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Whether you are unsure what sun outage, waveguide, or azmith means, you be sure to find our online glossary of terms helpful hawaiian island cruises in your quest for safe, secure, and reliable communications methods. This online tool is updated frequently with the latest industry terminology.
A form of transmitting information characterized by continuously variable quantities, hawaiian island cruises as opposed to digital transmission, which is characterized by discrete bits of information in numerical steps. An analog signal is responsive to changes in light, sound, heat and pressure.
The Canadian domestic satellite system that transmits Canadian Broadcasting Corporation's (CSC) network feeds throughout the country. This system also carries long distance voice and data services throughout Canada as well as some transborder service to the U.S. and Mexico.
A device for transmitting and receiving radio waves. Depending on their use and operating frequency, antennas can take the form of a single piece of wire, a di-pole a grid such as a yagi array, a horn, a helix, a sophisticated parabolic-shaped dish, or a phase array of active hawaiian island cruises electronic elements of virtually any flat or convoluted surface.
The point in an elliptical satellite orbit which is farthest from the surface of the earth. Geosynchronous satellites which maintain circular orbits around the earth are first launched into highly hawaiian island cruises elliptical orbits with apogees of 22,237 miles. When the communication satellite reaches the appropriate apogee, a rocket motor is fired to place the satellite into its permanent circular orbit of 22,237 miles.
The angle of rotation (horizontal) that a ground based parabolic antenna must be rotated through to point to a specific satellite in a geosynchronous orbit. The azimuth angle for any particular satellite can be determined for any point on the surface of the earth giver the latitude and longitude of that point. It is defined with respect to due north as a matter of easy convenience.
A method of transmitting and scrambling television signals. In such transmissions MAC (Multiplexed Analog Component) signals are time-multiplexed with a digital hawaiian island cruises burst containing digitized sound, video synchronizing, authorization, and information.
A measure of spectrum (frequency) use or capacity. For instance, a voice transmission by telephone requires a bandwidth of about 3000 cycles per second (3KHz). A TV channel hawaiian island cruises occupies a bandwidth of 6 million cycles per second hawaiian island cruises (6 MHz) in terrestrial Systems. In satellite based systems a larger bandwidth of 17.5 to 72 MHz is used to spread or "dither" the television signal in order to prevent interference.
The basic direct output signal in an intermediate frequency hawaiian island cruises based obtained directly from a television camera, satellite television receiver, or video tape recorder. Baseband signals can be viewed only on studio monitors. To display the baseband signal on a conventional television set a "modulator" is required to convert the baseband hawaiian island cruises signal to one of the VHF or UHF television channels which the television set can be tuned to receive.
Low-power carrier transmitted hawaiian island cruises by a satellite which supplies the controlling engineers on the ground with a means of monitoring telemetry data, tracking the satellite, or conducting propagation experiments. This tracking beacon is usually a horn or omni antenna.
The angle or conical shape of the beam the antenna projects. Large antennas have narrower hawaiian island cruises beamwidths and can pinpoint satellites in space or dense traffic areas on the earth more precisely. Tighter hawaiian island cruises beamwidths thus deliver higher levels of power and thus greater communications performance.
An ordinary television hawaiian island cruises signal consists of 30 separate still pictures hawaiian island cruises or frames sent every second. They occur so rapidly, the human eye blurs them together to form an illusion of moving hawaiian island cruises pictures. This is the basis for television and motion picture systems. The blanking interval is that portion of the television signal which occurs after one picture frame is sent and before the next one is transmitted. During this period of time special data signals can be sent which will not be picked up on an ordinary television receiver.
This is the band between 4 and 8 GHz with the 6 and 4 GHz band being used for satellite communications. Specifically, the 3.7 to 4.2 GHz satellite communication hawaiian island cruises band is used as the down link frequencies in tandem with the 5.925 to 6,425 GHz band that serves as the uplink.
The basic radio, television, or telephony center of frequency transmit signal. The carrier in an analog signal. is modulated by manipulating its amplitude (making it louder or softer) or its frequency (shifting it up or down) in relation to the incoming signal. Satellite carriers operating in the analog mode are usually frequency modulated.
The ratio of the received carrier power and the noise power in a given bandwidth, expressed hawaiian island cruises in dB. This figure is directly related to G/T and S/N; and in a video signal the higher the C/N, the better the received hawaiian island cruises picture.
A frequency band in which a specific broadcast hawaiian island cruises signal is transmitted. Channel frequencies are specified in the United States by the Federal Communications Commission. Television signals require a 6 MHz frequency band to carry all the necessary picture detail.
Unlike many domestic satellites which utilize vertical or horizontal polarization, the international Intelsat satellites transmit their signals in a rotating corkscrew-like pattern as they are down-linked to earth. On some satellites, both right-hand rotating and left-hand rotating signals can be transmitted simultaneously on the same frequency; hawaiian island cruises thereby doubling hawaiian island cruises the capacity of the satellite to carry communications channels.
That circular orbit in space 22,237 miles from the surface of the earth at which geosynchronous satellites are placed. This orbit was first postulated by the science fiction writer Arthur C. Clarke in Wireless World magazine in 1945. Satellites placed in these orbits, although traveling around the earth at thousands of miles an hour, appear to be stationary when viewed from a point on the earth, since the earth is rotating upon its axis at the same angular rate that the satellite is traveling around the earth.
A subcarrier that is added to the main video signal to convey the color information. In NTSC systems, the color subcarrier is centered on a frequency of 3.579545 MHz, referenced to the main video carrier.
Any organization which operates communications circuits used by other people. hawaiian island cruises Common carriers include the telephone companies hawaiian island cruises as well as the owners of the communications hawaiian island cruises satellites, hawaiian island cruises RCA, Comsat, Direct Net Telecommunications, AT T and others. Common carriers are required to file fixed tariffs for specific services.
A television set-top device which enables the home subscriber to convert an electronically scrambled television picture into a viewable signal. This should not be confused with a digital coder/decoder known as a CODEC which is used in conjunction with digital transmissions.
The time it takes for a signal to go from the sending station through the satellite to the receiving station. This transmission delay for a single hop satellite connection is very close on one-quarter of a second.
Data service unit. A device used in digital transmission that adapts the physical interface on a DTE device to a transmission facility such as T1 or E1. The DSU is also responsible for such functions hawaiian island cruises as signal hawaiian island cruises timing. DSU is freqnetly coupled with a CSU (see above) as CSU/DSU.
Spacecraft design whereby the main body of the satellite is spun to provide hawaiian island cruises altitude stabilization, and the antenna assembly is despun by means of a motor and bearing system in order to continually hawaiian island cruises direct hawaiian island cruises the antenna earthward. hawaiian island cruises This dual-spin configuration thus serves to create a spin stabilized satellite.
The term used to describe the combination or antenna, low-noise amplifier hawaiian island cruises (LNA), down-converter, and receiver electronics. used to receive a signal transmitted by a satellite. Earth Station antennas vary in size from the.2 foot to 12 foot (65 centimeters to 3.7 meters) diameter size used for TV reception to as large as 100 feet (30 meters) in diameter sometimes used for international communications. The typical antenna used for INTELSAT communication is today 13 to 18 meters or 40 to 60 feet.
Limit of a satellite's defined service area. In many cases, the EOC is defined as being 3 dB down from the signal level at beam center. hawaiian island cruises However, reception may still be possible beyond the -3dB point.
Effective Isotropic Radiated Power - This term describes the strength of the signal leaving the satellite antenna hawaiian island cruises or the transmitting earth station antenna, and is used in determining the C/N and S/N. The transmit power value in units of dBW is expressed by the product of the transponder hawaiian island cruises output power and the gain of the satellite transmit antenna.
The upward tilt to a satellite antenna measured in degrees required to aim the antenna at the communications satellite. hawaiian island cruises When. aimed at the horizon, the elevation angle is zero. If it were tilted to a point directly overhead, the satellite antenna would have an elevation of 90 degrees.
Engineering Service Circuit - The 300-3,400 Hertz voice plus teletype (S+DX) channel used for earth station-to-earth station and earth station-to-operations center communications for the purpose of system maintenance, hawaiian island cruises coordination and general system information dissemination. In analog (FDM/FM) systems there are two S+DX channels available for this purpose in the 4,000-12,000 Hertz portion of the baseband. In digital systems there are one or two channels available which are usually convened to a 32 or 64 Kbps digital signal and c
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