Picture Submenu - VarTech Systems VT170CM User Manual

Picture Submenu

3.5
The Picture submenu presents a list of items that depends on the selected video source (digital,
analog RGB, S-video, or composite video). The current version of the product supports only an
analog RGB source. Accordingly, the Picture submenu contains the following functions:
Navigation Buttons
UP
DOWN
RIGHT
17.0" PowerVue User Guide
Menu Item
Brightness
Contrast
Phase
LEFT
H Position
V Position
H Size
(Frequency)
Sharpness
Use the UP or DOWN button to select the desired function.
Use the LEFT or RIGHT button to set the value of the selected function.
Use the SOURCE button once a setting has been made, and again to
return to the Main Menu.
Explanation
On a CRT monitor, the brightness control is really a black level
adjustment and is set so that the background raster is just cut
off when a black screen is displayed. On an LCD monitor, the
brightness control is a control of the backlight luminance level.
Both black and white levels change with changes in backlight
luminance. When setting this control, the analog luminance
control should be set full clockwise (maximum). The setting of
this control then becomes a limit on the range of the analog
luminance control.
The contrast adjustment is an adjustment of the gain of the
monitor's video amplifiers, or, in other words, of the range in
luminance between black and white. When analog video is
presented to the monitor, a black to white transition is
represented, ideally, by a voltage transition of 0.7V.
This is the phase relationship between transitions of the
monitor controller's internal pixel clock, and transitions of pixel
information coming from the external source. The phase
should be set after setting the horizontal size and the
frequency while observing an image presented by the external
source. Set the phase to obtain the sharpest and most distinct
vertical lines.
Set the horizontal position to center the image on the screen.
Make this adjustment after making a first adjustment of
horizontal size. It might be necessary to alternate between
horizontal size and horizontal position once or twice to obtain
the best possible image.
Set the vertical position to center the image on the screen.
This is usually the last format adjustment to be made.
The legend for this control refers to the frequency of the
monitor controller's internal pixel clock. Effectively, it is a
horizontal size control.
The sharpness adjustment is available to minimize
undesirable artifacts of the image scaling process. If the video
source is presenting an image at the monitor's native
resolution, or if the scaling mode is set for 1:1 display of the
incoming image, no scaling takes place, and the sharpness
setting will have no effect. However, if the monitor controller is
scaling the image, the sharpness can be set to obtain the best
possible image. This setting should be made while observing
a display of text.
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