18WuD2x

interpreter • intrinsic conduction 377
a computer uses; if it is not resident in the computer’s
nonvolatile memory, it must be loaded
each time the machine is activated.
interrecord gap See INTERBLOCK SPACE.
interrupt A break in a computer program, as when
a background job is interrupted so that a foreground
job can be run. Also see BACKGROUND
JOB and FOREGROUND JOB.
interrupted commercial and amateur service
See INTERMITTENT COMMERCIAL AND AMA-
TEUR SERVICE.
interrupted continuous wave Abbreviation, ICW.
A continuous wave that is interrupted at regular
intervals, as in the chopping of a wave at a regular
rate. Compare CONTINUOUS WAVE (CW) and
MODULATED CONTINUOUS WAVE (MCW).
interrupted dc A direct current or voltage that is
periodically started and stopped by switching or
chopping.
interrupter contacts Auxiliary contacts operated
directly by the armature of a stepping switch.
interruption frequency See QUENCHING FRE-
QUENCY.
interruption-frequency oscillator See QUENCH
OSCILLATOR.
interrupt signal The signal that causes a break
(INTERRUPT) in a computer program.
intersatellite communication 1. Communication
between or among satellites. 2. Communication
between two earth-based stations, using
two or more satellites. 3. Communication between
an earth-based station and a satellitebased
station, using at least one intermediate
relaying satellite.
Satellites
Earth
intersatellite communication
intersecting storage ring A device for producing
great amounts of energy. It is similar to a vacuum
tube. High-speed subatomic particles are fed to a
ring-shaped evacuated structure in opposite directions.
The two particle beams collide at various
points, yielding high energy.
intersection The logical AND operation.
interstage capacitor A coupling capacitor used
between two circuit stages.
interstage coupling The transfer of a signal between
two circuit stages, such as those of an amplifier.
Common forms of interstage coupling
include direct coupling, capacitive coupling, transformer
coupling, diode coupling, and optoisolator
coupling.
interstage diode A semiconductor coupling diode
used between two circuit stages.
interstage transformer A coupling transformer
used between two circuit stages. It provides direct-current
isolation, and also can match purely
resistive impedances.
intersymbol interference In a digital communications
signal, a condition in which a given symbol
overlaps with one or more other symbols (either
immediately preceding it or immediately following
it), upsetting the ability of the receiver to decipher
signals in certain time intervals. The phenomenon
is sometimes a problem in time-division
multiplexing—especially at data speeds near the
maximum for the system.
intersystem A power-generating network of interconnected
separate systems.
intersystem communications Communications
between computer systems, either through direct
linking of central processors, or by mutual use of
peripherals and input/output channels.
intertie See INTERCONNECTION, 2.
interval 1. The amount of separation between successive
points, events, or quantities. 2. The continuous
range of values between two defined
points. 3. A specific period of time, with defined
beginning and ending points.
intervalometer A timing device for operating
equipment over a precisely defined time interval.
interval timer A device that provides power to an
equipment for a precise interval upon application
of a simple initiating signal or action. See also IN-
TERVALOMETER.
interword space The seven-unit interval between
words or code groups in telegraphy. Compare IN-
TERCHARACTER SPACE.
intoxication tester See DRUNKOMETER.
intracoding The coding of data using only data
that it contains.
Intrafax Western Union’s private facsimile system.
Intraframe A method of digital IMAGE COMPRES-
SION developed by MPEG (Moving Picture Experts
Group) and JPEG (Joint Photographic Experts
Group). It operates by eliminating redundant data
within image frames. Compare INTERFRAME.
intrinsic-barrier diode See PIN DIODE.
intrinsic-barrier transistor A bipolar transistor
with a layer of intrinsic semiconductor between
one of its pn junctions.
intrinsic concentration The number of minority
carriers exceeding the normal equilibrium number
in a semiconductor.
intrinsic conduction The flow of electron/hole
pairs in an intrinsic semiconductor subjected to
an electric field.