US4774602A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for distinguishing original of a magnetically recorded medium from its duplicates
Assignee: TDK Corp
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Filing: 1987-08-06
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Granted: 1988-09-27
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Expires: 2007-08-06
Abstract
Abstract In order to distinguish the original of a magnetically recorded medium such as floppy disc from its duplicates, the present invention proposes that the ID field part and the data field part are recorded successively in the floppy disc to be the original, and then both these ID field part and the data field part are read out successively at the time of its reproduction, thereby detecting a phase difference at the splice point of the data field part, thus being able to determine whether the floppy disc is original, or not.
Inventors
- 👤 Yoshio Mikame
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:44
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/00086; G11B5/00; G11B5/86
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
97 words
A method for distinguishing the original of a magnetically recorded medium from a duplicate, comprising the steps of; recording, in succession on said medium an ID field part and a data field part wherein the end point of said data field part constitutes a splice point; reading out said ID field part and said data field part successively in order to detect a phase difference at said splice point in said data field part; determining whether said magnetically recorded medium is said original or one of said duplicates based on said phase difference at said splice point.
Claim 2
Independent Claim
97 words
A method for distinguishing the original of a magnetically recorded medium from a duplicate, comprising the steps of; recording, in succession on said medium an ID field part and a data field part wherein the end point of said data field part constitutes a splice point; reading out said ID field part and said data field part successively in order to detect a phase difference at said splice point in said data field part; determining whether said magnetically recorded medium is said original or one of said duplicates based on said phase difference at said splice point.
Claim 3
Independent Claim
75 words
An apparatus for reading out information as recorded in a magnetic recording medium wherein said information has a ID field part and a data field part, comprising: means for reading said recorded information; detection means for detecting, at the time of the operation of said reading means, a phase difference at the gap portion between said ID field part and said data field part; means for stopping said reading when said phase difference is detected.
Claim 4
Independent Claim
75 words
An apparatus for reading out information as recorded in a magnetic recording medium wherein said information has a ID field part and a data field part, comprising: means for reading said recorded information; detection means for detecting, at the time of the operation of said reading means, a phase difference at the gap portion between said ID field part and said data field part; means for stopping said reading when said phase difference is detected.
Claim 5
Dependent Claim
68 words
A magnetic recording medium comprising: means for recording information in the format of a ID field part and a data field part; means for reading out said information and outputting a readout signal; means for detecting a phase difference at a gap part between said ID field part and said data field part wherein said detecting means outputs a signal to inhibit the outputting of said readout signal.
Claim 6
Dependent Claim
68 words
A magnetic recording medium comprising: means for recording information in the format of a ID field part and a data field part; means for reading out said information and outputting a readout signal; means for detecting a phase difference at a gap part between said ID field part and said data field part wherein said detecting means outputs a signal to inhibit the outputting of said readout signal.
References Cited (Backward Citations)
GB2112971A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-27 | 1992-03-28 | 1992-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-27 | 1996-03-28 | 1996-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-27 | 2000-03-28 | 2000-09-27 | $7700.00 | Window Closed / Lapsed |