Dynamic magnetic information storage or retrieval – Modulating or demodulating
Reexamination Certificate
1999-08-02
2001-10-16
Faber, Alan T. (Department: 2753)
Dynamic magnetic information storage or retrieval
Modulating or demodulating
C360S271100, C360S281000, C360S064000, C360S046000, C360S053000, C360S319000
Reexamination Certificate
active
06304397
ABSTRACT:
This application claims priority to Japanese Patent Applications 9-274557 filed Oct. 7, 1997 and 10-001135 filed Jan. 6, 1998.
The present invention relates to a helical scan magnetic recording/reproducing apparatus incorporating a magnetoresistance-effect magnetic head which serves as a reproducing magnetic head thereof.
Magnetic recording/reproducing apparatuses, such as video tape recorders, audio tape recorders and data storage systems for computers, each of which uses a magnetic tape which serves as a recording medium, are adapted to a helical scan method to raise the recording density so as to enlarge the capacity.
The magnetic recording/reproducing apparatuses of the foregoing type have been required to further raise the recording density and enlarge the capacity. To furthermore raise the recording density and enlarge the capacity, a method has been contrived which uses a helical scan magnetic recording/reproducing apparatus which incorporates a magnetoresistance-effect magnetic head (hereinafter called an “MR head”) to serve as a reproducing magnetic head.
The MR head is a magnetic head incorporating a magnetoresistance effect device (hereinafter called an “MR device”) which serves as a magnetic sensor for detecting a magnetic field of a recording medium. The MR head has been put into practical used as a reproducing magnetic head for a hard disc drive. In general, the MR head having sensitivity superior to that of an inductive-type magnetic head permits a great reproduction output to be obtained. When the MR head is employed as the reproducing magnetic head, a higher recording density and a larger capacity can be realized.
The hard disc drive incorporates the MR head mounted on a float slider to reproduce data in a state in which the MR head is floated on the magnetic disc. On the other hand, when the MR head is adapted to the helical scan method, data is reproduced from a magnetic tape in a state in which the MR head slides on the magnetic tape.
If the MR head slides on the magnetic tape, great variations in the reproduction output levels take place and noise is caused excessively in spite of great reproduction output obtainable from the MR head. Therefore, there arises a problem in that stable outputs cannot be obtained. Another problem arises in that any reproduced signal is not output, that is, dropouts frequency occur. Therefore, a helical scan magnetic recording/reproducing apparatus incorporating the MR head which serves as the reproducing magnetic head has not been put into practical use.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a helical scan magnetic recording/reproducing apparatus incorporating an MR head which serves as a reproducing magnetic head and permitting stable reproduction outputs to be obtained.
A magnetic recording/reproducing apparatus according to the present invention is a helical scan magnetic recording/reproducing apparatus comprising an MR head mounted on a rotational drum; a high-pass filter; and demodulating means. The MR head is mounted on the rotational drum so that a reproduction signal is detected from a magnetic tape on which data converted into DC-free code trains has been recorded. The high-pass filter attenuates low-frequency components contained in the reproduction signal detected by the MR head. The demodulating means demodulates data in a state in which data has been converted into the DC-free code trains from the reproduction signal, the low-frequency components of which have been attenuated by the high-pass filter.
When data is reproduced from a magnetic tape by causing the magnetic tape and the MR head to slide each other, noise contained in the reproduced output from the MR head generally contains a multiplicity of low-frequency components. The magnetic recording/reproducing apparatus according to the present invention incorporates the high-pass filter which attenuates the low-frequency components contained in the reproduced signal detected by the MR head. Therefore, the magnetic recording/reproducing apparatus according to the present invention is able to efficiently remove noise contained in the reproduced signal detected by the MR head. Moreover, data which is reproduced by the magnetic recording/reproducing apparatus according to the present invention is data converted into the DC-free code trains. Therefore, data can reliably be reproduced if the high-pass filter attenuates the low-frequency component.
REFERENCES:
patent: 2-46506 (1990-02-01), None
patent: 9-251606 (1997-09-01), None
Ikegami Tomohiro
Kamatani Yoshiteru
Ozue Tadashi
Saito Takehiko
Shirai Toshio
Faber Alan T.
Sonnenschein Nath & Rosenthal
Sony Corporation
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