Patent US4521816A successfully refreshed from Google Patents.
US4521816A
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Magnetic recording method for digital signal
Assignee: Kokusai Denki Electric Inc
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Filing: 1982-08-05
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Granted: 1985-06-04
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Expires: 2002-08-05
Abstract
Abstract A magnetic recording method for digital signals, and more particularly to a magnetic head driving current waveform wherein digital signals to be recorded on a magnetic tape at a high density have the waveform of the head driving current shaped in order to reduce the degradation of the waveform. That is, in a case where the period of the current reversal of the driving current is long and continues for at least 1.5 times the bit period, the amplitude of the current in the rise part of the wave is made small. The driving current of this waveform has a reduced waveform degradation, and the magnetic recording at the high density becomes possible.
Inventors
- 👤 Akihiko Kougami
- 👤 Seiichi Mita
- 👤 Toru Kirino
- 👤 Shusaku Nagahara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:44
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/10009; G11B20/10046; G11B20/10194; G11B20/14; G11B20/1403; G11B20/1407; G11B20/1419; G11B20/1423; G11B5/00; G11B5/02; G11B5/027; G11B5/035
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
138 words
In a magnetic recording method for digital signals having a predetermined bit period wherein magnetic patterns corresponding to the digital signals are recorded on a magnetic medium; the steps comprising detecting from said digital signals a recording current of an identical polarity which continues for a time at least equal to 1.5 times said bit period of the digital signals, and setting a current reversal amplitude Iv of a current reversal point at which the recording current of said identical polarity is started at a smaller level that the current reversal amplitude Io of the current reversal points from which the recording current will continue with identical polarity for less than 1.5 times the bit period of the digital signals, and wherein said smaller level of the current reversal amplitude Iv continues for a predetermined period of time.
Claim 2
Dependent Claim
138 words
In a magnetic recording method for digital signals having a predetermined bit period wherein magnetic patterns corresponding to the digital signals are recorded on a magnetic medium; the steps comprising detecting from said digital signals a recording current of an identical polarity which continues for a time at least equal to 1.5 times said bit period of the digital signals, and setting a current reversal amplitude Iv of a current reversal point at which the recording current of said identical polarity is started at a smaller level that the current reversal amplitude Io of the current reversal points from which the recording current will continue with identical polarity for less than 1.5 times the bit period of the digital signals, and wherein said smaller level of the current reversal amplitude Iv continues for a predetermined period of time.
Claim 3
Dependent Claim
29 words
A magnetic recording method for digital signals as defined in claim 1, characterized in that said smaller level of the current reversal amplitude Iv continues for 0.5-1.0 bit period.
Claim 4
Dependent Claim
30 words
A magnetic recording method for digital signals as defined in claim 1, characterized in that said current reversal amplitude Iv and said current reversal amplitude Io satisfy the relation 1<Io/Iv<1.4.
Claim 5
Dependent Claim
129 words
A magnetic recording system for digital signal having a predetermined bit period wherein magnetic patterns corresponding to said digital signals are recorded on a magnetic medium, said system comprising means for detecting from said digital signals a recording current of an identical polarity which continues for a time at least equal to 1.5 times said bit period of said digital signals, and means for setting for a predetermined period of time a current reversal amplitude Iv of a current reversal point at which the recording current of said identical polarity is started at a smaller level than the current reversal amplitude Io of the current reversal points from which the recording current will continue with identical polarity for less than 1.5 times the bit period of the digital signals.
Claim 6
Dependent Claim
129 words
A magnetic recording system for digital signal having a predetermined bit period wherein magnetic patterns corresponding to said digital signals are recorded on a magnetic medium, said system comprising means for detecting from said digital signals a recording current of an identical polarity which continues for a time at least equal to 1.5 times said bit period of said digital signals, and means for setting for a predetermined period of time a current reversal amplitude Iv of a current reversal point at which the recording current of said identical polarity is started at a smaller level than the current reversal amplitude Io of the current reversal points from which the recording current will continue with identical polarity for less than 1.5 times the bit period of the digital signals.
Claim 7
Dependent Claim
30 words
A magnetic recording system as defined in claim 4, wherein said setting means includes means for continuing said smaller level of the current reversal amplitude Iv for 0.5-1.0 bit period.
Claim 8
Dependent Claim
25 words
A magnetic recording system as defined in claim 4, wherein said current reversal amplitude Iv and said current reversal amplitude Io satisfy the relation 1<Io/Iv<1.4.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-06-03 | 1988-12-03 | 1989-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-03 | 1992-12-03 | 1993-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-03 | 1996-12-03 | 1997-06-04 | $7700.00 | Window Closed / Lapsed |