19
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Image controls - sharpness and brightness
The Wizard modules incorporate special controls to compensate for losses
incurred within long cable links. Using these controls you can adjust the picture
sharpness and brightness to improve your remote picture quality.
The need for image control adjustment is best discovered when viewing high
contrast images with vertical edges, such as black lines on a white background.
When doing so, if you notice that the screen image is ‘fuzzy’ or ‘dark’ then the
image controls may be able to solve this condition.
Note: If the high contrast images exhibit shadows with separate colours, then
there may be a skew problem which requires a different image adjustment - see
the ‘Skew adjustment’ section for details.
IMPORTANT: The sharpness and brightness adjustments affect ALL video
channels equally. It is important to ensure that all twisted paur link cables are of
equal length and have similar twist characteristics.
To display a suitable high contrast image
The best way to clearly view the effect of sharpness and brightness adjustments
is to display a high contrast image, with vertical edges, on the screen.
• Open a word processor, type the capital letter
‘H’, or ‘M’ and increase the point size to 72 or
higher. For best results, the background should
be white and the character should be black.
• A BLACK shadow on the right of the character
indicates UNDER compensation.
• A WHITE shadow on the right of the character
indicates OVER compensation.
To use the image controls
1 Simultaneously, press the hotkeys (by default,
and
) along with
to enter configuration mode.
The three keyboard indicators (‘Num Lock’, ‘Caps
Lock’ and ‘Scroll Lock’) will now begin to flash in
sequence. The speed of the sequence indicates the
level of the sharpness adjustment currently applied:
the slower the rate, the lower the level of sharpness
being applied.
2 While viewing the displayed high contrast screen image, use the following
keys to adjust the controls:
High contrast
black character
on white
background
Black or bright
white shadow
on the right
indicates
the need for
sharpness
adjustment
Sharpness:
for fine adjustment, for coarse adjustment.
There are 255 sharpness levels (one coarse step jumps 10 levels).
To autoset sharpness: Press to make the module calculate
and apply an automatic compensation level - you can use this as a
starting point for your fine tuning.
Note: If the monitor goes blank and switches off (due to
oversetting the sharpness adjustment) press the key to restore.
Brightness:
for adjustment. There are 255 brightness levels.
3 When no shadows are visible and the displayed images have crisp edges,
press
to exit configuration mode and permanently save all settings.
The new compensation setting will be stored, even when power is removed
or if a complete reset is initiated. The setting should not require further
changes unless the cabling arrangement is altered.
Sharpness
increase
(coarse)
Sharpness
decrease
(coarse)
Sharpness
increase
(fine)
Sharpness
decrease
(fine)
Brightness
increase
Brightness
decrease
Restore default
sharpness and
brightness
settings
Exit image
controls
and save
settings
If the image controls cannot provide a crisp image
If, after adjusting the image controls, the screen image remains
fuzzy or has coloured shadows you may need to use the Skew
adjustment feature. Please see the next section for details.
