cxa1992ar Sony Electronics, cxa1992ar Datasheet - Page 23

• Manufacturer Part Number: cxa1992ar
• Description: Rf Signal Processing Servo Amplifier
• Manufacturer: Sony Electronics

Focus Servo
The above figure shows a block diagram of the focus servo.
Ordinarily the FE signal is input to the focus phase compensation circuit through a 68k
when DFCT is detected, the FE signal is switched to pass through a low-pass filter formed by the internal
100k
leave Pin 3 open. The defect switch operation can be enabled and disabled with command.
The capacitor connected between Pin 5 and GND is a time constant to boost the low frequency in the normal
playback state.
The peak frequency of the focus phase compensation is approximately 1.2kHz when a resistance of 510k
connected to Pin 11.
The focus search height is approximately ±1.1Vp-p when using the constants indicated in the above figure.
This height is inversely proportional to the resistance connected between Pin 17 and V
this resistance also changes the height of the track jump and sled kick as well.
The FZC comparator inverted input is set to 15% of Vcc and VC (Pin 51); (Vcc – VC)
10k
10k
510k resistance is recommended for Pin 11.
resistance and the capacitance connected to Pin 3. When this DFCT prevention circuit is not used,
2200p
0.022µ
0.1µ
680k
0.1µ
52
1
3
4
2
FZC
FEO
FEI
FDFCT
FGD
FE
100k
DFCT
51k
FS3
9k
75k
FS4
FZC
68k
0.1µ
FLB
SENS
SELECTOR
5
– 23 –
40k
Focus
phase
Compensation
FSET
510k
11
0.015µ
FS2
50k
100k
8
50k
4.7µ
SRCH
11µ
22µ
FS1
Charge
up
FE_M
FE_O
15%.
EE
17
25 SENS1
6
7
resistance; however,
. However, changing
ISET
100k
60k
FOCUS COIL
CXA1992AR
is