3, LD ON

CL8830A LD ON command issued by the internal APC circuit 2550 , so 2550 ( 2 ) feet from high to low , Q1 turns on, the laser diode light .

4 , focusing, tracking servo

After the light of the laser diode , CPU automatically start the focus search procedure , the control 3068 disconnects the internal focusing, tracking path from ( 31 ) , ( 32 ) outputs the focus search signal for driving the objective lens substantially vertical movement , if disc, through the light - electricity conversion, amplification process , when the laser intensity reaches the set value , the spindle motor starts to rotate into constant linear velocity .

5 , the spindle servo

Once the spindle motor is started , the speed will be slow to fast , drive disc reaches the set value , disconnect the auto-focus search program , turn the focus tracking loop , then the RF signal from 2550 ( 15 ) 3068 feet out into the conduct EFM demodulation, the internal frame synchronization separation circuit 3068 is separated from the EFM demodulating circuit output data stream of the frame sync signal 7.35KHZ , the crystal frequency reference signal generated 7.35KHZ compares the error signal from the CLV processed into spindle servo control error signal , from 25 feet out into the BA6392 (24) feet, then by ( 26 ) , ( 27 ) pin output drive spindle motor. It showed the normal operation of the spindle must have a minimum of four conditions :

a, good RF signal to produce sustained FOK signal ;

b, 3068 DSP circuit demodulates the internal clock must be accurate reconstruction ;

c, the standard clock frequency generated by the crystal must be accurate ;

d, and the motor driver chip must be good .

6 , the read TOC

Good and stable spindle speed to make the pickup head TOC track information on the lead-in area of the disc , through the pre- amplification, demodulation after being stored at the same time show the total number of tracks , time and other information on the screen .

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