Page 165 - Electrical Engineering Dictionary

constant modulus algorithm (CMA) ture voltage. For AC induction motors, this
one of a number of algorithms (i.e., maxi- region is below rated speed and is achieved
mum ratio combining, Bartlett, Capon, and by reducing the frequency of the applied volt-
LMS) proposed in the literature for the adap- age.
tation of the weights associated with each ra-
diating element and for combining signals re-
constitutive relation describes the rela-
ceived on radiating elements.
tionbetweenthe intensityvectors andtheflux
density vectors in a medium.
constant-current transformer two-coil
transformer with a moveable secondary coil
constitutive relationships a set of equa-
used to provide constant output current to
tionsthatcoupletheelectric-fieldintensityE,
a variable load. Constant current is main-
magnetic-field intensity H, the electric flux
tained by mounting both the primary and sec-
ondary coils on the center element of a shell- density D, and the magnetic flux density B to
type core and allowing the secondary coil to one another. For simple media, the constitu-
move up and down with changes in demand tive relationships are D = E, and B = µH,
for load current. Increasing current demand where and µ are the scalar permittivity and
due to a reduction in load impedance causes permeability of the medium, respectively.
the secondary coil to move away from the
primary coil. Increasing the coil separation constraining core an internal support-
increases flux leakage and reduces the sec- ing plane in a packaging and interconnecting
ondary output voltage. The reduced output structure, used to alter the structure’s coeffi-
voltage counteracts the demand for more cur- cient of thermal expansion.
rent. Increases in load impedance reverse the
process. Movement of the secondary coil is
constraint length in convolutional codes,
controlledautomaticallybyattachingthesec-
an indication of the number of source words
ondary coil to a counterweight and pulley as-
that affect the value of each coded word. Two
sembly and orienting the coil windings such
typical forms are:
that their flux directions oppose. Increases
in secondary current increase the magnetic 1. A code with constraint length K,in
repulsion between the coils, which, aided by which the value of each coded word is af-
the counterweight, moves the secondary coil fected by the present source word and up to
away from the primary. Reductions in sec- K − 1 previous source words.
ondary current produce the opposite effect.
2. The number of shifts over which a sin-
gle message bit can influence the output of a
constant-horse power drive a variable
convolutional encoder.
speed drive that is operating in a speed region
where it is capable of delivering rated power.
constraint propagation artificial intelli-
For DC machines, this region is above base
gence technique in which a hypothesis gener-
speed and is achieved by field weakening.
ates constraints that reduce the search space
For AC induction motors, this region is above
overtherestofthedata. Ifnoeventualcontra-
rated speed and is achieved by increasing the
diction is derived, then a “match” is achieved.
frequency of the applied voltage.
constant-torque drive a variable-speed constructive algorithm learning algo-
drive that is operating in a speed region where rithm that commences with a small network
it is capable of maintaining rated torque. For and adds neural units as learning proceeds
DC machines, this region is below base speed until the problem of interest is satisfactorily
and is achieved by reducing the applied arma- accommodated.

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2000 by CRC Press LLC