The Illustrated Dictionary of Electronics - Loscha

462 multiplex telegraphy • multiprogrammingSubcarrieroscillatorMixerRFamplifierfTuned tomfOutModulatorReactancemodulatedoscillatorPoweramplifierIn+12 VAF amp.AF amp.Outputmultiplier amplifierSubsidiaryinputMaininputmultiplexing, 1.multiplex telegraphy 1. A system of wire telegraphyin which two or more messages are sent simultaneouslyin one or both directions. 2. Asystem of radiotelegraphy in which two or moremessages can be sent simultaneously on thesame carrier wave.multiplex telephony 1. A system of wire telephonyin which two or more messages can besent simultaneously in one or both directionsover the same line. 2. A system of radiotelephonyin which two or more messages can be sent simultaneouslyon the same carrier wave.multiplication 1. The arithmetic process wherebya certain factor is added to itself the number oftimes indicated by another factor (the multiplier).2. A method of increasing a quantity, magnitude,or rate by some desired factor. See, for example,FREQUENCY MULTIPLIER and VOLTAGE MUL-TIPLIER.multiplier 1. See FREQUENCY MULTIPLIER.2. See VOLTAGE MULTIPLIER. 3. A circuit ordevice for performing arithmetic multiplication.4. See VOLTMETER MULTIPLIER.multiplier amplifier A frequency-multiplying amplifier(such as a doubler, tripler, or quadrupler),whose output circuit is tuned to an integral multipleof the input frequency. Compare STRAIGHT-THROUGH AMPLIFIER.multiplier phototube See PHOTOMULTIPLIERTUBE.multiplier prefix A prefix that, when affixed to thename of a quantity (e.g., Hertz and byte) indicatesthe amount, usually a power of 10 or a power of2, by which that quantity is to be multiplied. Alsocalled prefix and prefix multiplier. See PREFIXEStable in Appendix B. Also see, for example,GIGA-, KILO-, MEGA-, MICRO-, MILLI-, NANO-,and PICO-.multiplier probe 1. A resistor-type test probe for avoltmeter, which increases the range of the meterand, therefore, acts as a voltmeter multiplier. 2. Avoltage-multiplier type of test probe for a voltmeter,which multiplies the test voltage before it is appliedto the instrument (e.g., voltage-doubler probe).multiplier register In a computer, a register thatretains a number during a multiplication operation.multiplier resistor A resistor connected in serieswith a current meter (usually a milliammeter ormicroammeter) to make it a voltmeter. Also calledVOLTMETER MULTIPLER.multiplier tube See PHOTOMULTIPLIER TUBE.multipoint circuit A transmission circuit or system,in which information can be entered or retrievedat two or more locations.multipoint distribution service In radio broadcasting,the transmission of programs via microwavelinks from a central facility to variouslocal stations.multipolar Pertaining to the presence of more thantwo magnetic poles.multipolar machine A motor or generator havinga number of poles in its armature and field.multiposition relay A relay having more than twopositions of closure. See, for example, SELECTORRELAY.multiposition switch A switch having more thantwo contacting positions. See, for example, SE-LECTOR SWITCH and STEPPING SWITCH.multiprocessing 1. In a computer system, therunning of more than one program at once.2. The use of more than one microprocessorsimultaneously in a single computer. Also calledparallel processing. 3. See TIME SHARING.multiprogramming Also called multitasking. In acomputer system, a technique that allows two ormore programs to be executed at the same time.