Page 41 - Electrical Engineering Dictionary

lation trapping. Adiabatic passage is often ple, for a network described by the nodal ad-
used for selective transfer of population be- mittance matrix, its adjoint network is repre-
tween two long-lived states of a multistate sented by the transposed admittance matrix
system, especially in cases where the two- of the original network. The adjoint network
step process of absorption followed by spon- is a basic tool in the computer-aided sensi-
taneous decay (optical pumping) would tend tivity analysis of electronic and microwave
to populate many other states. circuits.

adjacency graph a graph in which each adjustable-speed drive See variable
node represents an object, component, or fea- speed DC drive, variable speed AC drive.
ture in an image. An edge between two nodes
−
indicates two components that are touching admissible matrix a matrix M that can
or connected in the image. be obtained by fixing the free parameters of
the matrix M at some particular values. M −
adjacentchannelinterference(ACI) the is said to be admissible with respect to M.
interference caused by an adjacent frequency
band, e.g., in a system with frequency divi- admittance the reciprocal of the
sion duplex (FDD). Classified as either in- impedance of an electric circuit.
band or out-of-band adjacent channel inter-
admittance inverter an idealized de-
ference (ACI). The in-band ACI occurs when
vice or set of matrix parameters that func-
thecenterfrequencyofinterfering signalfalls
tions electrically like a quarter-wave lossless
within the band of the desired signal. The
transmission line of characteristic impedance
out-of-band ACI occurs when the center fre-
J at each frequency, thus transforming the
quency of interfering signal falls outside the
load admittance (Y LOAD )by +90 degrees and
bandwidth of the desired signal.
modifying the magnitude, resulting in an in-
put admittance (Y in ).
adjacent channel leakage power See
adjacent channel power. J 2
Y in =
Y load
adjacent channel power (ACP) a power
of distortion components generated in adja-
admittance matrix the inverse of the
cent channel, which is caused by a nonlinear-
impedance matrix in the method of moments.
ity of high-power amplifier amplifying a dig-
itally modulated signal such as QPSK, QAM,
ADP Seeammoniumdihydrogenphosphate.
etc. Adjacent channel power is defined as a
ratio of signal power in channel and leakage
power in adjacent channel. ADPCM See adaptive differential pulse
code modulation.
adjacent channel reuse ratio (ACRR)
the reuse ratio between radio communication ADSL See asymmetric digital subscriber
cells using adjacent radio channels. See also line.
reuse ratio.
adsorbent the material of an adsorber,
adjacent channels radio channels occu- for example, silica gel, alumina, and char-
pying radio frequency allocations n and n±1. coal. Adsorbent materials are characterized
by high surface to volume ratio.
adjoint network a network with an iden-
tical structure to the original one, but with adsorber (1) condensation of a gas on the
possibly different elements. As an exam- solid material.

c
2000 by CRC Press LLC