NEC MultiSync V520 Service Manual page 54

Test Pattern Generation
A self-test pattern signal comes out from pin PB3/PAT. It can generate a cross hatch picture, a inverted
cross hatch picture, a whit epicture or a black picture.
8 × 8 cross hatch
White Picture
The test pattern signal is generated when SELF and ENPAT are both set to "1". This video signal will
synchronize to the free-running Hsync and Vsync, no matter which frequency is chosen. The following
diagram shows the timing relationship of cross hatch picture.
HSO
PAT
T
1
HSO
31.1kHz
47.9kHz
64kHz
T
2
VSO T
1
60.8Hz 6us
74.9Hz 5.125us
62.5Hz 3.625us
Inverted 8 × 8 cross hatch
T
1
T
3
T
2
1us
0.625us
0.875us
51
Black Picture
T
2
T
3
62.5ns
62.5ns
62.5ns