- 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 basic principle of optics, that no passive optical system can increase the quantity L/n2, where L is the radiance of a beam and n is the local refractive index. Note: "Conservation of radiance" was formerly called "conservation of brightness" or the "brightness theorem. "
Industry:Telecommunications
A basic parameter affecting the password length needed to provide a given degree of security. Note 1: Password length parameters are related by the expression P = LR/S, where P is the probability that a password can be guessed in its lifetime, L is the maximum lifetime a password can be used to log in to a system, R is the number of guesses per unit of time, and S is the number of unique algorithm-generated passwords (the password space. ) Note 2: The degree of password security is determined by the probability that a password can be guessed in its lifetime.
Industry:Telecommunications
A basic group of Pulse Code Modulation (PCM) channels assembled by Time Division Multiplex. In the United States it usually consists of 24 channels at 1. 544 Mbs.
Industry:Telecommunications
A barrier or enclosure that attenuates an electrostatic field.
Industry:Telecommunications
A bank-issued number that can be used in place of cash for Internet transactions. Note: The use of digital cash allows a vendor to check the validity of the transaction by contacting the issuing bank, but it does not allow additional information to be obtained about the buyer. Synonyms e-cash, electronic cash.
Industry:Telecommunications
A band of frequencies, between specified limits, that a circuit, such as a filter or telephone circuit, does not transmit. Note 1: Frequencies above the lower limit and below the upper limit are not transmitted, i.e., are not allowed to pass. Note 2: The limiting frequencies are those at which the transmitted power level increases to a specified level, usually 3 dB below the maximum level, as the frequency is decreased or increased from that at which the transmitted power is a minimum. Note 3: The difference between the limits is the stopband bandwidth, usually expressed in hertz.
Industry:Telecommunications
A ball that can be rotated about its center and that is used as an input device, e.g., to position a cursor. Synonym control ball.
Industry:Telecommunications
A balanced transmission line, in a multipair cable, having equal conductor resistances per unit length, equal impedances from each conductor to earth, and equal impedances to other lines.
Industry:Telecommunications
A balanced transformer used to perform a conversion between 4-wire and 2-wire operation. Note 1: For example, a 4-wire circuit may, by means of a 4-wire terminating set, be connected to a 2-wire telephone set. Also, a pair of 4-wire terminating sets may be used to introduce an intermediate 4-wire loop into a 2-wire circuit, in which loop repeaters may be situated to amplify signals in each direction without positive feedback and oscillation. Note 2: Four-wire terminating sets have been largely supplanted by resistance hybrids.
Industry:Telecommunications
A "mark" that has the same polarity as the previous "mark" in the transmission of alternate mark inversion (AMI) signals. Note: In some transmission protocols, AMI violations are deliberately introduced to facilitate synchronization or to signal a special event.
Industry:Telecommunications
