Quantum Data 881, User Manual

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882 Video Test Instrument User Guide (Rev A.35) 645
Test Visual chroma gain adjustment
Method To perform this test, you must have a way of turning off the red and green guns in the
monitor under test. Turning off the red and green video components of the 801GX
generator’s video output will not work for this test.
This test uses the upper and central color bars. Switch off the red and green guns on the
monitor. This will produce four blue bars, separated by black bars. Adjust the chroma gain
so that the brightness of each outer blue bar is uniform over the entire bar. The gain is
correct when the bottom 10% of each bar is the same brightness as the rest of the bar.
Test Visual chroma phase adjustment
Method In order to perform this test, you must have a way of turning off the red and green guns in
the monitor under test. Turning off the red and green video components of the 801GX
generator’s video output will not work for this test.
This test uses the upper and central color bars. Switch off the red and green guns on the
monitor. This will produce four blue bars, separated by black bars. Adjust the chroma
phase so that the brightness of each of the two central blue bars is uniform over the entire
bar. The phase is correct when the bottom 10% of each bar is the same brightness as the
rest of the bar.
Test Visual black level adjustment
Method This test uses the lower right hand portion of the image. Reduce the black level until the
gray bar disappears. Slowly increase the black level until the bar just becomes clearly
visible.