KB9223-L Просмотр технического описания (PDF) - Samsung

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производитель

KB9223-L

RF AMP & SERVO SIGNAL PROCESSOR

Samsung 

KB9223 / KB9223-L

PRELIMINARY

RF AMP & SERVO SIGNAL PROCESSOR

1.7 Defect Circuit

The RFO signal bottom, after being inverted, is held with two time constants of long and short.

The short time-constant bottom hold is done for a disc mirror defect more than 0.1msec, the long time-

constant bottom hold is done with the mirror level prior to the defect. By differentiating this with a

capacitor coupling and shifting the level, both signals are compared to generate the mirror defect

detection signal.

DCC1

5

DCC2

4

75K

RFO 75

37.5K -

28K

+

75K

VC+0.6254V

BOTTOM

HOLD

BOTTOM

HOLD

43K

- DFCT

41 SSTOP/DFCT

+

2

DCB

Figure 10. Defect Circuit

1.8 APC (Auto Power Control) Circuit

The laser diode has large negative temperature characteristic in its optical output when driven with a

constant current on laser diode. Therefore, the output on processing monitor photo diode, must be a

controlled current for getting regular output power, thus the APC (Auto Power Control) circuit is

composed.

PD 69

+

43.5K

-

1.25V

150K

5.5K

PN (From micom command)

150K +

-

150K

0.75K

70 LD

300K

LDON (From micom command)

Figure 11. APC Circuit

M/M-97-P006

20

1997. 10. 17

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