JPS643822A - Optical disk device - Google Patents
Optical disk deviceInfo
- 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
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.
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)
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)
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 |
-
1987
- 1987-06-25 JP JP15646987A patent/JPS643822A/en active Pending
Patent Citations (1)
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)
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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