Dynamic magnetic information storage or retrieval – General processing of a digital signal – Head amplifier circuit
Reexamination Certificate
2000-10-26
2003-07-15
Faber, Alan T. (Department: 2651)
Dynamic magnetic information storage or retrieval
General processing of a digital signal
Head amplifier circuit
C360S068000, C360S067000, C360S065000
Reexamination Certificate
active
06594095
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic recording apparatus and an integrated circuit for magnetic recording which are suitable for use in recording data in a magnetic recording medium, in the form of a disc, or a tape.
2. Description of the Related Art
When data recording is carried out by a magnetic recording apparatus in common use, such as a magnetic disc device or a digital video tape recorder, onto a magnetic recording medium such as a magnetic disc or a magnetic tape, input data (recording signal) received from an upper apparatus or the like is amplified by an amplifier up to a level high enough to cause a flux reversal (hereinafter also called the inversion of magnetization) on the magnetic recording medium, and then recorded by a magnetic head onto the magnetic medium.
At that time, the recording signal (recording current) amplified by the amplifier takes a square waveform whose magnetic polarity is repetitively reversed (positive or negative, or “−” or “+”) depending on a sign of the data. The reversal of the polarity (hereinafter also called the inversion of magnetization) takes places each time when the recording current exceeds a predetermined magnetic polarity reversal level (hereinafter also called the magnetization inverse level).
Here, a recording signal large in amplitude elongates the time needed for reversing the polarity. In order to increase a data recording rate onto a magnetic recording medium, a conventional magnetic recording apparatus employs an amplifier having a rising time as short as possible to improve a transfer rate of the recording signal. A recording head is coupled to the amplifier, and overshoot controlling is also performed.
However, such a conventional magnetic recording apparatus still has following problems to be solved. A constant settling level of the recording signal (recording current) makes it difficult to shorten the time needed for reversing the magnetic polarity (a rising time and a falling time).
In contrast to the recent remarkable improvement in the transfer rate of the recording signal, a rising or a falling rate has not yet been improved so much. In particular, since a recording signal large in amplitude needs a long time for reversing its magnetization, it is to be afraid that, when the transfer rate of the recording signal is high, the next inversion of magnetization begins before completion of the current inversion, or before the level of the recording current reaches the magnetic inverse level, thus causing the data recording onto a magnetic recording medium to be incomplete.
SUMMARY OF THE INVENTION
With the foregoing problems in view, it is a first object of the present invention to provide a magnetic recording apparatus for magnetic recording in which a rise time and a fall time of a recording electric current are reduced, enabling a high-rate transmission of the recording current.
A second object of the present invention is to provide an integrated circuit for magnetic recording with which a rise time of and a fall time of a recording current are reduced, enabling a high-rate transmission of the recording current.
In order to accomplish the above first object, according to a first generic feature of the present invention, there is provided a magnetic recording apparatus comprising: a recording circuit for generating a recording current corresponding to an input recording signal; a magnetic head, operative in response to the generated recording current, for recording, in a magnetic recording medium, data corresponding to the input recording signal; and a waveform shaping section for shaping a waveform of the recording current in such a manner that a current value of the recording current infinitely approaches a predetermined value while keeping thereover throughout a period corresponding to the data length.
According to a second generic feature of the invention, there is provided a magnetic recording apparatus comprising: a recording circuit for generating a recording current corresponding to an input recording signal; a magnetic head, operative in response to the generated recording current, for recording, in a magnetic recording medium, data corresponding to the input recording signal; and a waveform shaping section for shaping a waveform of the input recording signal in such a manner that a current value of the recording current infinitely approaches a predetermined value while keeping thereover throughout a period corresponding to a length of the data to be recorded.
As a preferred feature, the magnetic recording apparatus further comprises a data length detecting section for detecting a pulse width of the recording current as the data length. As another preferred feature, both the waveform shaping section and the recording circuit are mounted on a common substrate. As still another preferred feature, the waveform shaping section is in the form of an integrated circuit.
According to a third generic feature, the above second object is accomplished by a magnetic recording integrated circuit for driving a magnetic head which is energized by a recording current to record, in a magnetic recording medium, data corresponding to an input recording signal, the integrated circuit comprising: a recording circuit for generating the recording current corresponding to the input recording signal; and waveform shaping section for shaping a waveform of the recording current in such a manner that a current value of the recording current infinitely approaches a predetermined value while keeping thereover throughout a period corresponding to the data length; both the recording circuit and the waveform shaping section being mounted in an integrated form on a single microchip.
The magnetic recording apparatus and the integrated circuit of the present invention guarantee the following advantageous results:
(1) Since the time needed for inversion of an electric polarity, or a rise time and a fall time, of a recording current is reduced, and particularly since the inversion of magnetization can be made rapidly even in a recording signal large in amplitude, data recording can be performed smoothly even for a high rate of transfer of the recording signal.
(2) Since the recording current infinitely approaches the magnetization inverse level, it is free of noises, reducing transition and track edge noises.
(3) A track width recorded at the lowest recording frequency can be approximate to that recorded at the highest recording frequency.
(4) Data recording can be performed while the amplitude of a recording current is kept in low level, thus reducing the electric power consumption.
(5) Downsizing of the magnetic recording apparatus can be realized.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.
REFERENCES:
patent: 6052017 (2000-04-01), Pidutti et al.
patent: 6118602 (2000-09-01), de la Soujeole
patent: 6181495 (2001-01-01), Makise et al.
patent: 52-100216 (1977-08-01), None
patent: 8287402 (1996-11-01), None
patent: 9044805 (1997-02-01), None
Uehara Yuji
Yamagishi Michinaga
Faber Alan T.
Fujitsu Limited
Greer Burns & Crain Ltd.
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