18WuD2x

126 collector voltage • color fringing
COLLECTOR VOLTAGE and DC COLLECTOR
VOLTAGE.
collimated rays Electromagnetic waves made parallel
or nearly parallel. This can be done by
means of a reflector, a lens, or a laser.
collimation 1. The process of rendering electromagnetic
rays parallel. 2. Adjustment of the line
of sight of an instrument, such as a level or transit.
collimation equipment Optical-alignment equipment.
collimator A device for producing parallel rays of
light or other radiation. In electronics, the most
common example is a dish antenna.
collinear antenna A broadside directional antenna
consisting of two or more half-wave radiators;
the current is kept in phase in each section by
quarter-wave stubs between each radiating section.
The radiators are stacked end to end horizontally
or vertically. Also called FRANKLIN ANTENNA.
Collins coupler A single-section, pi-filter circuit,
used to match a radio transmitter to a wide range
of antenna impedances. Also called pi coupler and
Collins network.
collodion A viscous solution of pyroxylin and a
solvent (such as acetone, alcohol, or ether) sometimes
used as a binding agent for coils and other
components.
cologarithm Abbreviation, colog. The logarithm of
the reciprocal of a number; colog x = log (1/x) =
log x –1 = –log x.
color A perceived characteristic, and a direct function,
of visible-light wavelength. Seen by the human
eye as a spectrum of hues, ranging from red
at the longest visible wavelengths, through orange,
yellow, green, blue, indigo, and finally violet
at the shortest visible wavelengths. See HUE.
coloration In audio applications, a blending of
sounds as a result of mixing among components
at different frequencies. Sometimes this is done
deliberately; in other instances, it is undesirable.
color balance In a color television receiver, adjustment
of the beam intensities of the individual
guns of a three-gun picture tube. Compensates
for the difference in light emissivity of the red,
green, and blue phosphors on the tube screen.
color bar-dot generator A radio-frequency (RF)
signal generator that produces a bar or dot pattern
on the screen of a color television picture
tube. Used for testing and alignment.
color-bar pattern A color television test pattern of
vertical bars—each of a different color.
color breakup A transient separation of a color
television picture into its red, green, and blue
components, as a result of a sudden disturbance
of viewing conditions (blinking of eyes, moving of
head, intermittent blocking of screen, etc.).
color burst As a phase reference for the 3.579545-
MHz oscillator in a color television receiver, approximately
nine cycles of the chrominance
subcarrier added to the back porch of the horizontal
blanking pedestal in the composite color
signal.
color carrier See CHROMINANCE SUBCARRIER.
colorcast A color television broadcast.
color code 1. A system that uses colored stripes or
dots to mark the nominal values and other characteristics
on capacitors, resistors, and other
components. 2. A code that represents the various
frequencies being used by radio-control modelers
in competition, and used on flags attached
to transmitters, for example, as a safeguard
against jamming.
color coder See COLOR ENCODER.
color contamination In a color television system,
faulty color reproduction resulting from incomplete
separation of the red, green, and blue channels.
color-coordinate transformation In a color television
system, the computation (performed electrically
in the system) of the tristimulus (primary)
values with reference to one set of primaries, from
the same colors derived from another set of primaries.
color depth An expression for the extent to which
an image can accurately render color. Generally
expressed in bits or in number of colors. Some
systems can reproduce millions of different colors.
color-difference signal Designated B-Y, G-Y, and
R-Y. The signal resulting from reducing the amplitude
of a color signal by an amount equal to
the luminance-signal amplitude. Also see B-Y
SIGNAL, G-Y SIGNAL, and R-Y SIGNAL.
color dot 1. A phosphor spot on the screen of a
color television picture tube. 2. One of the spots
stamped on a capacitor, indicating the capacitance,
voltage, and tolerance (see COLOR CODE,
1). 3. A spot stamped on a resistor, indicating the
number of zeros to be added to the value indicated
by the color bands.
color edging In a color television picture, an aberration
consisting of false color at the boundaries
between areas of different color.
color encoder In a color television transmitter, the
circuit or channel in which the camera signals
and the chrominance subcarrier are combined
into the color-picture signal.
color equation A mathematical means of determining
the resultant color obtained by adding
primary colors in various proportions.
color fidelity The faithfulness with which a color
television system, lens, or film reproduces the
colors of a scene.
color filter A transparent plate or film that transmits
light of a desired color, and eliminates or attenuates
all other colors.
color flicker In a color television system, image instability
that occurs when the luminance and
chromaticity both fluctuate.
color fringing In a color television picture, false
color around objects, sometimes causing them to
appear separated into different colors.