JPS57179953A - Optical reproducing system - Google Patents

Optical reproducing system

Info

Publication number
JPS57179953A
JPS57179953A JP56061399A JP6139981A JPS57179953A JP S57179953 A JPS57179953 A JP S57179953A JP 56061399 A JP56061399 A JP 56061399A JP 6139981 A JP6139981 A JP 6139981A JP S57179953 A JPS57179953 A JP S57179953A
Authority
JP
Japan
Prior art keywords
recording medium
reproduction
laser beam
laser
pulse modulation
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
JP56061399A
Other languages
Japanese (ja)
Inventor
Shiro Nakagawa
Toshiki Aoi
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.)
TDK Corp
Original Assignee
TDK 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 TDK Corp filed Critical TDK Corp
Priority to JP56061399A priority Critical patent/JPS57179953A/en
Publication of JPS57179953A publication Critical patent/JPS57179953A/en
Pending legal-status Critical Current

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
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam

Landscapes

  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Recording Or Reproduction (AREA)

Abstract

PURPOSE:To increase the SN ratio with increased peak value of laser beam, by irradiating a laser beam for reproduction with pulse modulation in a frequency more than twice the reproduced frequency. CONSTITUTION:A signal generator 1 turns on or off a semiconductor laser with a pulse signal in 100MHz and the laser is irradiated on a recording medium 5 via optical systems 4a and 4b. After a detected light from the recording medium 5 is photo-electriccally converted at a photodetector 6, the said pulse signal component is removed at a low pass filter 8 via an amplifier 7. Since pulse modulation is given to a laser beam 3 of the semiconductor laser 2, although the energy given to the recording medium is the same at the case without pulse modulation, the peak value is greater, the SN ratio at reproduction is increased, and this system is suitable for the reproduction of a high sensitivity recording medium.
JP56061399A 1981-04-24 1981-04-24 Optical reproducing system Pending JPS57179953A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP56061399A JPS57179953A (en) 1981-04-24 1981-04-24 Optical reproducing system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP56061399A JPS57179953A (en) 1981-04-24 1981-04-24 Optical reproducing system

Publications (1)

Publication Number Publication Date
JPS57179953A true JPS57179953A (en) 1982-11-05

Family

ID=13170026

Family Applications (1)

Application Number Title Priority Date Filing Date
JP56061399A Pending JPS57179953A (en) 1981-04-24 1981-04-24 Optical reproducing system

Country Status (1)

Country Link
JP (1) JPS57179953A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60243832A (en) * 1984-05-17 1985-12-03 Ricoh Co Ltd Optical information detecting device
JPS62287445A (en) * 1986-06-06 1987-12-14 Mitsubishi Electric Corp Optical head unit
EP0309200A2 (en) * 1987-09-22 1989-03-29 Hitachi Maxell Ltd. Optical information recording/reproducing apparatus

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60243832A (en) * 1984-05-17 1985-12-03 Ricoh Co Ltd Optical information detecting device
JPS62287445A (en) * 1986-06-06 1987-12-14 Mitsubishi Electric Corp Optical head unit
EP0309200A2 (en) * 1987-09-22 1989-03-29 Hitachi Maxell Ltd. Optical information recording/reproducing apparatus

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