JPS55150141A - Detecting method for control information - Google Patents

Detecting method for control information

Info

Publication number
JPS55150141A
JPS55150141A JP5812979A JP5812979A JPS55150141A JP S55150141 A JPS55150141 A JP S55150141A JP 5812979 A JP5812979 A JP 5812979A JP 5812979 A JP5812979 A JP 5812979A JP S55150141 A JPS55150141 A JP S55150141A
Authority
JP
Japan
Prior art keywords
way
circuits
cosω
perturbation
outputs
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
JP5812979A
Other languages
Japanese (ja)
Inventor
Toru Fujishima
Masao Hibi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
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 Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP5812979A priority Critical patent/JPS55150141A/en
Publication of JPS55150141A publication Critical patent/JPS55150141A/en
Pending legal-status Critical Current

Links

Landscapes

  • Automatic Focus Adjustment (AREA)
  • Optical Recording Or Reproduction (AREA)
  • Feedback Control In General (AREA)
  • Control Of Position Or Direction (AREA)

Abstract

PURPOSE: To detect two-way mutual position information of high reliability with simple constitution by making it possible to separate each control signal independently by synchronously detecting a response signal in two-way perturbation by a two-way variation signal.
CONSTITUTION: The outputs of sine-wave signal generating circuits 15b and 15a are applied to summing circuits 14a and 14b to move galvano-mirror 5 and a voice- coil type objective lens in mutually-orthogonal directions at cosω1t and cosω2t. Then, a reflected laser beam from video disk 7 is photodetected by photodetector 8 and variation components corresponding to each perturbation are extracted by BFPs 11a and 11b of ω1 and ω2 in center angular frequency and synchronously detected by synchronous detectors 12a and 12b by the use of the outputs of circuits 15a and 15b, so that focus-control and tracking control signals can independently be separated. Consequently, two-way mutual position information of high reliability is detected with the simple constitution.
COPYRIGHT: (C)1980,JPO&Japio
JP5812979A 1979-05-14 1979-05-14 Detecting method for control information Pending JPS55150141A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP5812979A JPS55150141A (en) 1979-05-14 1979-05-14 Detecting method for control information

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP5812979A JPS55150141A (en) 1979-05-14 1979-05-14 Detecting method for control information

Publications (1)

Publication Number Publication Date
JPS55150141A true JPS55150141A (en) 1980-11-21

Family

ID=13075362

Family Applications (1)

Application Number Title Priority Date Filing Date
JP5812979A Pending JPS55150141A (en) 1979-05-14 1979-05-14 Detecting method for control information

Country Status (1)

Country Link
JP (1) JPS55150141A (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5317706A (en) * 1976-08-02 1978-02-18 Philips Nv Optical recording carrier reader

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5317706A (en) * 1976-08-02 1978-02-18 Philips Nv Optical recording carrier reader

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