Samsung DVD-HD850/XAA Service Manual page 80

Circuit Operating Descriptions
13-4 Servo
13-4-1 Outline
SERVO system of DVD is Compoced of Focusing SERVO, Tracking SERVO, SLED Linked SERVO and CLV
SERVO (DISC Motor Control SERVO).
1) Focusing SERVO : Focuses the optical spot output from object lens onto the disc surface. Maintains a uniform
distance between object lens of Pick-up and disc (for surface vibration of disc).
2) Tracking SERVO : Make the object lens follow the disc track in use of tracking error signal (created from Pick-up).
3) SLED Linked SERVO : When the tracking actuator inclines outwardly as the object lens follows the track during
play, the SLED motor moves slightly (and counteracts the incline).
4) CLV SERVO (DISC Motor Control SERVO) : Controls the disc motor to maintain a constant linear velocity
(necessary for RF signal).
13-4-2 Block Diagram
13-10
LED
1
POWER
2
GND
5
OPEN
ZIC1(Vaddis 6E)
6
ZIC1(Vaddis 6E)
CLOSE
7
TM1 TM+
4
TM+ TM1
3
SP+ SP+
10
SP- SP-
11
8
9
26 25 13 14
28
27
FIC1
18
17
15
16
Fig.13-14
7
11
10
6
4
20
7
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