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 NATIONAL ELECTRICAL CODE (NEC). A standard (NFPA-70) governing the use of
electrical wire, cable, and fixtures installed in buildings. It is sponsored
by the Natioanl Fire Protection Association (NFPA) under the auspices of the
American National Standards Institute (ANSI).
NEAR FIELD. The region of the field immediately surrounding an antenna where
the inductive and capacitive fields predominate. In this region the angular
distribution of the field varies with the distance from the antenna.
NEUTRAL. The AC power system conductor which is intentionally grounded on the
supply side of the service disconnecting means. It is low potential (white)
side of a single phase AC circuit or low potential fourth wire of a
three-phase WYE distribution system. The neutral conductor provides a current
return path for AC power currents whereas the ground (or green) conductor
should not provide a current return path except during fault conditions.
PENETRATION. The passage through a partition or wall of an equipment or
enclosure by a wire, cable, or other conductive object.
PHYSICAL CONTROL ZONE (PCZ). The space surrounding equipment processing
classified information, which is under sufficient physical and technical
control to preclude a successful hostile intercept of any classified
information from within this space.
PLANE WAVE. An electromagnetic wave which predominates in the far field region
of an antenna, and with a wavefront which is essentially in a flat plane. In
free space, the characteristic impedance of a plane wave is 377 ohms.
RADIATION.
The emission and propagation of electromagnetic energy through
space.
RADIATION RESISTANCE. The resistance which, if inserted in place of an
antenna, would consume the same amount of power that is radiated by the
antenna.
RADIATION HAZARDS TO PERSONNEL (RADHAZ). Potential for personnel to be
adversely affected by electromagnetic radiation.
RADIATED EMISSION. Desired or undesirable electromagnetic energy which is
propagated through space. Such an emission is called "radiated interference"
if it is undesirable.
RADIATED SUSCEPTIBILITY. A measure of the radiated interference field
required to cause equipment degradation.
RADIO FREQUENCY INTERFERENCE (RFI).
Synonymous with electromagnetic
interference.
RED/BLACK CONCEPT. The concept that electrical and electronic circuits,
components, equipment, systems, and so forth, which handle classified plain
language information in electric signal form (RED) be separated from those
which handle encrypted or unclassified information (BLACK). Under this
concept, RED and BLACK terminology is used to clarify specific criteria
relating to, and to differentiate between such circuits, components,
equipment, systems, and so forth and the areas in which they are contained.
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