Page 149 - Electrical Engineering Dictionary

standard “white” is obtained by mixing the as the infinite sum of delta functions evenly
30% red, 59% green, and 11% blue color sig- spaced through time or frequency.
nals. Differences in the color saturation for
the different phosphors found in television comb-line filter filter consisting of par-
CRTs will modify the required proportions allel coupled transmission line resonators
of red, green, and blue to produce the stan- where all resonators are grounded on one
dard “white.” side and capacitively loaded to ground on the
other. Adjacent resonators are grounded on
color-bar patterns a standard color-bar the same side. When fabricated as strip con-
pattern for an NTSC video signal consisting ductors in microstrip or stripline form, the
of a composite video signal containing a 77% metalized patterns have the appearance of a
and a 100% white chip, and yellow, cyan, comb.
green, magenta, red, blue, and black chips.
These patterns represent ideal color and lu- combination tone various sum and dif-
minance levels that can be input in a video ference frequency that are generated when
system for setting levels and verifying sys- two intense monochromatic fields interact
tem performance. with the same semiclassically described laser
medium.
Colpitts oscillator a particular case of an
LC-oscillator when X 1 and X 2 are capacitors combinational lock interconnections of
(hence, X m = 0), X 3 an inductance. memory-free digital elements.

column decoder logic used in a direct- combinational logic a digital logic, in
access memory (ROM or RAM) to select one which external output signals of a device are
of a number of rows from a given column totally dependent on the external input sig-
address. See also two-dimensional memory nals applied to the circuit.
organization.
combined cycle plant a gas-turbine
column distance the minimum Hamming power plant in which the exhaust gases are
distance between sequences of a specified used to heat water in a boiler to provide steam
length encoded with the same convolutional to run a turbogenerator.
code that differ in the first encoding interval.
combined field integral equation (CFIE)
column-access strobe See two-dimen- a mathematical relationship obtained by
sional memory organization. combining the electric field integral equation
(EFIE) and magnetic field integral equation
comb filter an electric wave filter that ex- (MFIE). It is normally used in electromag-
hibits an amplitude versus frequency plot of netic scattering calculations from a conduct-
periodically spaced pass bands interspersed ing body to avoid non-physical interior res-
with periodic stop bands. This plot resem- onances that appear by using either EFIE or
bles the teeth of an ordinary hair comb, from MFIE alone.
which the filter derives its name.
combined source-channel coding a gen-
comb function a function made of evenly eral term for approaches to source-channel
spaced, equal amplitude time or frequency coding, where the source and channel codes
components (the Fourier transform of the are combined into one overall code. In the lit-
Comb function is another Comb function). erature, the term is also used, more loosely,
The comb function is useful for discretizing for approaches where (any kind of) joint opti-
continuous signals and can be represented mization of the source and channel coding is

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