TDA4887PS Datasheet, PDF (46/68 Pages) NXP Semiconductors – 160 MHz bus-controlled monitor video preamplifier

Philips Semiconductors
160 MHz bus-controlled monitor video
preamplifier
Product specification
TDA4887PS
3. R, G, B gains (white point)
a) Set brightness at nominal (40H)
b) Apply full video white area (700 mV)
c) Activate the computer
d) The computer will adjust the R, G, B gains to meet
the following three conditions:
x = 0.313
y = 0.329
Y = 102.8 cd/m²
For each 3 (2.8) gain increments, the computer will
decrement the black references by one step.
The effect on cathode voltages is demonstrated in Fig.23.
After step 2 the voltages at 18.8% drive are correct but not
those at 100% drive (white) and 0% (black). After step 3
the voltages at 18.8% drive have not changed but white as
well as black voltages are correct now. Any brightness
setting (−10 to +30%) relates to the individual maximum
video amplitude (black-to-white).
This alignment procedure is adaptable to DC-coupled as
well as AC-coupled cathodes.
handbook, full pagewidth ⁸⁰
cathode
voltage
(V) 70
60
50
black
18.8%
40
30
white
20
step 1:
Black level references
and gain set to 80H.
10
step 2:
Black level references
adjusted with 18.8% drive
and gain set to 80H.
0
cut-off voltage range
from black level
references
(13 × 5.75 to 13 × 3.95)
step 3:
Gain adjustment at 100% white with
automatic black level reference correction.
Cathode voltages for 18.8% drive left
unchanged.
MHB954
Fig.23 Automatic factory alignment.
2001 Oct 19
46