FI921880A0 - SPAORREGLERINGSKRETS. - Google Patents

SPAORREGLERINGSKRETS.

Info

Publication number
FI921880A0
FI921880A0 FI921880A FI921880A FI921880A0 FI 921880 A0 FI921880 A0 FI 921880A0 FI 921880 A FI921880 A FI 921880A FI 921880 A FI921880 A FI 921880A FI 921880 A0 FI921880 A0 FI 921880A0
Authority
FI
Finland
Prior art keywords
focussing
photodiodes
fed
recording medium
input
Prior art date
Application number
FI921880A
Other languages
Finnish (fi)
Other versions
FI921880A (en
Inventor
Friedhelm Zucker
Christian Buchler
Heinz-Joerg Schroeder
Original Assignee
Thomson Brandt Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thomson Brandt Gmbh filed Critical Thomson Brandt Gmbh
Publication of FI921880A publication Critical patent/FI921880A/en
Publication of FI921880A0 publication Critical patent/FI921880A0/en

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B7/0901—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following only
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
    • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B7/094—Methods and circuits for servo offset compensation

Landscapes

  • Optical Recording Or Reproduction (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)
  • Valve Device For Special Equipments (AREA)
  • Noodles (AREA)
  • Semiconductor Lasers (AREA)
  • Details Of Television Scanning (AREA)
  • Luminescent Compositions (AREA)
  • Train Traffic Observation, Control, And Security (AREA)
  • Selective Calling Equipment (AREA)
  • Transforming Light Signals Into Electric Signals (AREA)
  • Moving Of The Head For Recording And Reproducing By Optical Means (AREA)
  • Electrophonic Musical Instruments (AREA)
  • Control Of Charge By Means Of Generators (AREA)
  • Vehicle Body Suspensions (AREA)
  • Medicines Containing Material From Animals Or Micro-Organisms (AREA)

Abstract

The invention concerns an optical scanning device which scans the frequency-warbled data tracks of a recording medium, the scanning light beam being reflected from the recording medium on to a four-quadrant photodetector (PD) with four photodiodes (A, B, C, D). The outputs of all four photodiodes (A, B, C, D) are added in an addition amplifier (V2). In order to be able to compensate automatically for offset voltages produced in the focussing-control loop by, for instance, temperature fluctuations, the output of the addition amplifier (V2) is connected to one input of a multiplier (M) to whose other input the track error signal is fed. The multiplier output is fed through a low-pass filter (TP) and as a compensation voltage to the focussing-control loop.
FI921880A 1989-10-28 1992-04-27 SPAORREGLERINGSKRETS. FI921880A0 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3936033A DE3936033A1 (en) 1989-10-28 1989-10-28 TRACK CONTROL
PCT/EP1990/001606 WO1991006950A1 (en) 1989-10-28 1990-09-21 Automatic track control

Publications (2)

Publication Number Publication Date
FI921880A FI921880A (en) 1992-04-27
FI921880A0 true FI921880A0 (en) 1992-04-27

Family

ID=6392484

Family Applications (1)

Application Number Title Priority Date Filing Date
FI921880A FI921880A0 (en) 1989-10-28 1992-04-27 SPAORREGLERINGSKRETS.

Country Status (14)

Country Link
EP (1) EP0497785B1 (en)
JP (1) JP2930716B2 (en)
KR (1) KR100255044B1 (en)
CN (1) CN1020010C (en)
AT (1) ATE114380T1 (en)
AU (1) AU6400590A (en)
DE (2) DE3936033A1 (en)
ES (1) ES2064762T3 (en)
FI (1) FI921880A0 (en)
HK (1) HK106595A (en)
HU (1) HU208879B (en)
MY (1) MY109481A (en)
TR (1) TR24802A (en)
WO (1) WO1991006950A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4323067A1 (en) * 1993-07-10 1995-01-12 Thomson Brandt Gmbh G factor adjustment
DE4415508A1 (en) * 1994-05-03 1995-11-09 Thomson Brandt Gmbh Scanner with adaptation

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2602019B2 (en) * 1987-03-12 1997-04-23 富士通株式会社 Optical disk device

Also Published As

Publication number Publication date
JP2930716B2 (en) 1999-08-03
HU208879B (en) 1994-01-28
HU9201299D0 (en) 1992-07-28
EP0497785B1 (en) 1994-11-23
ES2064762T3 (en) 1995-02-01
DE59007780D1 (en) 1995-01-05
KR100255044B1 (en) 2000-05-01
JPH05501328A (en) 1993-03-11
HUT60873A (en) 1992-10-28
TR24802A (en) 1992-05-01
AU6400590A (en) 1991-05-31
CN1020010C (en) 1993-03-03
MY109481A (en) 1997-02-28
ATE114380T1 (en) 1994-12-15
FI921880A (en) 1992-04-27
WO1991006950A1 (en) 1991-05-16
EP0497785A1 (en) 1992-08-12
HK106595A (en) 1995-07-07
CN1051445A (en) 1991-05-15
DE3936033A1 (en) 1991-05-02
KR920704283A (en) 1992-12-19

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Legal Events

Date Code Title Description
FD Application lapsed