Tektronix 1740A Series, Руководство пользователя

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Glossary
Glossary–6
1740A/1750A/1760 – Series Service Manual
RGB Red, Green, and Blue. Also referred to as GBR. The three primary colors
used in color television’s additive color reproduction system. These are the three
color signals generated by the camera and used by the picture monitor to produce
a picture.
R–Y
One of the color difference signals is obtained by subtracting luminance
(Y) from the red camera signal.
Saturation
The property of color which relates to the amount of white light in
the color. Highly saturated colors are vivid, while less saturated colors have
more white mixed in and, therefore, appear pastel. For example, red is highly
saturated, while pink is the same hue, but much less saturated.
In signal terms, saturation is determined by the ratio between luminance level
and chrominance amplitude. It should be noted that a vectorscope does not
display saturation; the length of the vectors represents chrominance amplitude.
In order to verify that the saturation of the colors in a color bar signal is correct,
you must check luminance amplitudes with a waveform monitor in addition to
observing the vectors.
SCH The timing relationship between the horizontal sync pulses and the zero
crossings of the reference subcarrier (burst).
Setup In NTSC systems, video black is typically 7.5 IRE above the blanking
level. This 7.5 IRE level is referred to as the black setup level, or simply as
setup.
Subcarrier The modulation sidebands of the color subcarrier contain the R–Y
(V) and B–Y (U) information. For NTSC, subcarrier frequency is 3.579545
MHz. For PAL, subcarrier frequency is 4,433,618.75 Hz.
Synchronous Detection
A demodulation process in which the original
signal is recovered by multiplying the modulated signal with the output of a
synchronous oscillator locked to the carrier.
Termination
In order to accurately send a signal through a transmission line,
there must be an impedance at the end which matches the impedance of the
source and of the line itself. Amplitude errors and reflections will otherwise
result. Video is a 75
Ω
system, so a 75
Ω
terminator must be put at the end of the
signal path.
Time Code, Longitudinal (LTC) LTC is an 80-bit signal with information
which makes it possible to accurately identify an individual frame. The LTC
signal is typically recorded on an audio channel.
Time Code, Vertical (VITC) VITC is a signal in the vertical interval of
video, which makes it possible to accurately identify an individual field.
U
The B–Y signal after a weighting factor of 0.493 has been applied. The
weighting is necessary to reduce peak modulation in the composite signal.
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