Canon 1000 Service Manual page 115

4. Generating Test Patterns
The video controller has a RAM area for generating test patterns; using a channel independent from that
of the video signals from the image processor PCB, the signals are synchronized for the sub scanning
direction to generate video signals.
Video signals
Address data for test patterns is generated in response to the ITOP signal, and addresses are assigned
in the RAM for gamma correction. The selected video data is read from the RAM and sent to the laser driver.
For how to use the test patterns which are generated and sample images, see chapter 7,
Troubleshooting image problems.
COPYRIGHT © 2001 CANON INC.
Video controller PCB
Test pattern
address generation
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CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
Video signal
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Figure 3-416
3. OPERATION AND TIMING
Density correction
Video signal
Test pattern
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