Sencore VP300 - Manual (Page 24)

Page 23
Note: The environment surrounding a TV affects the proper setting of the user controls. Room
lighting should be adjusted to the preferred level for movie viewing before the TV is calibrated.
When the Pluge pattern is selected with the NTSC format, the VP300 automatically displays an
NTSC pluge pattern with a 7.5 IRE black setup level. When an HDTV format is selected, the
VP300 displays an HDTV pluge pattern, without black setup.
To adjust the brightness control on an NTSC or HDTV display device with the Pluge pattern,
watch the second box from the inside, that is alternating between black and blacker-than-black
(7.5 IRE and 3.5 IRE in NTSC, 0 IRE and –4 IRE in non-NTSC formats). Adjust the brightness
control until the black and blacker-than-black levels appear the same and no flashing can be
seen. The outer 10 IRE box should still be slightly visible. The same method is used for HDTV,
although the pattern IRE levels are different.
If the brightness level of the outer two rectangular zones does not remain constant as the second
zone from the center alternates between black and blacker than black, the display has less than
perfect DC restoration. This can be seen especially well with the brightness (black level) control
adjusted to a slightly higher than normal setting. In this case, you will need to decide, based on
the primary use of the display, whether the black level should be adjusted on a pattern with low
APL or high APL. If the display will usually be viewed in a darkened room, adjust the brightness
control with a low APL pattern, such as the Pluge pattern. If the display will usually be viewed in
a bright room, adjust the brightness control with the pluge levels in a medium or high APL
pattern, such as the SMPTE Bar pattern or one of the Window patterns set to a high IRE level.
Sharpness Control
The sharpness control is designed to enhance the fine detail in a picture, independent of picture
content. It was originally introduced in color TVs with notch filter luma/chroma separation that
removed high frequency detail in the black and white portion of the picture. The sharpness
control was designed to put some of that detail back into the picture. Most modern TVs now use
a comb filter, which doesn’t lose the high frequency luminance detail. If a comb filter is used,
there is no longer a real need for the sharpness control, however, manufacturers find it difficult to
take away a feature that consumers have seen on sets for years. If the sharpness control is
improperly adjusted, it will either add picture distortion or reduce picture resolution.
The VP300 Needle pattern works very well for adjusting the sharpness control. The Needle
pattern contains white lines running through a black background and black lines running through
a white background. These lines are commonly referred to as needle pulses. To calibrate the
sharpness control, first turn the contrast control down to about mid-scale to make the white
portions of the pattern appear gray. This light level will best show sharpness-related picture
defects.