Page 36 - Electrical Engineering Dictionary

active power line conditioner a device ACTV See advanced compatible tele-
which senses disturbances on a power line vision.
andinjectscompensatingvoltagesorcurrents
to restore the line’s proper waveform. acuity sharpness. The ability of the eye
to discern between two small objects closely
active RC filter an electronic circuit spaced, as on a display.
made up of resistors, capacitors, and opera-
tional amplifiers that provide well-controlled adaptability the capability of a system to
linear frequency-dependent functions, e.g., changetosuittheprevailingconditions, espe-
low-, high-, and bandpass filters. cially by automatic adjustment of parameters
through some initialization procedure or by
training.
active redundancy a circuit redundancy
technique that assures fault-tolerance by de-
adaptation layer control layer of a mul-
tecting the existence of faults and performing
tilayer controller, situated above the direct
some action to remove the faulty hardware,
control layer and — usually — also above the
e.g., by standby sparing.
optimizing control layer, required to intro-
duce changes into the decision mechanisms
active region semiconductor material
of the layer (or layers) below this adaptation
doped such that electrons and/or holes are
layer; for example adaptation layer of the in-
free to move when the material is biased. In
dustrial controller may be responsible for ad-
the final fabricated device, the active regions
justing the model used by the optimizing con-
are usually confined to very small portions of
trol and the decision rules used by the direct
the wafer material.
(regulation) control mechanisms.
active-high (1) a logic signal having its adapter a typical term from personal
asserted state as the logic ONE state. computers. A circuit board containing the
(2) a logic signal having the logic ONE interface toward an additional peripheral de-
state as the higher voltage of the two states. vice. For example, a graphic adapter (inter-
face boards like EGA, VGA, CGA), a game
controller, a SCSI controller, a PCMCI inter-
active-low (1) a logic signal having its
face, etc.
asserted state as the logic ZERO state.
(2) a logic signal having its logic ONE
adaptive algorithm (1) a method for ad-
state as the lower voltage of the two states;
justing the parameters of a filter to satisfy an
inverted logic.
objective (e.g., minimize a cost function).
(2) an algorithm whose properties are ad-
actuator (1) a transducer that converts justed continuously during execution with
electrical, hydraulic, or pneumatic energy to the objective of optimizing some criterion.
effective motion. For example in robots, ac-
tuators set the manipulator in motion through adaptive antenna antenna, or array of
actuation of the joints. Industrial robots antennas, whose performance characteristics
are equipped with motors that are typically can be adapted by some means; e.g., the
electric, hydraulic, or pneumatic. See also pattern of an array can be changed when
industrial robot. the phasing of each of the array elements is
(2) in computers, a device, usually me- changed.
chanical in nature, that is controlled by a
computer, e.g., a printer paper mechanism or adaptive array an array that adapts itself
a disk drive head positioning mechanism. to maximize the reception of a desired sig-

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2000 by CRC Press LLC