The satellite televisions first hit the market in the early 1990's. Back then, home dishes were costly and classy metal units that occupied a huge portion available space. During those early years, only those people who were TV fans went an extra mile to meet the cost of mounting in their personal dish. Satellite TV was a bit tedious to procure as compared to normal cable and broadcast TV. Nowadays, you notice compact satellite dishes hovering on rooftops of like every house in the United States. If you happen to take a drive all the way through rural areas away from the reach of the cable companies, you will spot satellite dishes in each and every other house. The major companies providing satellite TV services are attracting in more consumers every day with up to date news, sports as well as latest movie releases from all over the world. Satellite TV offered and continues to offer several solutions to problems linked to broadcast and cable TV. Despite the fact that satellite TV technology is still developing, it has already permeated the hearts of several TV viewers.
Problems with Broadcast TV
Theoretically, satellite TV is far much similar to cable TV. It provides a wireless system for transmitting television programming straight to the house of the viewer. In addition, broadcast television and satellite stations both broadcast programming through a radio signal. Broadcast stations make use of a powerful antenna to send out radio waves to the adjacent area. Thereafter, TV Viewers are capable of picking up the signal by means of a much smaller antenna. However, the major drawback of broadcast TV is its inability to send signals over a wide range. The radio signals that are used to televise are discharged from the broadcasting antenna in a straight line. For the viewer to receive these signals, he/she ought to be in direct line of view of the transmitter.
In addition, radio waves are not obstructed by small obstruction like trees or small buildings however, a large blockage, for instance the Earth, is capable of reflecting these radio waves. Given the probability that the Earth were entirely flat, then a TV viewer may possibly pick up broadcast TV several miles from the source. But since the planet is arched, it ultimately breaks the signal's line of view. The other major setback associated with broadcast TV is that the signal is regularly indistinct, even in the screening area. In order to get a completely apparent signal like as the one in cable, the view need to be as close as possible to the broadcast antenna with no hindrances in the way.
The Satellite TV Solution
With the discovery of Satellite TV, the problem of range and distortion had been solved. In this mode of TV broadcast, the broadcast signals are transmitted from satellites orbiting the Earth. Because satellites are far above the ground in the sky, there are several clients in the line of view. Satellite dishes are used with satellite a TV system which represents specialized form of antennas that have the capability of receiving and transmitting radio signals. The TV satellites are all in geosynchronous orbit; meaning that they stay in a single place in the sky in relation to the Earth. All satellites are launched to the space at about 7,000 mph (11,000 kph), attainment around 22,200 miles (35,700 km) from the earth. According to this speed and height, the satellite is bound to orbit around the planet one time in every 24 hours. This is the same time taken by the earth itself to make one complete rotation. Therefore, the satellite maintains pace according to the movement of our planet. This way, you are required to direct the dish towards the satellite only once, from where the dish picks up the signal without adjustments.
At the hub, this is all the technical part in setting up every satellite TV. But as we will discover in the following section, several steps are involved linking the original encoding source and the final decoding done by the TV set.
Satellite TV System
Earlier on, viewers of satellite TV used their costly dishes to ascertain exceptional programming that wasn't essentially planned for mass viewers. The dish as well as the decoding apparatus provided the viewers with the basic tools required to single out up live feeds and foreign stations among diverse broadcast stations, activities by NASA as several other activities transmitted through satellites.
A number of satellite owners have this personal kind of programming. On the contrary, most satellite TV clients receive their programming from a direct broadcast satellite (DBS) source, for instance DirecTV or DISH Network. The service provider is responsible for selecting programs and then broadcasting them their subscribers as a set package. Fundamentally, the goal of the provider is to convey dozens or even hundreds of channel to your TV in a way that approximates the rivalry of cable TV.
Source: Nice, K. & Harris T. (2011).
Different from earlier programming, the provider's transmit is totally digital, an implication that it has much superior picture as well as sound quality. Earlier on satellite television was transmitted in C-band radio which is in the frequency range of 3.7-gigahertz (GHz) to 6.4-GHz. Currently, Digital broadcast satellite broadcasts programming in the frequency range of 11.7 GHz to 14.5 GHz, also known as the Ku range.
The Components there are five most important components concerned involved during the direct to home (DTH) or direct broadcasting (DBS) satellite system. These are the programming (Encoding) source, the center of broadcast, the satellite, the satellite dish and the receiver or the decoder. The Programming or the encoder refers to the channels that provide programming for onward transmission. The supplier doesn't craft original programming itself; rather it pays other businesses such as ESPN for the permission to televise their content through satellite. Therefore, to some extent, the provider acts in the capacity of a broker between the viewer and the actual programming sources.
On the other hand, the broadcast center refers to the central hub of the whole system. It is at the broadcast center, where the TV provider accepts signals from different programming sources and projects a broadcast signal to satellites in geosynchronous orbit. When the satellite receives the signals from the broadcasting station, they are responsible with rebroadcasting them back to the earth. At this point, the viewer's dish receives the signal from the satellite or multiple satellites and transfers it on to the receiver in the viewer's house. After the receiver receives the signal, its work is to process it (decode) and pass the information to a standard TV.
Satellite TV Signal
Satellite signals contain a pretty extended path to trail prior to their appearance on your TV screen in the form of your much loved TV show. In view of the fact that satellite signals have such premium digital data, it would be impractical to broadcast them with no compression. Compression merely means that avoidable or repetitive information is detached from the signal prior to it is transmission. The signal is restructured following its transmission.
Satellite TV Encoding and Encryption
During encoding at the broadcast center, "the high-quality digital stream of video goes through an MPEG encoder" (Nice & Harris, 2011), which then changes the encoding to MPEG-4 video of the right format and size for the satellite recipient in the house. Encoding works hand in hand with compression to evaluate every video frame and get rid of unnecessary or inappropriate data as well as extend information. This procedure diminishes the general volume of the file. Every frame can be encoded any of the three ways described; as an intraframe, with the total representation of data for the particular frame.
This process offers the slightest compression. Also a frame may be encoded as a predicted frame, whereby information enough to enlighten the satellite receiver on how to present the frame with support on the most newly showed intraframe or predicted frame. Therefore, a predicted frame holds data that only that explains how the image has been altered as of the preceding frame. Finally, a frame may be encoded as a bidirectional frame. This only displays information from the neighboring intraframe or predicated frames. By the use of data obtained from the closest adjacent frames, the receiver interpolates the location and color of all pixels.
This procedure intermittently generates artifacts or glitches in the video picture. In this case, one artifact may be viewed as a macro blocking, in which the liquid picture momentarily softens into blocks. Most frequently, Macro blocking is interchangeably called pixilating, a strictly untrue term which has been acknowledged as jargon for this irritating artifact. Video editors as well as graphic artists use "pixilating" more precisely to refer to the deformation of an image. A TV screen has pixels but on the contrary, they are too small for the human eye to recognize them independently. They are very tiny square of video data that make up the image seen on the TV screen.
The pace of solidity depends on the personality of the programming. For instance, when the encoder is changing a news broadcast, it can additional predicted frames since nearly all of the scene hang about the same place in between subsequent frames. In more fast-paced programming, things transform extremely quickly in between frames thereby prompting the encoder to create more inter-frames (Compression, Encoding & Encryption, 2003).
Encryption and Transmission Following the compression of the video the supplier encrypts it so that other people do not get access to it for free. Encryption distorts the entire digital data to such an extent that the only option is to decrypt it. This data can only be changed into necessary data only if the receiver has bares the right protection keys and decryption algorithm. After the signal is encrypted and compressed it is beamed directly to one of the satellites by the broadcast centre. This signal is picked up and amplified by the satellite with an onboard dish. The signal is then send to another dish which beams it and sends it to earth for viewers to pick up.
On reaching the viewer's hose, the signal is captured by the satellite dish. A satellite dish is simply an exceptional type of antenna intended to center on an exact transmission supply. The average dish has bow- shaped (parabolic) surface and an innermost feed horn. To broadcast a signal, a regulator propels it through the horn, and the dish centers the signal into a moderately thin beam.
The curved dish reflects energy from the feed horn, generating a narrow beam. Information cannot be passed by the dish on the receiving end. It can simply receive it. This dish operates exactly in the opposite way method of the transmitter. When the curve dish is hit by the beam, the disc form reflects the radio signal into its interior onto a specific spot, in the same way a hollow mirror centers light onto a specific spot.
The curved dish focuses incoming radio waves onto the feed horn. In this subject, the dish's feed horn is the point passing the signals onto the equipment that is supposed to receive those signals. In a normal setup, major hindrances between the dish and the satellite do not exist. Thus the dish gets clear signals. In some types of setting, the dish is placed in such a manner that it is required to get signals from more than one satellite at once. With such a setting, the satellites may be placed very close to each other such that even a simple dish with a simple horn can pick signal from these satellites. However, this affects the quality of the signals since the dish is not aimed directly at the satellite in one way or the other. There is a new dish design that uses two or more horns is formulated such that it can pick signals clearly from different satellites since it is usually aimed directly at one or more satellites. When the beams from these different satellites hit the curved dish, reflections are sent at diverse angles such that every horn is hit by a different beam. The basic factor in the feed horn is the LNB or the little noise obstruction down converter. The LNB intensifies the radio signals, which do not usually carry programming, emanating from the dish and sifts the noise out. The LNB passes the intensified, sifted signal into the viewer's house through the satellite receiver.
In the whole satellite TV system, the end component is the receiver which has four major tasks:The receiver requires a good decoder chip so as to unlock the encrypted signal for that programming package. Since the work of the receiver is to de-scramble these signals, the provider can make communications with the chip using the signals from the satellite so as to make the required modifications to its decoding programs. Illegal de-scramblers are dealt with by the provider by sending signals that disrupt them more occasionally.
The receiver converts either the digital MPEG-4 or MPEG-2 signals into an analog set-up that a typical TV can identify. In a place like the United States, the digital signals are converted into the analog "National Television Systems Committee (NTSC)" set-up. Some types of receiver setups and dishes can as well produce an HDTV signal. It removes the particular channels from the bigger satellite signal. When the channels on the receiver are changed, it sends the signal of that particular channel to the television. One is not able to watch one channel from the television and tape another since the receiver gives only one channel at a time. At the same time, it is not possible to watch two different programs on different televisions connected to the same receiver. For someone to do this, they must buy another receiver. The receiver also follows up on pay-per-view programs and sometimes phones a computer to give the billing status at the control center of the provider.
Receivers comprise of several other features too. They can get a programming plan signal from the eservice provider and give this message in a programming guide that can be onscreen. While most receivers possess a parental lock-out alternative, others have video recorders that are digitally (DVRs). These can allow someone to record television on a hard drive or put live television on pause. The features of the receiver are simple an added advantage to the technological features of satellite TV. Satellite TVs are becoming a common consumers' investment given its movie-quality sound and pictures. Picture qualities have been improved ant the selection of channels has been expanded by the use of the digital cable.
These have demonstrated that they are capable of providing stiff competition to the providers of satellites. The war on TV is getting tougher between digital cable and satellite technologies and between the service providers. Satellites and digital cables have become a common feature in many homes despite the fact that they were once considered as luxuries. At the same time, providers are bundling televisions with Internet and phone services to present healthy competition deals and attract more customers.