18WuD2x

noise reduction • nominal value 479
noise reduction See NOISE SUPPRESSION.
noise residue The residual output (see NULL
VOLTAGE, 1) of a balanced bridge, caused entirely
by noise.
noise silencer A noise-limiting circuit that removes
noise-pulse transients with little or no effect
on the signal from which the noise is
removed. Compare NOISE CLIPPER.
noise source See NOISE GENERATOR.
noise spike See NOISE PULSE.
noise suppression 1. In communications, the reduction
of noise amplitude to a level that is noncompetitive
with desired signals. 2. In audio
recording and reproduction, reduction of unwanted
noise (e.g., hiss) to the greatest extent
possible without degrading the fidelity of the desired
audio. Compare NOISE ELIMINATION.
noise suppressor A device for eliminating electrical
noise or reducing its amplitude. See, for example,
AUTOMATIC NOISE LIMITER and NOISE
BLANKER.
noise temperature At a given frequency, the temperature
of a passive system that has the same
noise power per unit bandwidth as that observed
at the terminals of a device under test.
noise voltage The voltage component of an electrical
noise signal.
noise-voltage generator A signal generator that
supplies an alternating-current waveform containing
random-frequency pulses of relatively
uniform distribution over a given frequency spectrum.
Compare NOISE-CURRENT GENERATOR.
noisy mode During normalization of a floatingpoint
number, the generation of digits, excluding
zero, as part of the fixed-point part (see NOR-
MALIZE).
NOL 1. Abbreviation of National Ordnance Laboratory.
2. Abbreviation of Naval Ordnance Laboratory.
no-load current 1. Output-electrode current (e.g.,
drain, plate, or collector current) when a device is
not delivering output to an external load. 2. Current
flowing in the primary winding of an unloaded
transformer.
no-load losses Losses in an unloaded transformer
(see NO-LOAD CURRENT, 2).
no-load speed The rotational speed of an unloaded
motor.
no-load voltage The open-circuit output voltage of
a power supply, amplifier, generator, or network.
nominal 1. Named, rated, or specified. The nominal
value of a speaker, for example, might be 8 ohms,
even though the actual impedance value depends
on the frequency of the applied signal. 2. Approximate,
and specified as a typical example only, for
the purpose of identifying the operating or value
range. For example, an automotive circuit might
have a nominal rating of 12 volts—even though it
can be operated at 10 volts to 14.6 volts.
nominal band In a facsimile signal, the waveband
extending between zero and the maximum frequency
of modulation.
nominal bandwidth 1. For a filter, the difference
f c2 f c1 , where f c1 is the nominal lower cutoff frequency
and f c2 is the nominal upper cutoff frequency.
2. For an allocated communication
channel, the total bandwidth, including upper
and lower guard frequencies. 3. The intended and
specified bandwidth of a given channel, regardless
of the bandwidth of the signal on that frequency
at any given time.
Amplitude
Channel
X
Nominal
bandwidth
Channel
Y
Nominal
bandwidth
nominal bandwidth, 2
Freq.
nominal capacitance The rated (“label”) value of a
capacitor. Also see NOMINAL VALUE.
nominal current The rated (“nameplate”) value of
required current or of current output. Also see
NOMINAL VALUE.
nominal horsepower The rated (“nameplate”)
horsepower of a machine, such as a motor. Also
see NOMINAL VALUE.
nominal impedance The rated impedance of a circuit
or device. Also see NOMINAL VALUE.
nominal inductance The rated (“label”) value of a
coil’s inductance. Also see NOMINAL VALUE.
nominal line pitch In a television raster, the average
center-to-center separation between adjacent
lines.
nominal line width 1. For a television raster, the
factor 1/n, where n is the number of lines per
unit width for the direction in which the lines
progress. 2. In facsimile, the average center-tocenter
separation of scanning or recording lines.
nominal power factor The rated (“nameplate”)
value of power factor of a device. Also see NOMI-
NAL VALUE.
nominal power rating The rated (“nameplate”)
value of power output, power drain, or power dissipation.
Also see NOMINAL VALUE.
nominal Q The rated (“nameplate”) value of Q of a
capacitor, inductor, transformer winding, or tank
circuit. Also see NOMINAL VALUE.
nominal rating See NOMINAL, 1, 2.
nominal resistance The rated (“label”) value of a resistor
or similar device. Also see NOMINAL VALUE.
nominal speed The highest speed of a dataprocessing
unit or system, disregarding slowdowns
because of factors other than computational operations.
nominal value A named, specified, rated, or labeled
value, given without reference to tolerance.