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Direct-broadcast Satellite
Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna commonly referred to as a satellite dish and a low-noise block downconverter. A satellite receiver then decodes the desired television program for viewing on a television set. Receivers can be external set-top boxes, or a built-in television tuner. Satellite television provides a wide range of channels and services. It is usually the only television available in many remote geographic areas without terrestrial television or cable television service. Modern systems signals are relayed from a communications satellite on the X band (8–12 GHz) or Ku band (12–18 GHz) frequencies requiring only a small dish less than a meter in diameter. The first satellite TV systems were an obsolete type now known as television receive-only. These ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog Signal
An analog signal or analogue signal (see spelling differences) is any continuous signal representing some other quantity, i.e., ''analogous'' to another quantity. For example, in an analog audio signal, the instantaneous signal voltage varies continuously with the pressure of the sound waves. In contrast, a digital signal represents the original time-varying quantity as a sampled sequence of quantized values which imposes some bandwidth and dynamic range constraints on the representation. The term ''analog signal'' usually refers to electrical signals; however, mechanical, pneumatic, hydraulic and other systems may also convey or be considered analog signals. Representation An analog signal uses some property of the medium to convey the signal's information. For example, an aneroid barometer uses rotary position as the signal to convey pressure information. In an electrical signal, the voltage, current, or frequency of the signal may be varied to represent the informatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molniya Orbit
A Molniya orbit ( rus, Молния, p=ˈmolnʲɪjə, a=Ru-молния.ogg, "Lightning") is a type of satellite orbit designed to provide communications and remote sensing coverage over high latitudes. It is a highly elliptical orbit with an inclination of 63.4 degrees, an argument of perigee of 270 degrees, and an orbital period of approximately half a sidereal day. The name comes from the '' Molniya'' satellites, a series of Soviet/Russian civilian and military communications satellites which have used this type of orbit since the mid-1960s. The Molniya orbit has a long dwell time over the hemisphere of interest, while moving very quickly over the other. In practice, this places it over either Russia or Canada for the majority of its orbit, providing a high angle of view to communications and monitoring satellites covering these high-latitude areas. Geostationary orbits, which are necessarily inclined over the equator, can only view these regions from a low angle, hampe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Earth directly above the Equator, the plane of the satellite's orbit is the same as the Earth's equatorial plane, and the satellite's orbital inclination is 0°. The general case for a circular orbit is that it is tilted, spending half an orbit over the northern hemisphere and half over the southern. If the orbit swung between 20° north latitude and 20° south latitude, then its orbital inclination would be 20°. Orbits The inclination is one of the six orbital elements describing the shape and orientation of a celestial orbit. It is the angle between the orbital plane and the plane of reference, normally stated in degrees. For a satellite orbiting a planet, the plane of reference is usually the plane containing the planet's equator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can also be used for any other celestial body that is roughly spherical. In spatial (3D) geometry, as applied in astronomy, the equator of a rotating spheroid (such as a planet) is the parallel (circle of latitude) at which latitude is defined to be 0°. It is an imaginary line on the spheroid, equidistant from its poles, dividing it into northern and southern hemispheres. In other words, it is the intersection of the spheroid with the plane perpendicular to its axis of rotation and midway between its geographical poles. On and near the equator (on Earth), noontime sunlight appears almost directly overhead (no more than about 23° from the zenith) every day, year-round. Consequently, the equator has a rather stable daytime temperature throu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geostationary Orbit
A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular geosynchronous orbit in altitude above Earth's equator ( in radius from Earth's center) and following the direction of Earth's rotation. An object in such an orbit has an orbital period equal to Earth's rotational period, one sidereal day, and so to ground observers it appears motionless, in a fixed position in the sky. The concept of a geostationary orbit was popularised by the science fiction writer Arthur C. Clarke in the 1940s as a way to revolutionise telecommunications, and the first satellite to be placed in this kind of orbit was launched in 1963. Communications satellites are often placed in a geostationary orbit so that Earth-based satellite antennas do not have to rotate to track them but can be pointed permanently at the position in the sky where the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streaming Television
Streaming television is the digital distribution of television content, such as TV shows, as streaming media delivered over the Internet. Streaming television stands in contrast to dedicated terrestrial television delivered by over-the-air aerial systems, cable television, and/or satellite television systems. History Up until the 1990s, it was not thought possible that a television programme could be squeezed into the limited telecommunication bandwidth of a copper telephone cable to provide a streaming service of acceptable quality, as the required bandwidth of a digital television signal was around 200 Mbit/s, which was 2,000 times greater than the bandwidth of a speech signal over a copper telephone wire. Streaming services were only made possible as a result of two major technological developments: MPEG ( motion-compensated DCT) video compression and asymmetric digital subscriber line (ADSL) data transmission. The first worldwide live-streaming event was a radio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cord-cutting
In broadcast television, cord-cutting refers to the pattern of viewers, referred to as cord-cutters, cancelling their subscriptions to multichannel television services available over cable or satellite, dropping pay television channels or reducing the number of hours of subscription TV viewed in response to competition from rival media available over the Internet. This content is either free or significantly cheaper than the same content provided via cable. As a market trend, a growing number of "cord cutters" do not pay for subscription television in favor of some combination of broadband Internet and IPTV, digital video recorders, digital terrestrial television and/or free-to-air satellite television broadcasts. A related group, the cord-nevers, have never used commercial cable for television service, relying on internet sources from the start. A number of purely internet television services, part of the wider IPTV concept, have emerged to cater to these groups. In the third ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pay Television
Pay television, also known as subscription television, premium television or, when referring to an individual service, a premium channel, refers to subscription-based television services, usually provided by multichannel television providers, but also increasingly via digital terrestrial, and streaming television. In the United States, subscription television began in the late 1970s and early 1980s in the form of encrypted analog over-the-air broadcast television which could be decrypted with special equipment. The concept rapidly expanded through the multi-channel transition and into the post-network era. Other parts of the world beyond the United States, such as France and Latin America have also offered encrypted analog terrestrial signals available for subscription. The term is most synonymous with premium entertainment services focused on films or general entertainment programming such as, in the United States, Cinemax, Epix, HBO, Showtime, and Starz, but such servic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free-to-view
Free-to-view (FTV) is a term used for audiovisual transmissions that are provided free without any form of continual subscription . It differs from free-to-air (FTA) in that the program is encrypted. Free-to-view vs. free-to-air The free-to-view system contrasts with free-to-air (FTA), in which signals are transmitted in the clear, without encryption, and can be received by anyone with a suitable receiving dish antenna and DVB-compliant receiver (although these services can include proprietary encrypted data services such as an EPG that is only available to reception equipment made for, or authorised by, the FTA broadcaster). Free-to-view services are broadcast encrypted and can only be viewed with reception equipment that includes a suitable conditional-access module and viewing card, in the same way as a pay-TV satellite service. However, the FTV service viewing card is not subject to a continuing subscription payment for viewing the service's channels and may be available ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free-to-air
Free-to-air (FTA) services are television (TV) and radio services broadcast in unencrypted form, allowing any person with the appropriate receiving equipment to receive the signal and view or listen to the content without requiring a subscription, other ongoing cost, or one-off fee (e.g., pay-per-view). In the traditional sense, this is carried on terrestrial radio signals and received with an antenna. FTA also refers to channels and broadcasters providing content for which no subscription is expected, even though they may be delivered to the viewer/listener by another carrier for which a subscription is required, e.g., cable television, the Internet, or satellite. These carriers may be mandated (or OPT) in some geographies to deliver FTA channels even if a premium subscription is not present (providing the necessary equipment is still available), especially where FTA channels are expected to be used for emergency broadcasts, similar to the 1-1-2 (112) emergency service provi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star One C2
Star One C2 is a Brazilian communications satellite. It was launched on 18 April 2008 22:17 UTC by an Ariane 5ECA carrier rocket, as part of a dual-payload launch with Vinasat-1. It was built by Thales Alenia Space, based on the Spacebus-3000B3 satellite bus. It is operated by Star One, a subsidiary of Embratel, and Bolivarsat. Overview On June 2, 2008, Star One C2 replaced BrasilSat B4 in the task of broadcasting the main Brazilian TV network channels. This position, at 70.0° W, had been once occupied by Brasilsat B1. Since December 2008, Star One C2 transmits the Claro TV pay TV Pay television, also known as subscription television, premium television or, when referring to an individual service, a premium channel, refers to subscription-based television services, usually provided by multichannel television providers, b ... package. The service is supplied by Embratel and Claro companies and operates in Ku band. See also * Star One (satellite operator) * Star O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
