Page 85 - Electrical Engineering Dictionary

changes around the accelerator. There are sities, E and H, via dyadic constitutive pa-
separate beta functions for the x and y planes. rameters. The permittivity, permeability, and
The square root of bx is proportional to the magnetoelectric coupling parameters are ten-
beam’s x-axis extent in phase space. sor quantities.
(2) media for which the electric and mag-
beta particle an electron or positron emit- netic fields displacements, D and B respec-
ted from a radioactive source. tively, are related to the electric and magnetic
field strength E and H by general dyadics.
betatron oscillation stable oscillations
about the equilibrium orbit in the horizontal bi-isotropic media media for which the
and vertical planes. First studied in betatron electric and magnetic fields displacements, D
oscillators, betatron oscillation is the trans- andB, respectively, arescalarlydependentby
verse oscillation of particles in a circular ac- both the electric and magnetic field strength
celerator about the equilibrium orbit. The E and H. For these media the constitutive
restoring force for the oscillation is provided relations are
by focusing components in the magnetic field √
D = E + (χ − jκ) µ 0 0 H
that act to bend a particle that is off the equi-
√
librium orbit back toward it. B = H + (χ + jκ) µ 0 0 E
where is the permittivity, µ the permeabil-
Beverage antenna simple traveling wave
ity, and the subscript 0 refers to free-space.
antennaconsistingofanelectricallylonghor-
Bi-isotropic media can be reciprocal (χ = 0)
izontal wire above ground with a termination
or nonreciprocal (χ 6= 0); nonchiral (κ = 0)
resistance between the end of the wire and
or chiral (κ 6= 0).
ground equal to the characteristic impedance
of the wire/ground transmission line.
bi-stable pertaining to a device with two
stable states, e.g., bi-stable multivibrator; cir-
Bezout identity of 2-D polynomial matri-
cuit that has two possible output states and
ces a systems identity defined as follows:
that will remain in its current state without
let N R (z 1 ,z 2 ), D R (z 1 ,z 2 )(N L (z 1 ,z 2 ),
D L (z 1 ,z 2 )) be two right (left) coprime poly- requiring external inputs; a flip-flop.
nomial matrices, then there exists a polyno-
bi-stable device See flip-flop.
mial matrix in z 2 , say E R (z 2 ), (E L (z 2 )) and
two polynomial matrices X R (z 1 ,z 2 ),
bias the systematic (as opposed to ran-
Y R (z 1 ,z 2 )(X L (z 1 ,z 2 ), Y L (z 1 ,z 2 )) such that
dom) error of an estimator.
X R (z 1 ,z 2 ) D R (z 1 ,z 2 )
bias current the arithmetic average of
+ Y R (z 1 ,z 2 ) N R (z 1 ,z 2 ) = E R (z 2 )
the currents that flow in the input leads of an
(N L (z 1 ,z 2 ) Y L (z 1 ,z 2 ) op-amp.
+ D L (z 1 ,z 2 ) X L (z 1 ,z 2 ) = E L (z 2 ))
bias lighting technique used in video
tubes to correct for undesirable artifacts such
BGA See ball grid array. as lag. Applying a uniform light source to
the surface of the tube (the photoconductive
BI See bandwidth improvement. layer) will create a bias current in the tube,
thereby minimizing the undesirable charac-
bi-anisotropic media (1) a class of ma- teristics.
terial in which the electric and magnetic flux
densities, D and B, are each linearly related bias network a key aspect of microwave
to both the electric and magnetic field inten- circuit design is to apply the proper DC bias

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