Sencore VideoPro VP400 Series Operation Manual page 20

VP400 Series Video Pro
DecodAdj
Pattern Description:
The DecodAdj pattern contains three primary color sections with red on the top, green in the
middle and blue on the bottom. Each primary color section includes a white reference bar, and
below it, two secondary color bars in an alternating pattern of six bars. The two secondary colors
are combinations resulting from mixing the primary color and each of the other two primaries.
Pattern Usage:
Use to adjust a display's color decoder/matrix
circuit for most accurate color reproduction.
View each color primary section through its
respective red, green and blue color filter.
A chroma gain control should be adjusted to
match the intensity of the reference white bar in
each section to that of the primary color
surrounding it. A chroma hue control should be
adjusted to match the intensity of the secondary
color sections within each primary color block.
Usually, the user menu Color and Hue controls
are used to adjust the blue section, and then
service menu controls are used to adjust the red and green sections. Service menu decoder/matrix
adjustments typically include "RYR (red gain), RYB (red hue), GYR (green gain), GYB (green
hue)" adjustments, or simply a number of "axis" settings.
DecodChk
Pattern Description:
Red, green and blue primary color blocks on a 75% white background. The red and green
primary color blocks are divided into 11 sections which have decreasing color levels from left to
right. The center, or 0 sections, for each color block are the standard 75% color level included in
most test patterns. The color levels decrease in 5 % increments from the left to right.
Form7343A
Pattern Usage:
The DecodChk pattern checks the performance of
the color decoder to determine if the decoder has
red or green color emphasis (often called "push")
or de-emphasis. Ideally, with the color hue
properly set using the blue section, the 0 center
blue bar should be the same light intensity as the
surrounding 75% white, when viewed through a
blue filter. Looking through a red or green filter at
their respective color bars should show the center
0 bars at the same intensity as the 75% white area.
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Operation Manual