NAND - A logic function of A and B that is true if either A or B is false
.
NAND CIRCUIT - A combination of a NOT function and an AND function in a
binary circuit that has two or more inputs and one output. The output is logic 0 only if
ALL inputs are logic 1; it is logic 1 if ANY input is logic 0 .
NATIONAL BUREAU OF STANDARDS (NBS) - A bureau of the United States
government that is responsible for maintaining the nation's electrical and physical
standards. The accuracy of all calibrated test equipment is traceable to NBS through the
Navy's METCAL program.
NATURAL FREQUENCY - See RESONANT FREQUENCY .
NATURAL HORIZON - The line-of-sight horizon .
NAUTICAL MILE - The length of a minute of arc of a great circle of the
earth (6,076 ft) .
NAUTICAL RADAR MILE - See RADAR MILE .
NEAR SYNCHRONOUS ORBIT - An orbit in which the satellite rotates close to
but not exactly at the same speed as the earth .
NEGATION - The process of inverting the value of a function or variable .
NEGATIVE ALTERNATION - That part of a sine wave that is below the
reference level .
NEGATIVE CLAMPER - A circuit that clamps the upper extremity of the output
waveshape to a dc potential of 0 volts .
NEGATIVE ELECTRODE - A terminal or electrode having more electrons than
normal. Electrons flow out of the negative terminal of a voltage source .
NEGATIVE FEEDBACK - Feedback in which the feedback signal is out of phase
with the input signal. Also called DEGENERATIVE FEEDBACK .
NEGATIVE LOGIC - The form of logic in which the more positive voltage
level represents a logic 0, FALSE, or LOW and the more negative voltage represents a logic
1, TRUE, or HIGH .
NEGATIVE-RESISTANCE ELEMENT - A component having an operating region in
which an increase in the applied voltage increases the resistance and produces a
proportional decrease in current. Examples include tunnel diodes and silicon unijunction
transistors .
NEGATIVE TEMPERATURE COEFFICIENT - A characteristic of a semiconductor
material, such as silver sulfide, in which resistance to electrical current flow decreases
as temperature increases .
NETWORK - A combination of electrical components. In a parallel circuit it
is composed of two or more branches .
NEUTRAL - (1) In a normal condition, hence neither positive nor negative.
A neutral object has a normal number of electrons (the same number as protons) . (2) The
teletypewriter operation where current flow represents a mark and no flow represents a
space .
NEUTRALIZATION - The process of counteracting or "neutralizing"
the effects of interelectrode capacitance .
NEWTON'S SECOND LAW OF MOTION - If an unbalanced outside force acts on a
body, the resulting acceleration is directly proportional to the magnitude of the force,
is in the direction of the force, and is inversely proportional to the mass of the body .
NODE - The fixed minimum points of voltage or current on a standing wave
or antenna .
NOISE - (1) In reference to sound, an unwanted disturbance caused by
spurious waves that originate from man-made or natural sources . (2) In radar, erratic or
random deflection or intensity of the indicator sweep that tends to mask small echo
signals .
NOISE FIGURE - The ratio of output noise to input noise in a receiver .
NOISE LIMITER - Circuit that clips the peaks of the noise spikes in a
receiver .
NOISE SILENCER - See NOISE LIMITER .
NOISE SUPPRESSOR - See NOISE LIMITER .
NO-LOAD CONDITION - The condition that exists when an electrical source or
secondary of a transformer is operated without an electrical load .
NONDEGENERATIVE PARAMETRIC AMPLIFIER - A parametric amplifier that uses a
pump signal frequency that is higher than twice the frequency of the input signal .
NONDIRECTIONAL - See OMNIDIRECTIONAL .
NONLINEAR DEVICE - A device in which the output does not rise and fall in
direct proportion to the input .
NONLINEAR IMPEDANCE - An impedance in which the resulting current through
the device is not proportional to the applied voltage .
NONLUMINOUS BODIES - Objects that either reflect or diffuse light that
falls upon them .
NONRESONANT LINE - A transmission fine that has no standing waves of
current or voltage .
NONTRIP-FREE CIRCUIT BREAKER - A circuit breaker that can be held in the
ON position during an overcurrent condition .
NOR - A logic function of A and B that is true if both A and B are false .
NOR GATE - An OR gate that is followed by an inverter to form a binary
circuit in which the output is a logic 0 if ANY of the inputs is a logic 1 and the output
is a logic 1 only if ALL the inputs are a logic 0 .
NORMAL - The imaginary line perpendicular to the point at which the
incident wave strikes the reflecting surface. Also called the perpendicular .
NOT CIRCUIT - A binary circuit with a single output that is always the
opposite of the input. Also called an INVERTER CIRCUIT .
NPN - AN NPN transistor is formed by introducing a thin region of P-type
material between two regions of N-type material .
NULL - On a polar-coordinate graph, the area that represents minimum or 0
radiation .
NUMBER - (1) A mathematical entity that may indicate quantity or amount of
units. (2) Loosely, a numeral. An abstract mathematical symbol for expressing a quantity.
In this sense, the manner of representing the number is immaterial. Take 26, for example;
this is its decimal form - but it could be expressed as a binary (base 2), octal (base 8),
or hexadecimal (base 16) number .
NUMBER REPRESENTATION - The representation of numbers by agreed sets of
symbols according to agreed rules .
NUMBER SYSTEM - Loosely, a number representation system. Any system for
the representation of numbers (see POSITIONAL NOTATION) .
NUMERAL - (1) A discrete representation of a number. For example, twelve,
12, XII, 11002 are four different numerals that represent the same number. (2) A numeric
word that represents a number .
NUTATING - Moving an antenna feed point in a conical pattern so that the
polarization of the beam does not change .
