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Electrical Engineering Dictionary - part 35

cold start

(1) a complete reloading of the

system with no reassumption. All executed
processes are lost.

(2) the starting of a computer system from

a power-off condition.

(3) the state from which a thermal genera-

tion unit must be brought after being in cold
reserve.

cold start miss

in a cache, a cold start

miss occurs when a computer program is ref-
erencing a memory block for the first time,
so the block has to be brought into the cache
from main memory. Also called first refer-
ence misses or compulsory misses. When
the cache is empty, all new memory block
references are cold misses. See also

capacity

miss

conflict miss

collapsible reel

a take-up reel used in line

work which fits on the power-take-off of a
line truck.

collector wall

the collector of a bipo-

lar transistor is located below the surface of
the substrate. The wall, or sidewall, is the
vertical boundary of the collector that meets
the substrate material. The boundary usually
forms a p-n junction that provides isolation
from.

collet

a circular spring fingerstock con-

nection element for a power vacuum tube.

colliding-pulse-modelocked (CPM) laser

a dye laser resonator design for producing

femtosecond pulses; right and left travelling
pulses collide in a thin intracavity absorber.

collimated

beam with nearly flat phase

fronts and slow longitudinal variations of the
transverse amplitude distribution.

collinear geometry acousto-optical tun-
able filter

acousto-optical tunable filter

device where the acoustic and light waves
propagate in the same direction. Also abbre-
viated collinear geometry AOTF.

collinear geometry AOTF

See

collinear

geometry acousto-optical tunable filter

collision

(1) in a pipeline, a situation when

two or more tasks attempt to use the same
pipeline stage at the same time.

(2) in a hash table, when

n + 1 different

keys are mapped by a hashing function to
the same table index (where

n entries can be

stored).

collision broadening

broadening of

the spectral profile of an amplifying or ab-
sorbing transition due to inelastic or phase-
interrupting elastic collisions.

collision vector

a binary number in which

the ith bit is a 1 if submitting a task into the
pipeline i cycles after a task will cause a col-
lision.

color

visual sensation associated with the

wavelength or frequency content of an optical
signal.

color blooming

phenomenon where the

excess charge at a photo receptor can spread
to neighboring receptors, and change their
values in proportion to the overload.

For

RGB cameras, this effect can modify not
only the luminance but also the chrominance
of pixels. See

color clipping

chrominance

luminance

color burst

burst of eight to ten cycles of

the 3.579545 MHz (3.58 MHz) chrominance
subcarrier frequency that occurs during the
horizontal blanking of the NTSC composite
video signal. The color burst signal synchro-
nizes the television receiver’s color demodu-
lator circuits.

color clipping

phenomenon where the in-

tensity of the light on a photoreceptor exceeds
some threshold, the receptor becomes satu-
rated and its response is no longer linear, but
limited to some bound. For RGB cameras,
this effect can modify not only the luminance

2000 by CRC Press LLC

but also the chrominance of pixels. See

color coding

the process of identifying

components’ values and tolerances by means
of a set of colored bands or dots.

color correction

in practical photome-

try it is known that the system used to mea-
sure luminescence will not possess the stan-
dard eye spectral response as specified by the
1931 International Commission on Illumina-
tion (CIE). The measurement “system” will
undoubtedly consist of a photodetector, an
optical filter and associated lenses. Unfortu-
nately, system output is highly dependent on
its spectral response.

color difference signals

the chromi-

nance signal component that results from
subtracting the luminance (Y) component
from a primary color. The luminance sig-
nal corresponds to the changes in brightness
as from a monochrome video signal. The
three primary colors for color television sig-
nals are located in Maxwell’s chromaticity
diagram. Red is at a wavelength of 0.7 mi-
crometer, green at 0.546 micrometer and blue
at 0.436 micrometer. The luminance signal
component results from the matrix addition
of the primary colors. The matrix propor-
tions are 30% red, 59% green, and 11% blue.
Two color difference signals, (R-Y) and (B-
Y) are sufficient to convey all the information
necessary to reproduce full color at the TV re-
ceiver. The color difference signal (G-Y) can
be determined by proper proportions of the
(R-Y), (B-Y) and Y signals at the receiver.

color graphics adapter (CGA)

a video

adapter proposed by IBM in 1981. It is ca-
pable of emulating MDA. In graphic mode,
it allows one to reach 640

× 200 (wide per

high) pixels with 2 colors or 320

× 200 with

4 colors.

color image coding

compression of color

images is usually done by transforming RGB
color space into a

Y C

space, where

Y rep-

resents luminance and

and

are color

difference signals. The

and

signals are

then subsampled, but coded with the same
algorithm as the

Y signal. Standard algo-

rithms do not attempt to exploit correlations
between the three signals.

color matching

the process of mixing

three fixed and independent primary colors
so that an observer (trichromat) interprets the
formulation as being the same as a speci-
fied but arbitrary color. In color television,
the three primary colors are fixed at specific
wavelengths bands

, and

corre-

sponding to colors red, green, and blue.

color preference index (CPI)

measure

appraising a light source for appreciative
viewing of colored objects or for promoting
an optimistic viewpoint by flattery.

color representation

a method of defin-

ing a signal or an image pixel value to be
associated with a color index.

color saturation

a color with the dom-

inant wavelength located at the periphery of
Maxwell’s chromaticity diagram.

A fully

saturated color is pure because it has not been
contaminated by any other color or influence.

color signal

the portion of a modulated

signal that determines the colors of the in-
tended output display.

color space

the space

C within which

colors are represented in the image function
I : R

→ C.

color temperature

the color a black ob-

ject becomes when it is heated. The stan-
dard color “white” occurs when a tungsten
filament is heated to a temperature of 6800
degrees Kelvin. The temperature of 6800 K
corresponds to a standard white raster as de-
fined by the NTSC. The color temperature for
white is useful for comparing color match-
ing and color decoding among different dis-
plays that use different color phosphors. The

2000 by CRC Press LLC

standard “white” is obtained by mixing the
30% red, 59% green, and 11% blue color sig-
nals. Differences in the color saturation for
the different phosphors found in television
CRTs will modify the required proportions
of red, green, and blue to produce the stan-
dard “white.”

color-bar patterns

a standard color-bar

pattern for an NTSC video signal consisting
of a composite video signal containing a 77%
and a 100% white chip, and yellow, cyan,
green, magenta, red, blue, and black chips.
These patterns represent ideal color and lu-
minance levels that can be input in a video
system for setting levels and verifying sys-
tem performance.

Colpitts oscillator

a particular case of an

LC-oscillator when

and

are capacitors

(hence,

= 0), X

an inductance.

column decoder

logic used in a direct-

access memory (ROM or RAM) to select one
of a number of rows from a given column
address. See also

two-dimensional memory

organization

column distance

the minimum Hamming

distance between sequences of a specified
length encoded with the same convolutional
code that differ in the first encoding interval.

column-access strobe

See

two-dimen-

sional memory organization

comb filter

an electric wave filter that ex-

hibits an amplitude versus frequency plot of
periodically spaced pass bands interspersed
with periodic stop bands. This plot resem-
bles the teeth of an ordinary hair comb, from
which the filter derives its name.

comb function

a function made of evenly

spaced, equal amplitude time or frequency
components (the Fourier transform of the
Comb function is another Comb function).
The comb function is useful for discretizing
continuous signals and can be represented

as the infinite sum of delta functions evenly
spaced through time or frequency.

comb-line filter

filter consisting of par-

allel coupled transmission line resonators
where all resonators are grounded on one
side and capacitively loaded to ground on the
other. Adjacent resonators are grounded on
the same side. When fabricated as strip con-
ductors in microstrip or stripline form, the
metalized patterns have the appearance of a
comb.

combination tone

various sum and dif-

ference frequency that are generated when
two intense monochromatic fields interact
with the same semiclassically described laser
medium.

combinational lock

interconnections of

memory-free digital elements.

combinational logic

a digital logic, in

which external output signals of a device are
totally dependent on the external input sig-
nals applied to the circuit.

combined cycle plant

a gas-turbine

power plant in which the exhaust gases are
used to heat water in a boiler to provide steam
to run a turbogenerator.

combined field integral equation (CFIE)

a mathematical relationship obtained by

combining the electric field integral equation
(EFIE) and magnetic field integral equation
(MFIE). It is normally used in electromag-
netic scattering calculations from a conduct-
ing body to avoid non-physical interior res-
onances that appear by using either EFIE or
MFIE alone.

combined source-channel coding

a gen-

eral term for approaches to source-channel
coding, where the source and channel codes
are combined into one overall code. In the lit-
erature, the term is also used, more loosely,
for approaches where (any kind of) joint opti-
mization of the source and channel coding is

2000 by CRC Press LLC

utilized. Also commonly referred to as joint
source-channel coding.

combo trouble-shooter

in combined

electric and gas utilities, a practice which is
growing in popularity is the use of combo
troubleshooters. The combo troubleshooter
is cross trained in both electric and gas ser-
vice practices. The cross functionality per-
mits more efficient deployment of resources.

come-a-long

a ratcheted winch or block-

and-tackle for pulling conductors into place.

command

(1) directives in natural lan-

guage or symbolic notations entered by users
to select computer programs or functions.

(2) instructions from the central processor

unit (CPU) to controllers and other devices
for execution.

(3) a CPU command, or a single instruc-

tion, ADD, LOAD, etc.

Commision

International

d’Eclairage

(CIE)

International standards body for

lighting and color measurement. Known in
English as the International Commission on
Illumination.

commit

the phase of a transaction in

which the new states are written to the global
memory or database.

The commit phase

should not be started until it has been veri-
fied that performing the commit will not vi-
olate the system’s consistency requirements.
In most designs, the commit phase itself must
be performed under more strict locking than
the remainder of the transaction.

Comit´e Consulatif International T´el´egra-
phique et T´el´ephonique (CCITT)

Inter-

national Consultative Committee for Teleg-
raphy and Telephony. This institution, based
in Geneva, Switzerland, issues recommenda-
tions concerning all fields related to telecom-
munications.

common base amplifier

a single transis-

tor BJT amplifier in which the input signal
is applied to the emitter terminal, the output
is taken from the collector terminal, and the
base terminal is connected to a constant volt-
age.

common centroid

a technique in

the physical design of integrated circuits
in which two transistors, which must be
matched, are actually composed of multiple
devices connected in parallel. By appropri-
ately connecting the multiple devices, the ef-
fective center (“centroid”) of the two transis-
tors can be located at the same point, thus
improving the matching in the presence of
nonidealities in the integrated circuit fabri-
cation process. See also

cross-quad

common channel signaling (CCS)

technique for routing signaling information
through a packet-switched network.

common collector amplifier

a single-

transistor BJT amplifier in which the input
signal is applied to the base terminal, the out-
put is taken from the emitter terminal, and the
collector terminal is connected to a constant
voltage. Also referred to as an emitter fol-
lower, since the voltage gain of this config-
uration is close to unity (the emitter voltage
“follows” the base voltage).

common drain amplifier

a single tran-

sistor FET amplifier in which the input signal
is applied to the gate terminal, the output is
taken from the source terminal, and the drain
terminal is connected to a constant voltage.
Also referred to as a source follower, since
the voltage gain of this configuration is close
to unity (the source voltage “follows” the gate
voltage).

common emitter

a basic transistor am-

plifier stage whose emitter is common to both
input and output loops. It amplifies voltage,
current, and hence power.

2000 by CRC Press LLC

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