Page 33 - Electrical Engineering Dictionary

acknowledge (1) a signal which indicates another signal in a second cell, or with fixed
that some operation, such as a data transfer, signals on a mask.
has successfully been completed.
(2) to detect the successful completion of acousto-optic deflector device device
an operation and produce a signal indicating where acousto-optic interaction deflects the
the success. incident beam linearly as a function of the
input frequency of the RF signal driving the
acoustic attenuation the degree of am- device.
plitude suppression suffered by the acous-
tic wave traveling along the acousto-optic acousto-optic device descriptor of
medium. acousto-optic cells of any design; generally
describes a cell plus its transducer struc-
acoustic laser a laser (or maser) in which ture(s), and may encompass either bulk,
the amplified field consists of soundwaves or guided-wave, or fiber-optic devices.
phonons rather than electromagnetic waves;
phonon laser or phaser.
acousto-optic effect the interaction of
light with sound waves and in particular the
acoustic memory a form of circulating
modification of the properties of a light wave
memory in which information is encoded in
by its interactions with an electrically con-
acoustic waves, typically propagated through trollable sound wave. See also Brillouin
a trough of mercury. Now obsolete. scattering.
acoustic velocity the velocity of the
acousto-optic frequency excisor similar
acoustic signal traveling along the acousto-
to an acousto-optic spectrum analyzer where
optic medium.
the RF temporal spectrum is spatially and se-
lectively blocked to filter the RF signal feed-
acoustic wave a propagating periodic
ing the Bragg cell.
pressure wave with amplitude representing
either longitudinal or shear particle displace-
acousto-optic instantaneous spectrum an-
ment within the wave medium; shear waves
alyzerinBraggmode deviceinwhichthe
are prohibited in gaseous and liquid media.
temporal spectrum of a radio frequency sig-
nal is instantaneously and spatially resolved
acousto-optic cell a device consisting of
in the optical domain using a Fourier trans-
a photo-elastic medium in which a propa-
form lens and a RF signal-fed Bragg cell.
gating acoustic wave causes refractive-index
changes, proportional to acoustic wave am-
plitude, that act as a phase grating for diffrac- acousto-optic modulator a device that
modifies the amplitude or phase of a light
tion of light. See also Bragg cell.
wave by means of the acousto-optic effect.
acousto-optic channelized radiometer
See acousto-optic instantaneous spectrum acousto-optic processor an optical sys-
analyzer in Bragg mode. tem that incorporates acousto-optic cells con-
figured to perform any of a number of math-
acousto-optic correlator an optical sys- ematical functions such as Fourier trans-
tem that consists of at least one acousto- form, ambiguity transforms, and other time-
optic cell, imaging optics between cells and frequency transforms.
fixed masks, and photodetectors whose out-
puts correspond to the correlation function of acousto-optic scanner a device that uses
the acoustic wave signal within one cell with an acoustic wave in a photoelastic medium

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2000 by CRC Press LLC