Satellite television is a fairly recent technology that allows a household to receive television content via transmission from a communications satellite. The essential components are the satellite itself - a multimillion-dollar expenditure for the broadcast company - and the home satellite dish, something the average consumer can acquire for about fifty dollars, or even receive for free as part of their service subscription package.
Why bounce information off of a satellite? Traditional broadcast stations are limited by the curvature of the earth and by obstacles that interfere with "line of sight" reception, causing lack of signal or distortion. Satellite TV overcomes those obstacles with ease.
In the early days of the technology, people used huge, motorized backyard dishes to chase satellites across the sky and pull in free programming, but this dropped off sharply when providers began to encrypt their signals. Now there are several "direct broadcast satellite" (DBS) or "Direct-To-Home" providers that make it easy for the average consumer to use a small stationary satellite dish to receive subscription programming from satellites which use geosynchronous orbits to remain in one place in the sky, relative to the Earth.
These satellite TV companies provide a high-quality digital signal carrying both national "turnaround channels" -- including popular pay channels like HBO and Showtime and free content like Lifetime, MTV, and ESPN - as well as local affiliates for networks like ABC or PBS. These two types of programming are compressed, encrypted, and then aimed at the satellites from separate uplink centers on the ground.
The most popular direct broadcast satellite providers in the United States are the Dish Network and DirecTV. They provide a parabolic receiving dish, which focuses the incoming signal onto a "feedhorn", which then passes it on to a "low noise blockdown converter", which filters out unwanted noise. The signal then gets passed to the satellite receiver inside the house, which decrypts the digital signal, converts it to an analog or HDTV signal, and keeps track of the usage of pay-per-view programs
The receiver only allows the viewing of one channel at a time; to watch or record other channels requires additional receivers. However, the receivers are highly customizable and often include the popular "digital video recorder" technology which allows digital recording, rewinding and pausing during live programming.
Satellite direct
No comments:
Post a Comment