Sony TVP-08, Training Manual

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109
Sensor Amp
Overview
The sensor amplifier is used when the customer or servicer presses the
Auto Focus button. It amplifies the signal from the sensors and outputs
the signal to the D/A converter on the BD board.
Auto Focus
The Auto Focus system works by adjusting centering and skew conver-
gence data to receive a memorized optimum level. The servicer can set
this level by performing the Auto Focus function in the Service Mode.
This means that the system does not pick a new optimum value when the
customer uses it but rather changes centering and skew adjustment data
to get an optimum sensor reading. The drawing below shows the position
of the sensors around the screen.
5
3
0
2
7
4
1
6
SCREEN
0 : UPPER SENSOR
1 : LEFT SENSOR
2 : RIGHT SENSOR
3 : LOWER SENSOR
4 : UL SENSOR
5 : UR SENSOR
6 : LL SENSOR
7 : LR SENSOR
When Auto Focus button is pressed Pattern A and B are output in suc-
cession over top of the sensors. Pattern A is offset to the left of the
sensor and Pattern B is output to the right of the sensor.
PHOTO SENSOR
PHOTO SENSOR
a
L
PATTERN A
PATTERN B
A
A + B
a
L
=
[ OVER VIEW ]
1. MEASUREMENT PRINCIPAL