- 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.
Protocol control information located at the end of a protocol data unit (PDU. )
Industry:Telecommunications
Providing electronic key via over-the-air rekeying, over-the-air key transfer, or cooperative key generation.
Industry:Telecommunications
Public specifications that are maintained by an open, public consensus process to accommodate new technologies over time and that are consistent with international standards.
Industry:Telecommunications
Pulse-code modulation in which an analog signal is sampled and the difference between the actual value of each sample and its predicted value, derived from the previous sample or samples, is quantized and converted, by encoding, to a digital signal. Note: There are several variations of differential pulse-code modulation.
Industry:Telecommunications
Pulsing in which a direct-current pulse train is produced by interrupting a steady signal according to a fixed or formatted code for each digit and at a standard pulse repetition rate. Note: Dial pulsing originated with rotary mechanical devices integrated into telephone instruments, for the purpose of signaling. Subsequent applications use electronic circuits to generate dial pulses. Synonym pulsing.
Industry:Telecommunications
Punched or magnetic tape containing key. Printed key in tape form is referred to as a key list.
Industry:Telecommunications
Quadrature modulation in which the two carriers are amplitude modulated. 2. In analog communications, the representation (i.e., transmission) of digital information by encoding bit sequences of fixed, specified length (number of bits,) and representing these bit sequences as a function of (a) the amplitude of an analog carrier; or (b) a phase shift of the analog carrier with respect to the phase that represented the preceding bit sequence, and where the permissible phase shift is an integral multiple of /2 radians (90°, or one-quarter unit interval); or (c) both. Note 1: The name quadrature originates from the stipulation that a phase shift, when required, must be an integral multiple of p/2 radians, i.e., one-quarter of a cycle (unit interval, or baud. ) Note 2: A representative QAM table is presented below. If the baud (carrier) rate is 1200 Hz (the usual case in modems used on conventional telephone lines,) this QAM scheme permits transmission of a data rate of 9600 b/s, which is the product of the baud rate and the number of permissible phase-amplitude states. Bit Sequence Represented Normalized Carrier Amplitude Relative Phase Shift (Degrees) 000 1/2 0 (0°) 001 1 0 (0°) 010 1/2 /2 (90°) 011 1 /2 (90°) 100 1/2 (180°) 101 1 (180°) 110 1/2 3 /2 (270°) 111 1 3 /2 (270°) Any continuous bit stream may be represented as a combination of the eight permissible bit sequences in the above table, and transmitted as such. Note 3: According to mathematical theory, there is no limit to the data rate that may be supported by, or associated with, a given baud rate in a perfectly stable, noiseless transmission environment. In practice, the governing factors are the amplitude (and consequently, phase) stability, and the amount of noise present, in both the terminal equipment and the transmission medium (carrier frequency, or communication channel) involved. Nor does the permitted relative (incremental) phase shift necessarily have to be a multiple of /2 radians, but of course the name "quadrature" would not apply if any other minimum phase shift were specified or permitted.
Industry:Telecommunications
Radiance per unit wavelength interval at a given wavelength, expressed in watts per steradian per unit area per wavelength interval.
Industry:Telecommunications
Radiant power emitted into a full sphere, i.e., 4 sr (steradians,) by a unit area of a source, expressed in watts per square meter. Synonym radiant exitance.
Industry:Telecommunications
Radiant power emitted into a full sphere, i.e., 4 sr (steradians,) by a unit area of a source, expressed in watts per square meter. Synonym radiant exitance.
Industry:Telecommunications
