Pioneer YPM-2306ZFWL Руководство по эксплуатации - Страница 39
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4) Spindle Servo System
The spindle servo has the following modes.
1 Kick :
This mode is used for accelerating the disc rotation
during setup.
2 Offset :
(a) After the kick is over in the setup, this mode is
turned on until changing to rough servo mode.
(b) When focus is lost during play, this mode is
turned on until the focus is restored.
Both of the above are used for maintaining the disc
rotation rate near to the specified rate.
3 Applicable servo :
The CLV servo mode is turned on for the normal
operations.
In the EFM demodulation block, the frame sync sig-
nal and internal counter output signal are sampled
for every WFCK/16 and a signal is produced for indi-
cating whether or not they are matching.
They are determined to be asynchronous only when
this signal fails to match 8 times in succession. In all
other cases, above two signals are assumed to be
synchronous. In the applicable servo mode, the
retracting servo is automatically selected if the two
signals are synchronous. If not, the regular servo is
automatically selected.
4 Brake :
This mode is turned on when stopping the spindle
motor.
The microcomputer outputs the brake voltage
through the servo LSI. The LSI monitors the EFM
waveform and, if its longest pattern exceeds a cer-
tain interval (if the rotation is sufficiently slow), the
flag is set the LSI and the microcomputer turns off
the brake voltage. When the flag is not up within a
specified period time, the microcomputer switches
the mode from the brake to the stop mode, and
maintains this mode for a fixed period of time. If this
stop mode is continued for a fixed period of time,
the disc will be ejected.
5 Stop :
This mode is used for powering on the system and
the eject operation. When this mode is turned on,
voltage across the spindle motor is 0V.
6 Rough servo :
This mode is used for when the carriage feed (car-
riage mode for the long search, etc.) is turned on.
The linear speed is calculated from the EFM wave-
form and high or low level is entered to the spindle
equalizer. In the test mode, this mode is also used
for the grating check.
IC201 UPD63711GC
SPEED ERROR SIGNAL
DSP
DIG.
EFM
DAC
SIGNAL
BLOCK
EQ
PHASE ERROR SIGNAL
Fig.18 : SPINDLE SERVO MOTOR BLOCK DIAGRAM
YPM-2306ZF
IC301
BA5985FM
SOP
MD
12
SPINDLE
65
5
M
MOTOR
11
SOM
39