Video Test Generator User Guide

32 Chapter 2 Testing Video Displays
Determine the images to test:
For analog CRTs you typically want to select images to test for geometry, focusing,
photometry, resolution, cross talk, EMI, and regulation characteristics. For more details on
what images test these specific display attributes, see “Selecting images” on page 28 or
Appendix B, “Image Reference.”
Verify the test set-up:
1. Using the Format knob, select one of the formats you have identified.
Alternatively, you can load the format with the following command:
FMTL format_name; FMTU
2. Using the Image knob, select a suitable image such as ColorBar. Verify that the display
is presenting the image to ensure that the generator is sending a valid signal to the
display.
Alternatively, you can load the image with the following command:
IMGL ColorBar; IMGU
Test the display:
1. Using the Format knob, select the first test format identified.
Alternatively, use these commands to load the format:
FMTL format_name; FMTU
2. Using the Image knob, select the first test image.
Alternatively, you can also load an image with the following command:
IMGL image_name; IMGU
3. Repeat steps 1 and 2 for all formats and test images. Use the following guidelines to
verify proper operation:
• When testing geometry with the Hatch images (for example, Hatch20) look for
distortion with concave or convex lines near the periphery of the display. Look for
irregular spacing on the cross hatch patterns.
• When testing photometry such as chrominance, use the ColorBar, SMPTE133, or
SMPTEbar images. Look for missing bars which may indicate a dead or
unconnected channel. Also, look at the transition between the bars; they should be
sharp and distinct. Each bar also should be uniform in color and intensity across its
entire width.
• To test luminance, you can use the SMPTE133 (grayscale portion) image. To test
gamma correction, you can use the SMPTE133 (checkerbox portion) image. The
detailed methods for verifying these parameters on the SMPTE133 image are
provided in Appendix B, “Image Reference.”
• When testing focus with the Focus or Text images, the characters in all areas of the
display should be well-formed and in focus.