JPS6476539A - Device for detecting abnormality of focus servo - Google Patents

Device for detecting abnormality of focus servo

Info

Publication number
JPS6476539A
JPS6476539A JP23526187A JP23526187A JPS6476539A JP S6476539 A JPS6476539 A JP S6476539A JP 23526187 A JP23526187 A JP 23526187A JP 23526187 A JP23526187 A JP 23526187A JP S6476539 A JPS6476539 A JP S6476539A
Authority
JP
Japan
Prior art keywords
focus servo
abnormality
recording medium
detect
read
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.)
Granted
Application number
JP23526187A
Other languages
Japanese (ja)
Other versions
JPH0778895B2 (en
Inventor
Takumi Yasujima
Kazuo Shibuya
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.)
Panasonic Mobile Communications Co Ltd
Original Assignee
Matsushita Communication Industrial Co 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 Matsushita Communication Industrial Co Ltd filed Critical Matsushita Communication Industrial Co Ltd
Priority to JP62235261A priority Critical patent/JPH0778895B2/en
Publication of JPS6476539A publication Critical patent/JPS6476539A/en
Publication of JPH0778895B2 publication Critical patent/JPH0778895B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Landscapes

  • Optical Recording Or Reproduction (AREA)
  • Automatic Focus Adjustment (AREA)

Abstract

PURPOSE:To accurately detect the abnormality of focus servo in a short time by reading data pre-formatted on a recording medium, and judging a case where the data is impossible to be discriminated within a prescribed time as the abnormality of the focus servo. CONSTITUTION:An SMD signal reproduced by a head in a recording are reproducing mechanism 16 is read, and the value SMD1 is stored in a RAM15. Next, a timer with a time (t) to detect the abnormality of the focus servo is started, and the SMD signal is read again, and the value SMD2 is stored in the RAM15, then, the values SMD1 is compared with the SMD2. Thus, the data pre-formatted on the recording medium is read, and the case where the data is impossible to be discriminated within the prescribed time is judged as the abnormality of the focus servo. In such a way, it is possible to detect the abnormality of the focus servo in a short time and accurately in spite of the eccentricity of the recording medium or the ON/OFF of tracking servo.
JP62235261A 1987-09-18 1987-09-18 Focus servo abnormality detection device Expired - Fee Related JPH0778895B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP62235261A JPH0778895B2 (en) 1987-09-18 1987-09-18 Focus servo abnormality detection device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP62235261A JPH0778895B2 (en) 1987-09-18 1987-09-18 Focus servo abnormality detection device

Publications (2)

Publication Number Publication Date
JPS6476539A true JPS6476539A (en) 1989-03-22
JPH0778895B2 JPH0778895B2 (en) 1995-08-23

Family

ID=16983466

Family Applications (1)

Application Number Title Priority Date Filing Date
JP62235261A Expired - Fee Related JPH0778895B2 (en) 1987-09-18 1987-09-18 Focus servo abnormality detection device

Country Status (1)

Country Link
JP (1) JPH0778895B2 (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5942672A (en) * 1982-09-02 1984-03-09 Toshiba Corp Disc device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5942672A (en) * 1982-09-02 1984-03-09 Toshiba Corp Disc device

Also Published As

Publication number Publication date
JPH0778895B2 (en) 1995-08-23

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Legal Events

Date Code Title Description
LAPS Cancellation because of no payment of annual fees