Page 315 - Electrical Engineering Dictionary

medium is a gallium-arsenide semiconductor
alloy.
G GaAs/AlGaAs most commonly grown

semiconductor epitaxial heterostructure due
to its lattice match, common anion, and ex-
isting technology base of GaAs devices.
G (giga) a prefix indicating a quantity of
9
10 . For instance, a gigabyte (GB) of storage
is 1,000,000,000 (typically implemented as Gabor transform a short-time Fourier
3
2 0) bytes. transform in which the window function is
the Gaussian function.
common notation for compression.
G CR
See compression. gain (1) the ratio of the output variable of
a device to its input variable. For calculation
g d common notation for DC drain con- purposes, the dimensionality of the gain is
ductance. simply the unit of the output variable divided
by the unit of the input variable. The gain of
G I common notation for current gain. G I a device is a dimensionless value only when
is dimensionless. the electrical units of both the input and out-
put variables are the same (e.g., voltage gain,
g m common notation for DC transconduc- current gain, power gain, etc.). In this case,
tance. a gain greater than one indicates an increase
from input to output, while a value for gain
G P common notation for power gain in less than one is indicative of a decrease (or
decibels. attenuation). The overall gain of several cas-
caded components is found by multiplying
G T common notation for transducer gain the individual gains of each component in the
in amperes/volt. system. Gain is often expressed in decibels
to facilitate calculation of cascaded gains in
G V common notation for voltage gain. a system. See also decibel.
G V is dimensionless.
(2) the ratio of the radiation intensity of
a particular antenna to that of an isotropic
G-line a line of the mercury spectrum cor-
radiator, in the same direction and at the same
responding to a wavelength of about 436 nm.
distance.
GaAlSb/InGaAlAsSb nearly lattice
matched semiconductor heterostructure sys- gain circles circles of constant gain plot-
tem capable of “staggered” band lineups in ted on the Smith chart that can be used to
which the electrons and holes congregate in graphically impedance match a device to
separate layers. Unique transport proper- achieve a desired gain. The circles are gener-
ties are utilized in optical devices and tunnel ated by plotting on the Smith chart the solu-
structures. tion for the source reflection coefficient, 0 s ,
or load reflection coefficient, 0 L , in the trans-
GaAs periodic table symbol for gallium ducer gain equation for a fixed value of
arsenide. See gallium arsenide.
G =
GaAs laser a semiconductor laser for 2 2 2
|S 21 | 1−|0 S | 1−|0 L |
wavelengths in the near infrared. The active 2
|(1−S 11 0 S )(1−S 22 0 L )−S 12 S 21 0 L 0 S |

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