- Industry: Telecommunications
- Number of terms: 29235
- Number of blossaries: 0
- Company Profile:
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.
Of a network, the schematic configuration that reflects the network's function, use, or implementation without regard to the physical interconnection of network elements.
Industry:Telecommunications
Of a periodic wave, the number of suitable units of angular measure between a point on the wave and a reference point. Note 1: The reference point may be a point on another periodic wave. The waves may be plotted on a suitable coordinate system, such as a Cartesian plot, with degrees or other angular measure usually plotted on the abscissa and amplitude on the ordinate. Usually, at least one full cycle of each wave is plotted, with 360&176; (2 radians) encompassing one full cycle. The reference points may be any significant instants on the waves, such as where they cross the abscissa axis. Note 2: The use of angular measure to define the relationship between a periodic wave and a reference point is derived from the projection of a rotating vector onto the real axis of an Argand diagram. Note 3: The value of the phase angle of a point on the wave is the point on the abscissa that corresponds to the point on the wave. Note 4: The phase angle of a vector may be written as M, where M is the magnitude of the vector and is the phase angle relative to the specified reference.
Industry:Telecommunications
Of a periodic wave, the sinusoidal component, i.e., Fourier component, having the lowest frequency. Note: Every periodic waveform may be expressed as the summation of the fundamental and its harmonics. For example, a square wave may be expressed as the summation of sine waves equal in frequency to the fundamental and all odd harmonics, each frequency having an appropriate amplitude and phase. A pure sinusoidal wave has only one component, i.e., the fundamental.
Industry:Telecommunications
Of a periodic, varying phenomenon, e. G. , an electrical signal or electromagnetic wave, any distinguishable instantaneous state of the phenomenon, referred to a fixed reference or another periodic varying phenomenon. Note 1: Phase, i.e., phase time (frequently abbreviated simply to "phase" in informal usage,) can be specified or expressed by time of occurrence relative to a specified reference. Note 2: The phase of a periodic phenomenon can also be expressed or specified by angular measure, with one period usually encompassing 360&176; (2 radians. ) Note 3: Phase may be represented (a) in polar coordinates by M, where M is the magnitude and is the phase angle, and (b) in Cartesian coordinates, i.e., an Argand diagram, as (a + jb,) where a is a real component and b is an imaginary component such that tan = (b/a,) where is the phase angle, and the magnitude, M, is (a2 + b2) ½ 2. A distinguishable state of a phenomenon. 3. That period of time during which a specified function occurs in a sequential list of functions.
Industry:Telecommunications
Of a radio emission, the distribution of power or energy as a function of frequency.
Industry:Telecommunications
Of a received stream of framed data, the process by which incoming frame alignment signals, i.e., distinctive bit sequences, are identified, i.e., distinguished from data bits, permitting the data bits within the frame to be extracted for decoding or retransmission. Note: The usual practice is to insert, in a dedicated time slot within the frame, a noninformation bit that is used for the actual synchronization of the incoming data with the receiver. Synonym framing.
Industry:Telecommunications
Of a recording medium, erasing or overwriting all data in such a manner that it cannot be recovered, even by extraordinary, e.g., laboratory, means. Note: Sanitizing is distinguished from simply "deleting" or "erasing" data. For example, a software-based deletion command may simply mark a file or block of data to the effect that it may be overwritten during a subsequent "save" of different data. Until such a save is performed, the deleted data may be recovered, sometimes by the simple expedient of executing a software command. Likewise, digital data, for example, may be "erased," from a magnetic recording medium, but still be recoverable if subjected to laboratory techniques that can identify residual magnetism left after the erasure.
Industry:Telecommunications
Of a refractive or reflective optical element, the straight line that is coincident with the axis of symmetry of the surfaces. Note: The optical axis of a system is often coincident with its mechanical axis, but it need not be, e.g., in the case of an off-axis parabolic reflector used to transmit signals to, or receive signals from, a geosynchronous satellite. 2. In a lens element, the straight line which passes through the centers of curvature of the lens surfaces. 3. In an optical system, the line formed by the coinciding principal axes of the series of optical elements. 4. In an optical fiber, synonym fiber axis.
Industry:Telecommunications
Of a satellite orbiting the Earth, an orbit in which the projection of the satellite's position on the (Earth's) equatorial plane revolves in the direction opposite that of the rotation of the Earth.
Industry:Telecommunications
Of a satellite orbiting the Earth, the point in the orbit at which the gravitational centers of the satellite and Earth are closest to one another.
Industry:Telecommunications
