Service manual

STP 11-25R13-SM-TG
Glossary - 19
hue
(1) One of the three basic color attributes, hue is the color itself-red, green, blue, yellow, and so on.
(2) The attribute of color perception that determines whether the color is red, green, blue, and so forth.
hum bars
Relatively broad horizontal bars, alternately black and white, which extend over the entire picture. Caused
by approximately 60-cycle interaction frequencies or one of its harmonic frequencies.
impedance
(1) A type of resistance to the signal flow. Important especially in matching high- or low-impedance
recorders. A high-impedance mic works properly only with a relatively short cable (a longer cable has too
much resistance), whereas a low-impedance mic can take up to several hundred feet of cable.
Impedance is also expressed in terms of high-Z or low-Z. (2) The total opposition a circuit offers to the
flow of alternating current at a given frequency.
inductance
The electrical property of a circuit that opposes any change in the current flowing through it. The ability of
a device to store energy in the form of a magnetic field.
IRE scale
An oscilloscope scale that applies to composite video levels. There is 140 IRE units in 1 volt.
jitter
A tendency toward lack of synchronization of the picture. It may refer to individual lines in the picture or
to the entire field view.
kilohertz (kHz)
A radio frequency unit equal to 1,000 cycles per second.
LC
A circuit consisting of a combination of inductances and capacitances.
light emitting diode (LED)
The active diode in all visible LED lamps, indicators, and displays.
linearity
An expression of the resemblance between the input and output signals of a circuit.
local area network (LAN)
A data communications network that allows many different computers and data processing devices to
communicate with each other.
low pass filter (LPF)
A combination of capacitance, inductance, and/or resistance, intended to produce high attenuation above
a specified frequency and little or no attenuation below that frequency. The LPF removes the Chroma
and audio signal.
luminance signal
Also called Y signal. The signal in which the amplitude varies with the luminance values of a televised
scene.
manometer
Instrument used to measure back pressure in the power amplifier compartment of a transmitter.