JPS643822A - Optical disk device - Google Patents

Optical disk device

Info

Publication number
JPS643822A
JPS643822A JP15646987A JP15646987A JPS643822A JP S643822 A JPS643822 A JP S643822A JP 15646987 A JP15646987 A JP 15646987A JP 15646987 A JP15646987 A JP 15646987A JP S643822 A JPS643822 A JP S643822A
Authority
JP
Japan
Prior art keywords
circuit
output
counter
focus servo
servo lead
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
JP15646987A
Other languages
Japanese (ja)
Inventor
Kyosuke Yoshimoto
Osamu Ito
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.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
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 Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to JP15646987A priority Critical patent/JPS643822A/en
Publication of JPS643822A publication Critical patent/JPS643822A/en
Pending legal-status Critical Current

Links

Landscapes

  • Automatic Focus Adjustment (AREA)
  • Moving Of The Head For Recording And Reproducing By Optical Means (AREA)

Abstract

PURPOSE:To securely detect a focus servo lead-in surface by simple constitution by filtering the comparison output between a tracking error signal and a permissible level and detecting the focus leading-in surface through a counter. CONSTITUTION:The tracking error signal (a) is compared by a comparator circuit 100 with a positive and a negative permissible level, a digital filter circuit 200 removes noise components in the comparison result, and the counter 401 of a counter circuit 400 counts output pulses of an FF 300 responding to the filter output. This counter 401 is reset through a timer 403 when the output of the circuit 200 is ceased for a certain time and counts the output of the circuit 200 after noise components which can not be removed by the circuit 200 are removed for a certain time. Then an FF 402 generates a focus servo lead-in surface detection signal which is affected by neither the defect nor stain on a recording medium surface with a carry signal generated when the counted value reaches a specific value. Consequently, the focus servo lead-in surface is detected securely and stably by the simple constitution used in common to a tracking control circuit.
JP15646987A 1987-06-25 1987-06-25 Optical disk device Pending JPS643822A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP15646987A JPS643822A (en) 1987-06-25 1987-06-25 Optical disk device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP15646987A JPS643822A (en) 1987-06-25 1987-06-25 Optical disk device

Publications (1)

Publication Number Publication Date
JPS643822A true JPS643822A (en) 1989-01-09

Family

ID=15628428

Family Applications (1)

Application Number Title Priority Date Filing Date
JP15646987A Pending JPS643822A (en) 1987-06-25 1987-06-25 Optical disk device

Country Status (1)

Country Link
JP (1) JPS643822A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03157819A (en) * 1989-11-15 1991-07-05 Matsushita Electric Ind Co Ltd Optical disk device

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6251036A (en) * 1985-08-30 1987-03-05 Hitachi Ltd Automatic focusing control system for optical disc device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6251036A (en) * 1985-08-30 1987-03-05 Hitachi Ltd Automatic focusing control system for optical disc device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03157819A (en) * 1989-11-15 1991-07-05 Matsushita Electric Ind Co Ltd Optical disk device

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