18WuD2x

306 function generator • fV
(e.g., sine, square, triangular, step-pulse) and frequencies
(or repetition rates). 2. An analog computer
circuit that produces a variable based on a
mathematical function and one or more input
variables.
function key 1. In digital communications, a keyboard
key used to control the form in which a
message will be received. 2. On a computer keyboard,
any of 12 keys (usually designated F1
through F12) that activates special functions.
The precise action of a given key depends on the
program being run.
function polling A polling technique in which a
disabled device signals its condition and specifies
the remedy.
function switch In a multifunction instrument,
such as a voltohm-milliammeter, the switch that
permits selection of the various functions.
function table 1. A table of mathematical function
values. 2. Hardware or software that translates
one representation of information into another.
3. A routine that allows a computer to use the
values of independent variables to determine the
value of a dependent variable.
fundamental Contraction of FUNDAMENTAL FRE-
QUENCY.
fundamental component The FUNDAMENTAL
FREQUENCY of a complex wave.
fundamental frequency 1. The lowest frequency
in a complex wave containing harmonic energy.
2. In a radio or television transmitter, the intended
frequency of operation. 3. In acoustics
and audio applications, the predominant pitch of
a musical tone.
fundamental group A set of trunk lines in a telephone
system, through which zone centers are
interconnected.
fundamental mode See DOMINANT MODE.
fundamental suppression Removal of the fundamental
frequency from a complex wave, leaving
only the harmonics, as in the operation of a null
network adjusted to the fundamental frequency.
fundamental units Base units of an absolute system
of units. Example: the meter (m), the kilogram
(kg), and the second (s) in the mks system.
fundamental wavelength The wavelength that
corresponds to the FUNDAMENTAL FREQUENCY
of a wave or signal.
fuse A safety device consisting of a wire of lowmelting-point
metal. When current passing
through the wire exceeds a prescribed (safe) level,
the resulting heat melts the wire and opens the
circuit, protecting equipment from damage. See
PROXIMITY FUSE.
fuse box A set of electrical fuses, usually enclosed
in a metal box.
fused junction In a semiconductor, a junction produced
by alloying metals to the semiconductor
material.
fused junction See ALLOY JUNCTION.
fuse resistor See FUSIBLE RESISTOR.
fuse wire The low-melting-point wire used in
fuses. See FUSE.
fusible resistor A low-value resistor that also
serves as a fuse in certain appliances, such as
television receivers.
fusing current The specified current level at which
a wire of a given diameter and material composition
will melt.
fusion 1. In acoustics, pertaining to delayed or
reflected waves that arrive within approximately
1
⁄25 of a second of the direct wave. So called because
the human ear/brain “fuses” (blends)
sounds together when they are separated by
less than about 1 ⁄25 second. If the delay is longer,
the ear/brain usually perceives an echo instead.
2. In a nuclear reaction, the uniting of
two atomic nuclei, accompanied by the release
of energy.
future labels In a computer system, program instruction
labels that refer to locations not designated
as absolute addresses by a compiler or
assembler.
futurist
A person who tries to anticipate or predict,
based on current technology and trends, what
will be accomplished in a given field in the next
several years or decades.
fuzz A form of deliberate distortion in the waveform
produced by an electric guitar.
fuzzbox A circuit that distorts the waveform produced
by an electric guitar, for the purpose of creating
various musical sound effects.
fuzz buster Slang for a specialized mobile radio receiver,
used by drivers of vehicles to signal the
presence of law-enforcement radar equipment.
fV Abbreviation of femtovolt.