38
YPM-2306ZF
3) Carriage Servo System
The carriage servo supplies the tracking equalizer’s
low-frequency component (lens position data) output to
the carriage equalizer, then, after providing a fixed
amount of gain to it, outputs the drive signal from the
LSI. This signal is then applied to the carriage motor via
the driver IC.
When the lens offset reaches a certain level during play,
the entire pickup must be moved into the forward direc-
tion. Therefore, the equalizer gain is set to the level that
allows to generate a voltage higher than the carriage
motor starting voltage. In actual operations, a certain
threshold level is set for the equalizer output by the
servo LSI so that the drive voltage may be output from
the servo LSI only when the equalizer output exceeds
the threshold level. This arrangement helps reducing
power consumption. Also, due to disc eccentricity or
other factors, the equalizer output may cross the
threshold level a number of times. In this case, the
drive voltage output from the LSI will have pulse-like
waveform.
DIG.
EQ
SD
COP
COM
IC301
BA5985FM
CARRIAGE
MOTOR
IC201 UPD63711GC
64
2
14
13
KICK, BRAKE
REGISTERS
DAC
CONTROL
FROM
TRACK. EQ
M
DRIVE ON/OFF THRESHOLD
CARRIAGE MOVED AT THESE POINTS
TRACKING DRIVE
(LOW FREQUENCY)
LENS POSITION
CRG DRIVE
(INSIDE UPD63711GC)
CRG MOTOR VOLTAGE
Fig.16 : CARRIAGE SERVO BLOCK DIAGRAM
Fig.17 : CARRIAGE SIGNAL WAVEFORM
Summary of Contents for YPM-2106ZF
Page 3: ...YPM 2306ZF 2 EXPLODED VIEWS AND PARTS LIST 2 1 CD MECHANISM MODULE 3 ...
Page 11: ...11 YPM 2306ZF ...
Page 13: ...13 YPM 2306ZF 1 2 3 4 1 2 3 4 D C B A SIDE B A CLAMP CONTROL UNIT S8 A ...
Page 19: ...19 YPM 2306ZF Grating waveform Ech Xch 20mV div AC Fch Ych 20mV div AC 45 0 75 60 30 90 ...