18WuD2x

ARSR • assemble 41
ARSR Abbreviation of air route surveillance radar.
articulation A measure of the effectiveness of voice
communications, expressed as the percentage of
speech units understood by the listener when the
effect of context is negligible.
artificial antenna See DUMMY ANTENNA.
artificial ear A microphone-type sensor, equivalent
to the human ear, used to measure sound
pressures.
artificial echo 1. In radar practice, the reflections
of a transmitted pulse returned by an artificial
target. 2. A signal from a pulsed radio-frequency
(RF) generator, delayed to simulate an echo.
artificial ground The effective ground provided by
the radials or disk of a ground-plane antenna, as
opposed to actual ground (the earth itself ). Compare
TRUE GROUND.
artificial horizon In aircraft instrumentation, a
device that displays lines showing the position of
the aircraft in flight, with reference to the horizon.
artificial intelligence Abbreviation, AI. 1. A specialized
field of computer science overlapping
with electronics, biology, physiology, and other
sciences, concerning attempts to develop advanced
computer systems that can emulate the
processes of the human mind. 2. The ability of a
computer to learn from its mistakes, refine its
own processes, and perhaps ultimately reason in
a humanlike manner.
artificial ionization An artificial reflecting layer
that is created in the atmosphere to provide a
skip condition.
artificial language A language that is not commonly
used, but has been devised for efficiency in
a particular situation—especially in a computer
system.
artificial life 1. The ultimate endpoint of ARTIFI-
CIAL INTELLIGENCE, wherein machines acquire
qualities, such as wisdom and the capability to
feel emotions. The state of the art is currently
nowhere near this point. 2. A hypothetical machine
or set of machines with lifelike qualities, including
human-level intelligence, wisdom, and
emotion.
artificial stimulus An electronic method of robot
guidance and navigation using radar, sonar, vision
systems, edge detection, and/or beacons.
artificial transmission line A network of capacitors
and inductors with characteristics similar to
those of the more bulky transmission line it replaces
in tests and measurements. It also serves
as a time-delay or phase-shift device and as a
pulse-forming network.
artificial voice A device used to test and calibrate
noise-canceling microphones, consisting essentially
of a small loudspeaker that has a baffle
whose acoustical properties simulate those of the
human head.
artos stripper A machine that cuts and strips wire
for the fabrication of multiconductor cables.
artwork 1. In the manufacture of printed circuits,
the scaled drawings from which the mask or etch
pattern is obtained photographically. 2. Collectively,
the illustrations depicting an electronic circuit,
device, or system.
As Symbol for ARSENIC.
ASA Abbreviation of AMERICAN STANDARDS AS-
SOCIATION.
asbestos A nonflammable fibrous material consisting
of calcium and magnesium silicates that is
used for high-temperature insulation.
A-scan A radar-screen presentation in which the
horizontal time axis displays distance or range,
and the vertical axis displays the amplitude of
signal pulse and echo pulses.
ascending node For a satellite orbiting the earth or
another planet, any point at which the groundtrack
crosses the equator as it moves from the
southern hemisphere into the northern hemisphere.
This node generally changes for each
succeeding orbit, because the earth or planet rotates
underneath the orbit of the satellite. Compare
DESCENDING NODE.
ascending pass For a specific point on the earth’s
surface, the time during which an artificial communications
satellite is accessible when its latitude
is moving northward. The duration of
accessibility depends on the altitude of the satellite,
and on how close its groundtrack comes to
the earth-based point. Compare DESCENDING
PASS.
ASCII Acronym (pronounced “ask-ee”) for American
Standard Code for Information Interchange.
ASI Abbreviation for American Standards Institute.
A-scope A radar system that displays an A-SCAN.
Askarel A synthetic, nonflammable liquid dielectric.
aspect ratio The width-to-height ratio of a video
image, generally three units high by four units
wide.
asperities On the surface of an electrode, tiny
points at which the electric field is intensified and
from which discharge is highly probable.
ASR 1. Abbreviation of AIRBORNE (or AIRPORT)
surveillance radar. 2. Abbreviation of AUTO-
MATIC SEND/ RECEIVE.
ASRA Acronym for automatic stereophonic recording
amplifier.
assemble 1. To gather subprograms into a complete
digital computer program. 2. To translate a