Page 332 - Electrical Engineering Dictionary

tiple access interference generated by this cost control techniques are usually applied to
group of users is estimated, and then sub- nominally linear systems and quadratic cost
tracted from the received signal. This de- functionals.
tection and cancellation is continued succes-
sivelyuntilallusersinallgroupsaredetected. guard band a design technique for a color
CRT intended to improve the purity perfor-
group velocity (1) a quantity proved to mance of the device by making the lighted
indicate (in most dispersive media) the speed area of the screen smaller than the theoretical
of energy propagation of wavepackets. tangency condition of the device geometry.
(2) in an optical fiber, the speed at which a
signalsuperimposedonanopticalwaveprop- guard digits those extra digits of the sig-
agates. nificand in a floating-point operand that must
be retained in order to allow correct normal-
Groupe Special Mobile (GSM) a digital ization and rounding of the result’s signifi-
cellular communications network standard cand.
developed in Europe in the 1980s and now
implemented in many countries throughout guarded machine classification describ-
the world. The acronym originally denoted ing an electrical machine constructed with an
Groupe Special Mobile, after the French- open frame in which rotating components or
based group that developed the system. Now live electrical parts are guarded by screens.
the acronym denotes Global System for Mo- Screen openings are restricted so that a rod
bile. GSM is one of a group of systems that with a diameter of 0.75 inches cannot contact
are usually referred to as second-generation any part within 4 inches of the guarded open-
cellular systems. The system uses 200 kHz ing, and a rod with a diameter of 0.5 inches
channels, GMSK modulation and frequency cannot contact any part more than 4 inches
hopping. GSM transmits digitally encoded inside the guarded opening.
speech at a rate of approximately 13 kbps
and makes extensive use of channel error- guidewavelength thedistanceoverwhich
correcting codes. the fields of propagating modes repeat them-
selves in a waveguide.
GSG See ground-signal-ground.
guided scrambling an extension of the
GSM See Global System for Mobile Com- self-synchronizing scrambling line code pro-
munications. cedure in which the source bit stream is aug-
mented with appropriately valued bits prior
GSVQ gain-shape vector quantization. to scrambling in order to ensure that the
See shape-gain vector quantization. scrambled sequence contains good line code
properties.
GTAW See gas tungsten arc welding.
guided wave interconnect a means for
GTO See gate turnoff thyristor. connecting electrical systems such as com-
puters and computer circuit boards optically,
guaranteed cost control a methodology using optical fibers and optical circuits of
of robust controller design whose objective channel waveguides.
is to ensure that the value of the performance
index for the real system represented by the guy a wire which extends at an angle from
family of models with uncertainty chang- a utility pole to the ground in order to brace
ing within a given set is guaranteed to be the pole against toppling due to unbalanced
not greater than a given value. Guaranteed forces from the utility lines it supports.

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2000 by CRC Press LLC