CX-3168
11
5
6
7
8
5
6
7
8
C
D
F
A
B
E
4) Spindle servo system
DSP
BLOCK
DIG.
EQ
MD
A3
A1
IC301
BA6859AFP
SPINDLE
MOTOR
IC201 UPD63763AGJ,UPD63761AGJ
107
20
4
6
DAC
EFM
SIGNAL
M
SPEED ERROR SIGNAL
PHASE ERROR SIGNAL
R322
18K
27
26
R320
33K
C307
0.01µ
EC
IC302
BD7962FM
ECR
SPCONT
FG
5
A2
19
21
22
Fig.13 Spindle servo block diagram
There are following modes for spindle servo.
1
Simple FG servo:
It is for maintaining the rotation of a disc to be in closer
condition of regular rotation.
The microcomputer monitors FG signal output pulse
according to the rotation of a spindle motor and controls
the drive voltage of the spindle motor.
This is used in following situation.
a) At set-up time, it is used during transition from power
ON with focus-close to rough servo.
b) It is used until recovering from out-of-focus during
playing.
2
Adaptation servo:
It is CLV servo mode of normal operation.
It takes a sample of WFCK/16 at EFM demodulation
block to check whether frame synchronized signal and
internal frame counter output agree, then generates
signal showing "agree" or "disagree". When this signal
shows "disagree" 8 times continuously, it is considered
as asynchronous and otherwise, it is considered as
synchronous. This adaptation servo selects lead-in servo
in asynchronous, and regular servo in synchronous
automatically.
3
Brake:
It is a mode for stopping a spindle motor. The
microcomputer monitors FG pulse and applies the brake
fully to certain interval (speed) and decreases the brake
level and stops it when the speed is under that.
4
Stop:
It is a mode used at the time of POWER ON and eject.
Both ends of voltage of a spindle motor is 0V at this time.
5
Rough servo:
It is a mode used at the time of carriage feed (carriage
move of long search, etc.).
It inputs which one of H level or L level to a spindle
equalizer after calculating line speed according to EFM
waveform.
Also this mode is to confirm the grating in test mode.