GX4
User Manual
43
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Contrast Ratio
：
The ratio of the high light output level divided by the low light output level. In theory,
the contrast ratio of the television system should be at least 100:1, if not 300:1. In reality, there are
several limitations. Well-controlled viewing conditions should yield a practical contrast ratio of 30:1 to
50:1.
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Colour Temperature:
The colour quality, expressed in degrees Kelvin (K), of a light source. The higher the
colour temperature, the bluer the light. The lower the temperature, the redder the light. Benchmark
colour temperature for the A/V industryinclude5000°K,6500°K,and 9000°K.
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Saturation:
Chroma, Chroma gain. The intensity of the colour, or the extent to which a given colour in any
image is free from white. The less white in a colour, the truer the colour or the greater its saturation.
Saturation is the amount of pigment in a colour, and not the intensity.
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Gamma:
The light output of a CRT is not linear with respect to the voltage input. The difference
between what you should have and what is actually output is known as gamma.
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Frame:
In interlaced video, a frame is one complete image.A video frame is made up of two fields, or two
sets of interlaced lines. In a film, a frame is one still image of a series that makes up a motion image.
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Genlock:
Allows synchronisation of otherwise video devices. A signal generator provides a signal pulses
which connected devices can reference. Also see Black Burst and Color Burst.
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Blackburst:
The video waveform without the video elements.It includes the vertical sync, horizontal
sync, and the Chroma burst information. Blackburst is used to synchronize video equipment to align
the video output.
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ColourBurst:
In colour TV systems, a burst of subcarrier frequency located on the back part of the
composite video signal. This serves as a colour synchronizing signal to establish a frequency and phase
reference for the Chroma signal. Colour burst is 3.58 MHz for NTSC and 4.43 MHz for PAL.
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Colour Bars
：
A standard test pattern of several basic colours (white, yellow, cyan, green, magenta, red, blue,
and black) as a reference for system alignment and testing. In NTSC video, the most commonly used colour
bars are the SMPTE standard colour bars. In PAL video, the most commonly used colour bars are eight full
field bars. On computer monitors the most commonly used colour bars are two rows of reversed colour
bars
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Seamless Switching:
A feature found on many video switchers. This feature causes the switcher to wait until
the vertical interval to switch. This avoids a glitch (temporary scrambling) which often is seen when switching
between sources.
●Scaling:
A conversion of a video or computer graphic signal from a starting resolution to a new resolution.
Scaling from one resolution to another is typically done to optimize the signal for input to an image processor,
transmission path or to improve its quality when presented on a particular display.
