US5517481A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical recording and reproducing apparatus wherein data is recorded by stepwise shifting the edge position of each pit
Assignee: Sony Corp
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Filing: 1994-06-29
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Granted: 1996-05-14
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Expires: 2014-06-29
Abstract
Abstract An information recording medium on which digital information is recorded while the edge position of each pit on the recording medium is stepwise shifted from a predetermined reference position in accordance with a code being recorded within a predetermined shift period shorter than a transient period of a reproduced signal, and an information reproducing apparatus for reproducing the recorded information from the recording medium, includes clock generating element for generating a clock synchronized with a reference position in phase on the basis of a reproduced signal obtained from the optical detection system, level detection element for detecting the reproduction level within the transient period of the reproduced signal at a timing defined by the clock, first decoding element for decoding recording data corresponding to the shift amount of the edge position of an information pit, correction value generating element for storing predetermined correction values to correct errors in a decoding operation, and outputting a correction value in correspondence with the data decoded by said first decoding element, adding element for adding the correction value with the reproduction level of a target code to be decoded, and second decoding element for decoding the recording data corresponding to the shift amount of the edge position of the information pit on the basis of the output of the adding element.
Inventors
- 👤 Seiji Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 00:17
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/26; G11B20/00; G11B20/10; G11B20/10009; G11B20/10046; G11B20/10212; G11B20/10037; G11B7/004; G11B7/005
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
236 words
An information reproducing apparatus for reproducing an information recording medium on which digital information is recorded while the edge position of an information pit is stepwise shifted from a predetermined reference position in accordance with a code being recorded within a predetermined shift period shorter than a transient period of a reproduced signal, which is determined in accordance with a transfer characteristic of an optical detection system for scanning a recording medium with a light beam along an information pit array, including: clock generating means for generating a clock which is synchronized with a reference position in phase on the basis of a reproduced signal obtained from said optical detection system; level detection means for detecting the reproduction level within the transient period of the reproduced signal at a timing defined by the clock; first decoding means for decoding recording data corresponding to the shift amount of the edge position of an information pit; correction value generating means for storing predetermined correction values to correct errors in a decoding operation, and outputting a correction value in correspondence with the data decoded by said first decoding means; adding means for adding the correction value with the reproduction level of a target code to be decoded; and second decoding means for decoding the recording data corresponding to the shift amount of the edge position of the information pit on the basis of the output of said adding means.
Claim 2
Dependent Claim
236 words
An information reproducing apparatus for reproducing an information recording medium on which digital information is recorded while the edge position of an information pit is stepwise shifted from a predetermined reference position in accordance with a code being recorded within a predetermined shift period shorter than a transient period of a reproduced signal, which is determined in accordance with a transfer characteristic of an optical detection system for scanning a recording medium with a light beam along an information pit array, including: clock generating means for generating a clock which is synchronized with a reference position in phase on the basis of a reproduced signal obtained from said optical detection system; level detection means for detecting the reproduction level within the transient period of the reproduced signal at a timing defined by the clock; first decoding means for decoding recording data corresponding to the shift amount of the edge position of an information pit; correction value generating means for storing predetermined correction values to correct errors in a decoding operation, and outputting a correction value in correspondence with the data decoded by said first decoding means; adding means for adding the correction value with the reproduction level of a target code to be decoded; and second decoding means for decoding the recording data corresponding to the shift amount of the edge position of the information pit on the basis of the output of said adding means.
Claim 3
Dependent Claim
35 words
The information reproducing apparatus as claimed in claim 1, wherein said correction value generating means generates a correction value to correct the intersymbol interference caused by a code which is adjacent to the target code.
Claim 4
Dependent Claim
40 words
The information reproducing apparatus as claimed in claim 2, wherein said correction value generating means beforehand generates correction values with the reproduction levels of educational pits which are provided as information pits to obtain decode values of all edge patterns.
Claim 5
Dependent Claim
22 words
The information reproducing apparatus as claimed in claim 3, wherein at least 64 of educational pits are provided on the disc medium.
Claim 6
Dependent Claim
101 words
The information reproducing apparatus as claimed in claim 3, wherein said correction value generating means includes a first memory for storing a first correction value to correct the intersymbol interference caused codes which are located adjacently before and after the target code, and a second memory for storing a second correction value to correct the intersymbol interference caused by codes which are located at front and rear sides of the target code and each of which corresponds to a second code from the target code, and wherein said adding means adds the reproduction level with the first and second correction values.
Claim 7
Dependent Claim
38 words
The information reproducing apparatus as claimed in claim 3, wherein a plurality of groups each comprising said first decoding means, said correction value generating means and said adding means are connected to one another in a cascade connection.
Claim 8
Dependent Claim
35 words
The information reproducing apparatus as claimed in claim 6, wherein at all of the plurality of groups of the cascade-connection, signals to be corrected are reproduced signals which are obtained from an optical detection element.
Claim 9
Dependent Claim
47 words
The information reproducing apparatus as claimed in claim 7, wherein the target code to be supplied to said adding means in all of the plurality of groups are substantially the same code which is not added with the correction value at any adding means of any stage.
Claim 10
Dependent Claim
24 words
The information reproducing apparatus as claimed in claim 8, wherein the number of groups of the cascade-connected groups is set to an even number.
Claim 11
Dependent Claim
37 words
The information reproducing apparatus as claimed in claim 1 or 9, further including altering means for altering the correction value of said correction value generating means by feeding back the output result of said second decoding means.
Claim 12
Dependent Claim
67 words
The information reproducing apparatus as claimed in claim 10, wherein said altering means includes ideal value calculating means for calculating the ideal reproduction level from the output of said second decoding means, and difference means for calculating a difference value between the ideal reproduction level and the actual reproduction level to alter the correction value of said correction value generating means in accordance with the difference value.
Claim 13
Dependent Claim
52 words
The information reproducing apparatus as claimed in claim 11, wherein said altering means includes multiplying means for multiplying the difference value by a constant to prevent oscillation of the correction value of said correction value generating means, and limiter means for limiting the output of said multiplying means within a predetermined range.
Claim 14
Dependent Claim
59 words
The information reproducing apparatus as claimed in claim 9, further including detection error correcting means for detecting presence or absence of an error for the output of said second decoding means and correcting the error, and altering means for altering the correction value of said correction value generating means in accordance with a decode value after the error correction.
Claim 15
Dependent Claim
79 words
The information reproducing apparatus as claimed in claim 13, wherein said altering means includes ideal value calculating means for calculating the ideal reproduction level from the output of said correction means, difference means for calculating the difference value between the ideal reproduction level and the actual reproduction level, and selection means for selecting any one of the difference value of said difference means and a predetermined constant in accordance with the result of said error detecting and correcting means.
Claim 16
Dependent Claim
43 words
The information reproducing apparatus as claimed in claim 14, wherein said selection means selects the difference value of said difference means when no error is detected by said error detecting and correcting means, and selects the predetermined constant when any error is detected.
Claim 17
Dependent Claim
46 words
The information reproducing apparatus as claimed in any one of claims 1 to 15, wherein said correction value generating means generates a correction value which is varied in accordance with a rotational position of the disc medium which is sectioned into a predetermined number of parts.
Claim 18
Dependent Claim
31 words
The information reproducing apparatus as claimed in claim 16, wherein pits providing initial values of said correction value generating means are collectively recorded in a predetermined area of the disc medium.
Claim 19
Dependent Claim
39 words
An information recording medium which is recorded by the information reproducing apparatus as claimed in claim 17, wherein the initial values to alter the correction value of said correction value generating means are collectively recorded in a predetermined area.
References Cited (Backward Citations)
JPS623445A
Cited
JPS6348617A
Cited
US4873680A
Cited
JPS63231733A
Cited
JPS63298818A
Cited
JPH01185839A
Cited
JPH01263964A
Cited
JPH0366735A
Cited
US5414689A
Cited
US5345434A
Cited
US5418770A
Cited
EP0477892A2
Cited
JPH04366426A
Cited
EP0540345A1
Cited
US5347505A
Cited
EP0593037A2
Cited
US5422865A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-05-14 | 1999-11-13 | 2000-05-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-05-14 | 2003-11-13 | 2004-05-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-05-14 | 2007-11-13 | 2008-05-14 | $7700.00 | Window Closed / Lapsed |