Page 209 - Electrical Engineering Dictionary

destructiveread readingprocessinwhich developed torque the torque created by
the information is lost from memory after be- an electric motor including torque required
ing read out. to overcome the friction and windage losses
of the motor. This value will be higher than
detectability thepropertyofasystemcon- the shaft torque, which is actually delivered
cerning the existence of a stabilizing output to the load.
injection. For linear time-invariant systems,
it is characterized by the observability (see development the process by which a liq-
the definition) of the unstable modes. uid, called the developer, selectively dis-
solves a resist as a function of the exposure
detective quantum efficiency (DQE) of energy that the resist has received.
a photodetector, the ratio of its quantum ef-
ficiency (Q e ) to its power noise factor (k), deviation a measure of the dispersion
i.e., DQE = 3DQ e /k. This is a general among the elements in a set of data. Some-
relationship that applies to electrical, photo- times, a deviation is defined as failure to meet
graphic, and biological (e.g., the eye) types the specified critical limits.
of photodetectors.
deviation ratio the allowable frequency
detector (1) a device that converts RF in- deviation for an FM signal divided by the
put signals to a corresponding DC output sig- highest modulating frequency.
nal.
(2) in optics, a circuit, usually containing device a hardware entity that exists out-
a diode that converts the intensity of light into side of the motherboard, and is accessed
an electrical signal. Used in a variety of ap- through device drivers. Devices often relate
plications including power sensing, leveling, to I/O (floppy drives, keyboards, etc.).
and modulation envelope reproduction. See
also photodetector. device controller (1) a device used to con-
nect a peripheral device to the main com-
deterministic control of uncertain systems puter; sometimes called a peripheral con-
an approach to the control of uncertain sys- troller.
tems that is effective over a specified range (2) software subroutine used to communi-
of the system parameter variations. These cate with an I/O device.
methods do not require on-line identification
of the values of the system parameters to device driver program that controls an in-
yield the desired robust performance. No sta- put/output device, usually providing a stan-
tistical information about uncertain parame- dard form of interface to the programs that
ters is required. The two main approaches utilize the device. Device drivers perform
are variable structure sliding mode control the basic functions of device operation.
and Lyapunov theory approach.
device register register in an I/O device
deuteron the nucleus of the deuterium that may be read or written by the processor
atom (an isotope of the hydrogen) consisting to determine status, effect control, or transfer
of a proton and a neutron. data.

developed power the power converted device scaling to increase device speed
from electrical to mechanical form in an elec- and circuit density as well as reduce power
tric motor. The developed power of a motor consumption, all three dimensions of transis-
can be calculated from the developed torque tors are reduced and the impurity concentra-
and motor speed. tions increased by interrelated scale factors.

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2000 by CRC Press LLC