Service manual

STP 11-25R13-SM-TG
Glossary - 21
PLUGE
Back set of color bars.
polarity
A condition by which the direction of the flow of current can be determined in an electrical current.
power
The rate at which energy is expended or dissipated. Power is expressed in joules per second, more often
called watts.
preamplifier (preamp)
A high grain, low-noise amplifier intended to increase the amplitude of a weak signal.
pre-emphasis
A change in the level of some frequency components of the signal with respect to the other frequency
components at the input to a transmission system. The high frequency portion of the band is usually
transmitted at higher levels than the low frequency portion of the band.
purity
Physically complete saturation of a hue, uncontaminated by white and other colors.
quality control (QC)
The control of variation of workmanship, processes, and materials in a planned, systematic manner to
produce a consistent, uniform product.
radio frequency (RF)
An electromagnetic disturbance whose wavelength falls within the range of 33 km to 1 mm, the frequency
range of 9 kHz to 3000 GHz.
raster
A uniform rectangular pattern of light produced on the screen of a CRT with no signal present.
reference white level (RWL)
The picture signal level corresponding to specified maximum limit for white peaks.
resistance
The opposition to the movement of electrons in a circuit.
resistance-capacitance (RC)
Circuit that contains only resistors and capacitors, or only resistance and capacitive reactance.
resistor
A circuit component designed to offer a predetermined amount of opposition to electron flow.
resolution (horizontal)
The amount of resolvable detail in the horizontal direction in a picture. It is usually expressed as the
number of distinct vertical lines, alternately black and white, which can be seen in three quarters of the
width of the picture. This information normally is derived by observation of the vertical wedge of a test
pattern. A picture which is sharp and clear and shows small details has good, or high, resolution. If the
picture is soft and blurred, and small details are indistinct, it has poor or low resolution. Horizontal
resolution depends on the high frequency amplitude and phase response of the pick up equipment, the
transmission medium, and the picture monitor, as well as the size of the scanning spot.