality picture and sound and to provide access to more movies and sporting events than cable.
Satellite Television Mechanisms
The television provider is considered the broadcast center. The provider receives the signal from programming sources and beams the signal to satellite subscribers. The satellite dish either owned by the subscriber or leased from the provider picks up the signal and relays it to the interior television receiver. Channels that provide programming for broadcast are considered programming sources. The orbiting satellites receive the signal from the broadcast stations and transmit the signal to Earth.
Signal Encoding
An encoder at the broadcast center converts the programming to the correct size and format for the personal satellite receiver. Irrelevant data and other unnecessary information is deleted from the video frames during the encoding and compression process. A bi-directional frame utilizes data from the closest surrounding frames and interrupts the position and color of the pixels to encode the video signal. The least compression for encoding is required with an intraframe. In a predicted frame, the satellite receiver depends on the most recently displayed intraframe to determine how to display the current frame.
Macroblocking and Pixilating
Macroblocking is an artifact or glitch that appears in the video image. The picture resembles blocks for a brief amount of time. Some people refer to macroblocking as pixilating, although the term is incorrect for television viewing. The pixels on a television are too small for an individual to see. Broadcast channels and centers will distort an image on the screen to deliberately scramble the image or audio for non-subscribers or to block offensive images and language. The Federal Communications Commission passed laws in 2006 to levy fines on television stations for violations involving offensive images and language. Most stations use pixilation to circumvent the large fines.