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EP0430811A2
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Magneto-optical signal reproducing apparatus
Assignee: Sony Corp
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Filing: 1990-11-29
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Granted: —
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Expires: 2010-11-29
Abstract
Abstract The present invention provides a magneto-optical signal reproducing apparatus for reading out a signal recorded on a magneto-optical recording medium (10) by means of an optical pickup device (12 to 22) to provide a magneto-optical signal to level-discriminate the magneto-optical signal on the basis of a predetermined reference level to reproduce data therefrom, wherein the reference level in reproducing of the data is controlled in dependency upon a level of an in-phase signal component provided from the optical pickup (31, 32), thereby making it possible to stably reproduce data. <IMAGE>
Inventors
- 👤 Tetsu Watanabe
- 👤 Tamotsu Yamagami
- 👤 Tetsuji Kawashima
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 07:47
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/10009; G11B20/10046; G11B20/10203; G11B11/00; G11B11/10; G11B11/105; G11B11/10502; G11B11/10515; G11B20/10037
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
77 words
A magneto-optical signal reproducing apparatus for reproducing a data sequence from the magneto-optical signal provided by reading out a signal recorded on a magneto-optical recording medium by means of optical pickup device, comprising a binarization means for binarize said magneto-optical signal after the level-discrimination based on a predetermined reference level, and a reference level controlling means for controlling said reference level in dependency upon a level of an in-phase signal component provided from said optical pickup device.
Claim 2
Dependent Claim
91 words
The magneto-optical signal reproducing apparatus according to claim 1 wherein the optical pickup device comprises a pair of photo detectors for detecting a polarized light component different to each other, said polarized light component included in a reflected light from said magneto-optical recording medium, a subtracter for outputting a differential signal between the detection signals each of which is provided from said pair of photo detectors respectively, and an adder for outputting a sum signal of the detection signals each of which is provided from said pair of photo detectors respectively.
Claim 3
Dependent Claim
35 words
The magneto-optical signal reproducing apparatus according to claim 2 characterized in that said reference level controlling means determines a reference level for discriminating said differential signal in accordance with a level of said sum signal.
Claim 4
Dependent Claim
47 words
The magneto-optical signal reproducing apparatus according to claim 1 wherein said binarization means comprises a subtracter for subtracting a signal one sample period previous to said magneto-optical signal from said magneto-optical signal, and a comparator for comparing said reference level with a output signal of said subtracter.
Claim 5
Dependent Claim
50 words
The magneto-optical signal reproducing apparatus according to claim 1 wherein said reference level controlling means controls a reference level in dependency on a magneto-optical signal component and an in-phase signal component of a signal recorded on a trial writing area provided in a recording area of said magneto-optical recording medium.
Claim 6
Dependent Claim
30 words
The magneto-optical signal reproducing apparatus according to claim 5 characterized in that output power of the optical pickup device is controlled by a signal recorded on said trial writing area.
Claim 7
Dependent Claim
56 words
The magneto-optical signal reproducing apparatus according to claim 5 characterized in that said reference level is provided by multiplying said magneto-optical signal by a function corresponding to a comparison between the in-phase signal component of a signal recorded on said trial writing area and the in-phase signal component of a signal recorded on a data area.
Claim 8
Dependent Claim
20 words
The magneto-optical signal reproducing apparatus according to claim 7 characterized in that said function is previously stored in a memory.
References Cited (Backward Citations)
No citation records indexed.
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