- 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.
A frequency at which a closed-loop system can acquire and track a signal. See lock-in range.
Industry:Telecommunications
A frequency band deliberately left vacant between two channels to provide a margin of safety against mutual interference.
Industry:Telecommunications
A frequency source that meets national standards for accuracy and operates without the need for calibration against an external standard. Note: Examples of primary frequency standards are hydrogen masers and cesium beam frequency standards.
Industry:Telecommunications
A frequency standard in which a specified hyperfine transition of electrons in rubidium-87 atoms is used to control the output frequency. Note: A rubidium standard consists of a gas cell, which has an inherent long-term instability. This instability relegates the rubidium standard to its status as a secondary standard.
Industry:Telecommunications
A frequency standard that does not have inherent accuracy, and therefore must be calibrated against a primary frequency standard. Note: Secondary standards include crystal oscillators and rubidium standards. A crystal oscillator depends for its frequency on its physical dimensions, which vary with fabrication and environmental conditions. A rubidium standard is a secondary standard even though it uses atomic transitions, because it takes the form of a gas cell through which an optical signal is passed. The gas cell has inherent inaccuracies because of gas pressure variations, including those induced by temperature variations. There are also variations in the concentrations of the required buffer gases, which variations cause frequency deviations.
Industry:Telecommunications
A frequency that (a) is used by all military units that are equipped to operate at that frequency or in the band in which that frequency lies and (b) is also used internationally by survival-craft stations and survival-craft equipment.
Industry:Telecommunications
A frequency that is allocated and assigned by a competent authority to a specific user for a specific purpose. 2. The frequency, or frequency range, assigned to a station by the Commission and specified in the instrument of authorization. See assigned frequency.
Industry:Telecommunications
A frequency that is assigned for usual use on a particular circuit. 2. The first-choice frequency that is assigned to a fixed or mobile station for radiotelephone communications.
Industry:Telecommunications
A frequency that is maintained to the known accuracy of an accepted reference frequency standard. Note: Current uncertainty among international standards is approximately 1 part in 1014 as of 1995.
Industry:Telecommunications
A frequency that is not to be deliberately jammed by friendly forces, usually during a specified period.
Industry:Telecommunications
