Extron Electronics VTG 400D_400 DVI User Guide - Manual (Page 74)

Appendix, cont’d
VTG 400D/400 DVI • Appendix A-10
and low frequency response where the perceived brightness of both horizontal and
vertical lines should be the same for a system with good frequency response.
8. Fine Crosshatch
Crosshatch patterns are traditionally used for linearity and
convergence adjustment (both static and dynamic) of CRT-based
displays. The fine crosshatch pattern consists of finely spaced lines to
create many more intersection regions for finer convergence
adjustment, skew adjustment, lens evaluation, and so forth. All three crosshatch
patterns (4x4, large, and fine) include a border which indicates the maximum
extension of the active image area for any given signal line rate.
9. PLUGE
The PLUGE (Picture Line-Up Generating Equipment) test pattern is
used for proper setup of black level (brightness control) and display
gain (contrast).
Setting Black Level
Proper setup of black level, or brightness, is important for establishing the correct
threshold where the display begins to emit light as the video signal moves away
from black (or cutoff). Setting black level too low results in the crushing of details
within the shadow regions of the image. Setting black level too high results in
washed out shadow areas. Utilize the vertical bars on each side of the pattern for
adjustment of black level.
The overall dark surround of the pattern should be as black as the “blacker-than-
black” vertical bar (-2%) when the brightness control is properly adjusted. When
the brightness control is correctly set, the remaining two vertical bars on each side
0% (Black)
+4% –2% +2% +2% –2% +4%
50%
25%
75%
100 %
95%
PLUGE Pattern Video Levels