Page 255 - Electrical Engineering Dictionary

(2) a device, consisting of a micropro- may need to emit some pollutant. The resale
cessor, firmware (often in EPROM), and/or value of the pollution credit forms a finan-
FPGAs/EPLDs, which is dedicated to spe- cial incentive for a facility to emit as little
cific functions, and becomes an inseparable pollution as possible.
component of a device or system, in contrast
to devices that are controlled by stand-alone emissivity the fraction of the power in-
computers. Embedded computers use em- cident on a material that is reradiated after
bedded software, which integrates an oper- being absorbed by the material. For a mate-
ating system with specific drivers and ap- rial in thermal equilibrium, the emissivity is
plication software. Their design often re- equal to the absorptivity.
quires special software–hardware codesign
methods for speed, low power, low cost, high emitter follower See common collector
testability or other special requirements. amplifier.
(3) software that is part of a larger system
and performs some of the requirements of emitter-coupled logic (ECL) a very high
that system; e.g., software used in an aircraft speed bipolar transistor logic circuit family.
or rapid transit system. Such software does
not provide an interface with the user. See
emitter-coupled pair See differential
firmware.
pair.
embedded computer system See embed-
EMP See electromagnetic pulse.
ded computer, embedded system.
empirical distribution function See
embedded passives 3-D packaging so-
histogram.
lution, consisting of embedding passive el-
ements into the mounting substrate, for in-
empirical model mathematical model
creasing the packaging efficiency.
based on curve-fitting specific mathematical
functions to measured data, rather than on
embedded system software that is part
device physics. Empirical models generally
of a larger system and performs some of the
have a low to midrange modeling valuation
requirements of that system; e.g., software
coefficient.
used in an aircraft or rapid transit system.
Such software does not provide an interface
with the user. See also firmware. EMTP the Electro-Magnetic Transient
Program, a computer program which simu-
EMC See electromagnetic compatibility. lates an electric power system such that its
response to disturbances may be accurately
EMI See electromagnetic interference. predicted.

EMI filter See electromagnetic interfer- emulate executing a program compiled to
ence filter. one instruction set on a microprocessor that
usesanincompatibleinstructionset, bytrans-
emission credit a scheme in the USA for lating the incompatible instructions while the
the control of nitrous oxide and sulfur diox- program is running.
ideemissionsfromindustrialplants. Autility
can purchase from the government the right emulation a model that accepts the same
to emit a certain quantity of pollutant. If it inputs and produces the same outputs as a
does not emit this amount, the credit can be given system. To imitate one system with
sold on the market to another plant which another. Contrast with simulation.

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2000 by CRC Press LLC