公开(公告)号：JPH07121895A

公开(公告)日：1995-05-12

申请号：JP26918493

申请日：1993-10-27

Applicant: SONY CORP

Inventor： NISHIDA NORIO

IPC: G11B7/095

Abstract: PURPOSE:To improve the precision of a focus servo and to reduce a cost of an optical disk drive by controlling an offset voltage so that an integration value of a reflection light quantity difference at every prescribed number of revolutions of an optical disk becomes maximum. CONSTITUTION:The difference of the reflection light quantity between the mirror surface of the optical disk 10 of a sample format and a pit is detected by a quadripartite detector PD 22. The output of the PD 22 is inputted to a head amplifier 23, and an RF signal and a focus error signal FE are latched by latches 27-29, 32 through A/D converters 25, 31. By a PSP 32, the reflection light quantity difference is integrated at the every prescribed number of revolutions of the optical disk based on an ADRF signal latched by the latches 27-29, and a drive amplifier 35 is controlled through a D/A converter 34 so that the integration value becomes maximum. Thus, the automatic offset adjustment is performed, and the precision of the focus servo is improved.

公开(公告)号：JPH0620244A

公开(公告)日：1994-01-28

申请号：JP19456792

申请日：1992-06-30

Applicant: SONY CORP

Inventor： NISHIDA NORIO ,  OGIWARA KOICHIRO ,  NAKANO KATSUHIRO

IPC: G11B5/596 ,  G11B20/18 ,  G11B21/10

Abstract: PURPOSE:To realize low power consumption of a magnetic disc unit in which position control of head is carried out highly accurately through the use of a digital signal processor. CONSTITUTION:The magnetic disc unit comprises a digital signal processor(DSP) 10 for operating servo information based on a reproduction signal fed from a read/write circuit 5 to control the position of a head 4 on a magnetic disc 2 and for stopping oscillation of an oscillation circuit under sleep mode to stop provision of various clocks from a frequency division circuit thus stopping operation of the entire system.

公开(公告)号：JPH05307846A

公开(公告)日：1993-11-19

申请号：JP13794592

申请日：1992-04-30

Applicant: SONY CORP

Inventor： SAITO TAKEHIKO ,  NISHIDA NORIO

IPC: G11B21/10

Abstract: PURPOSE:To execute arithmetic processing at a high speed with plural servo loops and to enable servo control with high accuracy by forming the servo loops for each of the respective control means by time dividedly controlling plural means to be controlled. CONSTITUTION:The control response signals S1 from the plural means 28 and 9 to be controlled are converted to the control response data CS and FN which are digital data by first and second analog-to-digital converting 16, 24. The control response data CS and FN are time dividedly taken into a digital data signal processing means 25 which forms the control command data SDT 2 and SDT 1 in accordance with the CS and FN. Digital-to-analog converting means 30 and 29 convert the SDT 2 and SDT 1 to the control command signals SB 2 and SB 1 which are analog signals to time dividedly control the plural means 28 and 29 to be controlled and to form the servo loops for each of the respective means 28 and 9 to be controlled. As a result, the servo control of the plural means 28 and 9 to be controlled is executed with the simple constitution.

公开(公告)号：JPH03225684A

公开(公告)日：1991-10-04

申请号：JP2111690

申请日：1990-01-31

Applicant: SONY CORP

Inventor： NISHIDA NORIO

IPC: G11B21/08 ,  G11B21/10

Abstract: PURPOSE:To shorten access time by generating a wide-range track position signal from an address signal to be changed like a step for each track and a narrow-range track signal, and positioning a head. CONSTITUTION:Burst patterns are formed along the track on a recording medium while being displaced for every 1/2 track bits. Then, track phase signals Ux and Uy of two phases mutually different for a 1/2 track pitch are generated from signals UQ, UP, UA and UB of reverse phases reproduced from the two pairs of burst patterns with inverse phases out of these four phases by a head 11. Then, a narrow-range track position signal S1 is generated to be changed in proportion to the displacement amount of the head 11 within one track pitch by these signals Ux and Uy an address signal N1 to be changed like a step for each track is generated, and further, by using signals S1 and N1, a wide- range position signal S2 is generated to be similarly changed within a range exceeding the track pitch. When the head 11 is positioned in the breadthwise direction of the track on the medium by the signals S1 and S2, the access time can be shortened.

公开(公告)号：JPH02156426A

公开(公告)日：1990-06-15

申请号：JP31056888

申请日：1988-12-08

Applicant: SONY CORP

Inventor： NISHIDA NORIO

IPC: G11B7/013 ,  G11B7/085 ,  G11B7/09 ,  G11B21/08

Abstract: PURPOSE:To detect the access speed of an optical disk by an optical head by providing a means for detecting the information on traversing, 1st and 2nd means for forming the information on the access speed, and means for forming the information on a tracking error. CONSTITUTION:The information on the speed error Ve calculated by a subtracter 23 is converted to an analog signal by a D/A conversion circuit 24 and is supplied from a phase compensating circuit 25 to a drive amplifier 26 of an optical head 3. The access by the information Ve on the tracking error is continued until the value x latched in a latch circuit 21 falls to zero. A selecting switch 20 is selected to a system controller 19 side to hold the value x of the latch circuit 21 at zero and to close switches 31, 32 of the servo system when the zero is attained. The information Vx on the tracking error obtd. by a tracking error signal generator 9 drives the tracking coil of a biaxial actuator of the optical head 3 by the output of a drive amplifier 29 supplied from a phase compensating circuit 28 via a D/A conversion circuit 27. The light spot of the laser beam of the optical head 3 is thus controlled to exactly follow up the recording tracks TK on the above-mentioned optical disk 1.