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Input signal
Symbol
Horizontal position
adjustment maximum
variable width
HPHstep
LA76850
Test point
22
28
Input signal
Y IN:
Horizontal/
vertical sync
signal
PAL
Test method
With H PHASE: 0 to 31 varied, measure the delay
time from to the rise of the pin 22 horizontal output
pulse to the fall of the Y IN horizontal sync signal
and calculate the variation at each step. Retrieve
data for maximum variation.
Bus conditions
H PHASE: 00000
to
H PHASE: 11111
Measuring
Horizontal blanking
left variable range@0
BLKL0
20IRE
Horizontal output
2.5V
Y IN:
Measure the time T from the left end of Hsync at BLKL: 000
22
Horizontal/
pin 28 Y IN to the left end of blanking at pin 17
vertical sync BlueOUT with BLKL = 000.
signal
28
PAL
Y IN
Hsync
T
Blue
Horizontal blanking
left variable range@7
BLKL7
Y IN:
Measure the time T from the left end of Hsync at BLKL:111
17
Horizontal/
pin 28 Y IN to the left end of blanking at pin 17
vertical sync BlueOUT with BLKL = 111.
signal
28
PAL
Y IN
Hsync
T
Blue
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NoA0017-18/31