Telecommunications — page 61 of 85

Telecommunications terms

6001. Pulse Repetition Frequency (PRF) The amount of time between successive pulses, or bursts, of electromagnetic energy that is transmitted by a radar.
6002. pulse repetition rate The number of pulses per unit time.
6003. pulse rise time See rise time.
6004. pulse string Synonym pulse train.
6005. pulse stuffing See bit stuffing.
6006. pulse train A series of pulses having similar characteristics. Synonym pulse string.
6007. Pulse Width Same as Pulse Length; the linear distance in range occupied by an individual pulse from a radar.
6008. pulse-address multiple access (PAMA) The ability of a communication satellite to receive signals from several Earth terminals simultaneously and to amplify, translate, and relay the signals…
6009. pulse-amplitude modulation (PAM) Modulation in which the amplitude of individual, regularly spaced pulses in a pulse train is varied in accordance with some characteristic of the…
6010. pulse-code modulation (PCM) Modulation in which a signal is sampled, and the magnitude (with respect to a fixed reference) of each sample is quantized and digitized for transmission…
6011. pulse-duration modulation (PDM) Modulation in which the duration of pulses is varied in accordance with some characteristic of the modulating signal.
6012. pulse-frequency modulation (PFM) Modulation in which the pulse repetition rate is varied in accordance with some characteristic of the modulating signal.
6013. pulse-interval modulation See pulse-position modulation.
6014. pulse-length modulation Deprecated synonym for pulse-duration modulation.
6015. pulse-position modulation (PPM) Modulation in which the temporal positions of the pulses are varied in accordance with some characteristic of the modulating signal.
6016. pulse-repetition-rate modulation Synonym pulse-frequency modulation.
6017. pulse-time modulation (PTM) The general class of pulse-code modulation in which the time of occurrence of some characteristic of the pulsed carrier is varied with respect to some…
6018. pulse-width modulation (PWM) Deprecated synonym for pulse-duration modulation.
6019. pulsed FM systems A spread spectrum system in which the RF carrier is modulated with a fixed period and fixed duty cycle sequence.
6020. pulsing In telephony, the transmission of address information to a switching office by means of pulses, i.e., signals, that originate from the subscriber, i.e.
6021. pump frequency The frequency of an oscillator used to provide sustaining power to a device, such as a laser or parametric amplifier, that requires rf or optical power.
6022. Pumping Mechanical transfer of fluids.
6023. pure binary numeration system See binary notation.
6024. Purge To remove information that has no further value from a file, usually according to a records retention schedule
6025. purging Rendering stored information unrecoverable by laboratory attack. [INFOSEC-99]
6026. Push Refers to the player and the dealer having the same total. Usually the player's bet is returned when there is a push.
6027. push-down file See last-in first-out.
6028. push-to-talk (PTT) operation In telephone or two-way radio systems, that method of communication over a speech circuit in which the talker is required to keep a switch operated while…
6029. push-to-type operation In telegraph or data transmission systems, that method of communication in which the operator at a station must keep a switch operated in order to send…
6030. pushbutton dialing Dialing in which (a) pushbuttons or keys are used to actuate and connect audible tone oscillators to a line, (b) each button or key corresponds to a…
6031. PVC Permanent virtual circuit. A network connection with a static route defined in advance, usually by manual setup.
6032. pW Precipitable Water - measure of the depth of liquid water at the surface that would result after precipitating all of the water vapor in a vertical column…
6033. PWM Abbreviation for pulse-width modulation, which is a deprecated synonym for pulse-duration modulation.
6034. PWP Abbreviation for permanent wilting point.
6035. pWp0 Abbreviation for picowatts, psophometrically weighted, measured at a zero-dBm transmission level point. See dBm(psoph), psophometer.
6036. pX Abbreviation for peak envelope power (of a radio transmitter).
6037. QA Quality Assurance.
6038. QAM Abbreviation for quadrature amplitude modulation.
6039. QC Quality Control.
6040. QCIF Abbreviation for quarter common intermediate format.
6041. QOS Quality of Service. The performance level defined for a data communications system.
6042. QPSK Abbreviation for quadrature phase-shift keying.
6043. QRS (1) Quartz Resonant Sensor. (2) Quick Reaction Software.
6044. QRSS Abbreviation for quasi-random signal source.
6045. QRTS Abbreviation for quasi-random test signal.
6046. QRW Abbreviation for quasi-random word.
6047. Quad One quadrillion Btu. (1,000,000,000,000,000 Btu)
6048. quadded cable A cable formed of multiples of quads, paired and separately insulated, and contained under a common jacket.
6049. QUADRANT The District of Columbia is divided into four quadrants: Northwest, Northeast, Southwest and Southeast.
6050. quadratic profile Synonym parabolic profile.
6051. Quadrature The component of the complex signal that is 90 degrees out of phase with the inphase component.
6052. quadrature amplitude modulation (QAM) Quadrature modulation in which the two carriers are amplitude modulated. 2. In analog communications, the representation (i.e.
6053. quadrature modulation Modulation using two carriers out of phase by 90° and modulated by separate signals.
6054. quadrature phase-shift keying (QPSK) Phase-shift keying in which four different phase angles are used. Note: In QPSK, the four angles are usually out of phase by 90°.
6055. quadriphase Synonym quadrature phase-shift keying.
6056. quadruple diversity In radio communication, diversity transmission and reception in which four independently fading signals are used.
6057. quadruply clad fiber A single-mode optical fiber that has four claddings. Note 1: Each cladding has a refractive index lower than that of the core.
6058. Quality Assurance (QA) (QA) The process of identifying problems in service delivery, designing activities to overcome these problems, and following up to ensure that no new problems…
6059. quality control (QC) A management function whereby control of the quality of (a) raw materials, assemblies, produced materiel, and components, (b) services related to…
6060. quality factor In a reactive circuit, the ratio of the reactance in ohms divided by the resistance in ohms.
6061. Quality of Service (QoS) The performance level defined for a data communications system.
6062. Quantization A process in which a continuous signal is converted to a series of points at discrete levels.
6063. quantization error Synonym quantizing distortion.
6064. quantization level In the quantization process, the discrete value assigned to a particular subrange of the analog signal being quantized.
6065. quantization noise Synonym quantizing noise.
6066. quantized feedback In a digital feedback loop, the digital signal that is fed back. Note 1: Several forms of analog-to-digital converters contain a quantized feedback loop…
6067. quantizing distortion Distortion that results from the quantization process. Synonym quantization error.
6068. quantizing levels In digital transmission, the number of discrete signal levels transmitted as the result of signal digitization.
6069. quantizing noise Noise caused by the error of approximation in quantization. Note: Quantizing noise is dependent on the particular quantization process used and the…
6070. quantum efficiency In an optical source or detector, the ratio of the number of output quanta to the number of input quanta.
6071. quantum noise Noise attributable to the discrete and probabilistic nature of physical phenomena and their interactions.
6072. quantum-limited operation Synonym quantum-noise-limited operation.
6073. quantum-noise-limited operation Operation wherein the minimum detectable signal is limited by quantum noise. Synonym quantum-limited operation.
6074. quarter common intermediate format (QCIF) A video format defined in ITU-T Recommendation H.261 that is characterized by 176 luminance pixels on each of 144 lines, with half as many chrominance…
6075. quartz clock A clock containing a quartz oscillator that determines the accuracy and precision of the clock.
6076. quartz oscillator An oscillator in which a quartz crystal is used to stabilize the frequency. Note: The piezoelectric property of the quartz crystal results in a nearly…
6077. quasi-analog signal A digital signal that has been converted to a form suitable for transmission over a specified analog channel.
6078. quasi-analog transmission Transmission in which a special-purpose modulator is used to convert digital signals into an analog form suitable for transmission over an analog…
6079. quasi-associated mode of signaling A limited case of the nonassociated mode of signaling in which the path taken by a message through the signaling network is predetermined and fixed at a…
6080. quasi-lossless compression In video and multimedia applications, the bit-rate reduction of an image signal, by an algorithm that recognizes the high degree of correlation…
6081. quasi-random signal (QRS) See QRS.
6082. quaternary phase-shift keying Synonym quadrature phase-shift keying.
6083. quaternary signal A digital signal having four significant conditions.
6084. Query A request for identification of a set of assets, expressed in terms of a set of criteria, which the identified item must satisfy.
6085. query call In adaptive high-frequency (HF) radio, an automatic-link-establishment (ALE) call that requests responses from stations having connectivity to the…
6086. queue A system where if a realm is overloaded, subsequent players trying to log on will be queued up in a first come first serve basis and allowed to log on…
6087. queue traffic A series of outgoing or incoming calls waiting for service. 2. In a store-and-forward switching center, the outgoing messages awaiting transmission at the…
6088. queuing The process of entering elements into or removing elements from a queue.
6089. queuing delay In a switched network, the time between the completion of signaling by the call originator and the arrival of a ringing signal at the call receiver.
6090. queuing theory The theoretical study of waiting lines, expressed in mathematical terms--including components such as number of waiting lines, number of servers, average…
6091. quiet zone With respect to the rf spectrum, an area in which emissions are restricted for the purpose of minimizing possible impact on the operations of radio…
6092. quieting In an FM receiver, the phenomenon that results in less noise when an unmodulated carrier is present than when there is no carrier present.
6093. quincunx sampling 1. In a digital video system, a sampling structure where the luminance and color-difference samples are generated from pixels arranged on one of two…
6094. R interface For a basic rate access in an ISDN environment, the interfacing specifications covering pre-ISDN standards (e.g., EIA-232C).
6095. R/C Abbreviation for radio control, radio service.
6096. raceway Within a building, an enclosure, i.e., channel, used to contain and protect wires, cables, or bus bars.
6097. rack A frame upon which one or more units of equipment are mounted. Note: DOD racks are always vertical.
6098. racon See radar beacon.
6099. RAD Radiation Absorbed Dose. The basic unit of an absorbed dose of ionizing radiation.
6100. radar Acronym for RAdio Detection And Ranging; a radio device or system for locating an object by means of ultrahigh-frequency radio waves reflected from the…