- 産業: Telecommunications
- Number of terms: 29235
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ATIS is the leading technical planning and standards development organization committed to the rapid development of global, market-driven standards for the information, entertainment and communications industry.
In an FM receiver, the phenomenon that results in less noise when an unmodulated carrier is present than when there is no carrier present. Note: Quieting is expressed in dB.
Industry:Telecommunications
In an FM receiver, the effect produced when the desired-signal gain begins to limit the desired signal, and thus noise limiting (suppression. ) Note: FM threshold effect occurs at (and above) the point at which the FM signal-to-noise improvement is measured.
Industry:Telecommunications
In an electronic device, of a subassembly or component therein (e.g. Circuit card,) the act or process of removing and replacing the subassembly or component without first powering down the device. Note: Hot swapping of components in devices or environments not designed to support such practice may result in damage to the component or device, or may pose a spark hazard even if the primary power has been removed. And, in some computing devices, hot swapping may not be appropriate because new components may be recognized only during boot-up.
Industry:Telecommunications
In an electromagnetic waveguide, the exchange of power among modes. Note: In a multimode optical fiber, mode coupling reaches statistical equilibrium, i.e., equilibrium mode distribution, after the equilibrium length has been traversed.
Industry:Telecommunications
In an electrical system, an unwanted current that flows in a conductor connecting two points that are nominally at the same potential, i.e., ground, but are actually at different potentials. Note 1: For example, the electrical potential at different points on the surface of the Earth can vary by hundreds of volts, primarily from the influence of the solar wind. Such an occurrence can be hazardous, e. G. , to personnel working on long grounded conductors such as metallic telecommunications cable pairs. Note 2: A ground loop can also exist in a floating ground system, i.e., one not connected to an Earth ground, if the conductors that constitute the ground system have a relatively high resistance, or have, flowing through them, high currents that produce a significant voltage ("I•R") drop. Note 3: Ground loops can be detrimental to the operation of the electrical system.
Industry:Telecommunications
In an electrical circuit, the condition that exists when the inductive reactance and the capacitive reactance are of equal magnitude, causing electrical energy to oscillate between the magnetic field of the inductor and the electric field of the capacitor. Note 1: Resonance occurs because the collapsing magnetic field of the inductor generates an electric current in its windings that charges the capacitor and the discharging capacitor provides an electric current that builds the magnetic field in the inductor, and the process is repeated. Note 2: At resonance, the series impedance of the two elements is at a minimum and the parallel impedance is a maximum. Resonance is used for tuning and filtering, because resonance occurs at a particular frequency for given values of inductance and capacitance. Resonance can be detrimental to the operation of communications circuits by causing unwanted sustained and transient oscillations that may cause noise, signal distortion, and damage to circuit elements. Note 3: At resonance the inductive reactance and the capacitive reactance are of equal magnitude. Therefore, L = 1/C, where = 2f, in which f is the resonant frequency in hertz, L is the inductance in henrys, and C is the capacity in farads when standard SI units are used. Thus,
Industry:Telecommunications
In an automatic cellular mobile system, the interface between the radio system and the public switched telephone network. Note: The MSC performs all signaling functions that are necessary to establish calls to and from mobile stations.
Industry:Telecommunications
In an automated radio, the device that commands the radio transmitter and receiver, and that performs processes, such as automatic link establishment, channel scanning and selection, link quality analysis, polling, sounding, message store and forward, address protection, and anti-spoofing.
Industry:Telecommunications
In an antenna, the part of the radiated energy from the feed that does not impinge on the reflectors.
Industry:Telecommunications
In an antenna system, a hybrid junction used as a directional coupler. Note: The loss through a hybrid coupler is usually 3 dB.
Industry:Telecommunications
