3
1.2 EXPLANATION OF EACH MOVEMENT
1.2.1 Sequence Up to Playback
DVD SETUP
RF AGC ON
SPDL ACCEL
Yes
Focus Lock
LD ON
Sweep UP
→
Down
ATB ON
Layer Det.
Lead-in Search
PLAY
MIRR Modulation
Measurement
T Servo ON
SLDR Servo ON
F Gain Adj.
T Gain Adj.
AFB Adj.
(Auto Focus Bias)
3
32
35
54
44
49
4
1
2
26
27
54
5
6
7
8
11 12
22
OEIC
PICKUP
CD
DVD
FDO
LDON
FE
UP
DRF
(FOK)
IC101
RFIC
IC201
DIGITAL
SERVO IC
IC501
MECH.
CONTROL
IC151
DRIVER
• FOCUS SERVO
• FOCUS LOCK TIMING
PH
RF
B1
B2
B3
B4
LD
MD
FOCUS
COIL
FE
OEIC GAIN
LASER
ADDRESS
&
BUS
SGC
FDO
DRF
58
31
13
UP
1.2.2 Focus Servo
FE generated in the RF IC is sent to the
Digital servo IC.
For a DVD, the servo is turned on during
the transition from “Up” to “Down” of
the first-order sine wave. For a CD, it
turns on during the transition from
“Down” to “Up” of the first-order sine
wave.
When the servo is turned on, the level of
PH (the envelope of the bright side of RF)
increases, and DRF becomes H. The
kick-brake pulses, such as those for
FOCUS jump, are also output from pin
49 of IC201.