temporal averaging
averaging a signal in
the time domain. For discrete signals, tem-
poral averaging by a finite impulse response
filter is a way to smooth out the signal.
temporal frequency
a frequency that rep-
resents the change of an image with time;
temporal frequency components can result
from motion between completed images or
from the methods used to construct a com-
plete image. A monochrome interlaced tele-
vision frame requires two (2) fields or 30 Hz
temporal frequency in constructing a com-
plete monochrome television frame. Simi-
larly, the NTSC color subcarrier frequency is
interlaced with the horizontal line frequency
and creates a 15 Hz temporal frequency com-
ponent to the color television frame.
temporal locality
See
locality
.
temporal resolution
the ability to resolve
two closely spaced targets in the time do-
main. See also
resolution
.
temporary fault
a fault that will not re-
occur if the equipment is deenergized and
then reenergized. An example of a tempo-
rary fault is when a lightning stroke causes
an uninsulated overhead line to arc over an
insulator, with no equipment damage.
temporary interruption
a loss of voltage
of less than 0.1 pu for a duration of 3 seconds
to 1 minute.
terahertz (THz)
a frequency unit, 10
12
hertz.
terminal bushing
See
bushing
.
termination
a circuit element or device
placed at the end of a transmission line that
reflects and/or absorbs signal energy.
terminator
(1) a device connected to the
physical end of a signal line that prevents the
unwanted reflection of the signal back to its
source.
(2) a data item in a stream that marks the
end of some portion or all of the data.
ternary logic
digital logic with three valid
voltage levels.
tertiary winding
a third winding on a
transformer. A tertiary winding may be used
to obtain a second voltage level from the
transformer. For example, in a substation it
may be necessary to have low voltage power
for the substation equipment in addition to
the distribution voltage. Another application
of a tertiary winding is in a wye-wye three-
phase transformer. Here the tertiary is con-
nected in delta, to provide a path for the triple
harmonic components of the exciting current
and prevent distortion of the phase voltages.
tesla
a unit of magnetic flux density equal
to one weber per square meter, i.e., one volt-
second per square meter. Denoted by T. The
unit is named in honor of Nikola Tesla, an
early pioneer in the electric industry, who is
most commonly credited with building the
first practical induction motor.
Tesla, Nikola
(1856–1943) Born: Smil-
jan, Croatia
Tesla is best known as the electrical pi-
oneer who championed the use of alternat-
ing current. When Tesla first came to the
United States he worked for Edison.
He
soon split with Edison, because Tesla ap-
proached invention from a theoretical stand-
point, whereas Edison was a “trial and er-
ror” type experimentalist.
Together with
his financial backer, George Westinghouse,
they battled with Edison, who championed
the use of direct current for electrifying the
world. Tesla is also known for his many in-
ventions including the Tesla coil and the AC
induction motor. It was Westinghouse who
made a fortune from Tesla’s inventions. Tesla
was known for his eccentricities and died a
recluse in New York City.
tesselation
in the Euclidean plane, a sub-
division of that plane into polygonal cells
c
2000 by CRC Press LLC