Article contributed by Mr. Upendra Kumar Singh, Assistant Professor, Faculty of Technology and Computer Applications
A satellite television (TV) system some times refers as direct broadcast satellite (DBS) is the systems in which the subscribers, or end users, receive signals directly from geostationary satellites. A geostationary satellite is a satellite which is orbiting around the earth in equatorial plane, placed at an altitude of approximately 35,800 kilometers, these satellites revolves in the same direction the earth rotates (west to east).
The microwave frequencies are used to broadcast the signals in digital format. DBS is the successor of direct-to-home (DTH) satellite services. DBS and DTH service are provided by a number of companies throughout the world. In India Tatasky, Dish TV, DD Free Dish, Airtel digital TV,d2h, Sun Direct are some vendors. Now a days satellite internet services are also very much popular, which is provided by some of these vendors and can be purchased by a user for a monthly fee in addition to, or instead of, DBS TV service. Satellite-based TV and Internet services are popular in rural areas where conventional cable service is not available. Satellite TV is also preferred by urban and suburban users who are not satisfied with the quality or quantity of TV programming available on conventional cable.
Satellite TV Components and Working
There are five major components which are involved in a Satellite TV or direct broadcasting (DBS) satellite system as shown in figure: the programming source, the broadcast center, the satellite, the satellite dish and the receiver.
- Programming sources are simply the channels that provides the content for broadcast. The provider doesn’t create original programming itself; it pays other companies (for example Sony , Colors etc in india) for the right to broadcast their content via satellite. In this way, the provider is kind of like a broker between viewer and the actual programming sources. (Cable TV companies work on the same principle.)
- The broadcast center is the central hub of the system. At the broadcast center, the TV provider receives signals from various programming sources and transmits a broadcast signal to satellites in geostationary orbit.
- The satellites receive the signals from the broadcast station and rebroadcast them to Earth.
- The viewer’s dish picks up the signal from the satellite (or from multiple satellites) and passes it on to the receiver (set top box) in the viewer’s house.
- The receiver receives the signal and after processing the signal it passes the signal to the standard TV set.
Advantages of Satellite TV
- Easy installation of
- Superior picture quality.
- Small size parabolic dishes are required with a small set top box for signal reception.
- Easy un- installation and reinstallation to another place.
- Higher bandwidths and data rates are attainable
- It provides a wide range of channels and services, often to areas that are not serviced by terrestrial or cable providers.
- Pay only for the channels you watch.
Drawbacks of satellite TV
- The process of launching the satellites into orbits is very costly.
- Propagation delay is on higher side.
- The equivalent isotropically radiated power (EIRP) and bandwidth are important parameters which are needed to be designed carefully.
- L-I. Lundström, “Understanding Digital Television: An Introduction to DVB Systems with Satellite, Cable, Broadband and Terrestrial TV Distribution,” Taylor & Francis Ltd, 2006.
- B. Evans et al., “Integration of satellite and terrestrial systems in future multimedia communications,” in IEEE Wireless Communications, vol. 12, no. 5, pp. 72-80, Oct. 2005.
- UKEssays. (November 2018). A Introduction To Satellite Television. Retrieved from https://www.ukessays.com/essays/media/a-introduction-to-satellite-television-media-essay.php?vref=1