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1. 发明专利

DE69812313D1 未知
公开(公告)号：DE69812313D1
公开(公告)日：2003-04-24
申请号：DE69812313
申请日：1998-12-30
申请人： HITACHI LTD
发明人： IDE HIROSHI , TOMIYAMA FUTOSHI , NISHIDA YASUTAKA , HAMAGUCHI TAKEHIKO , TAKANO HISASHI , MARUYAMA YOHJI , NAKAMURA ATSUSHI , SAWAGUCHI HIDEKI
IPC分类号： G11B5/596 , G11B7/08 , G11B5/012 , G11B19/04 , G11B21/10
摘要： An information storage apparatus having a disk medium 3 with data recording areas 203 along a plurality of tracks concentrically arranged, a head 4 for recording and reproducing data on tracks of the disk medium, an actuator 5 for moving the head to a desired track among the plurality of tracks, and an electric circuit 7 for controlling recording and reproducing and for detecting the distance from a recorded magnetization pattern on the adjacent tracks in the radial direction by detecting already recorded signals of adjacent tracks during data recording. By use of this constitution, even if the track density is increased, the upper limit of the threshold value setting range in the function for preventing from offtrack recording of the information storage apparatus can be increased and a high track density of the information storage apparatus can be easily realized.

2. 发明专利

SG65698A1 Compensating circuit equalizer and magnetic recording/reproducing apparatus using the same 未知
公开(公告)号：SG65698A1
公开(公告)日：1999-06-22
申请号：SG1997004045
申请日：1997-11-13
申请人： HITACHI LTD
发明人： NISHIDA YASUTAKA , SATOH NAOKI
IPC分类号： G11B5/00 , G11B5/02 , G11B5/035 , G11B20/10 , H04B3/04 , G11B5/127 , G11B5/39 , G11B5/33
摘要： A compensating circuit for compensating positive-negative asymmetry of an input signal having an amplitude exhibiting a positive-negative asymmetry with reference to a given level. Either one of the input signal or a signal obtained by multiplying the input signal by a given number is selected to be outputted as a compensated signal when the input signal has a level higher than a threshold level or alternatively when the input signal has a level lower than the threshold level. Distortion of signal waveforms ascribable to non-linearity of an MR head can be compensated satisfactorily with an extremely simplified and inexpensive circuit structure.

3. 发明专利

DE69812313T2 未知
公开(公告)号：DE69812313T2
公开(公告)日：2004-02-12
申请号：DE69812313
申请日：1998-12-30
申请人： HITACHI LTD
发明人： IDE HIROSHI , TOMIYAMA FUTOSHI , NISHIDA YASUTAKA , HAMAGUCHI TAKEHIKO , TAKANO HISASHI , MARUYAMA YOHJI , NAKAMURA ATSUSHI , SAWAGUCHI HIDEKI
IPC分类号： G11B5/596 , G11B7/08 , G11B5/012 , G11B19/04 , G11B21/10
摘要： An information storage apparatus having a disk medium 3 with data recording areas 203 along a plurality of tracks concentrically arranged, a head 4 for recording and reproducing data on tracks of the disk medium, an actuator 5 for moving the head to a desired track among the plurality of tracks, and an electric circuit 7 for controlling recording and reproducing and for detecting the distance from a recorded magnetization pattern on the adjacent tracks in the radial direction by detecting already recorded signals of adjacent tracks during data recording. By use of this constitution, even if the track density is increased, the upper limit of the threshold value setting range in the function for preventing from offtrack recording of the information storage apparatus can be increased and a high track density of the information storage apparatus can be easily realized.

4. 发明专利

JP2005004917A Vertical magnetic recording medium and magnetic disk unit 审中-公开
标题翻译：垂直磁记录介质和磁盘单元
公开(公告)号：JP2005004917A
公开(公告)日：2005-01-06
申请号：JP2003169261
申请日：2003-06-13
申请人： Hitachi Ltd , 株式会社日立製作所
发明人： HAMAGUCHI KATSUHIKO , MAEDA HIDEAKI , SHISHIDA KAZUHISA , NISHIDA YASUTAKA
IPC分类号： G11B5/82 , G11B5/596 , G11B21/10
CPC分类号： G11B5/59655
摘要： PROBLEM TO BE SOLVED: To provide a servo pattern stable over a long period of time, easy to be written, and excellent in S/N ratio.
SOLUTION: The sum total of the intensity of the magnetization of a burst part of the servo pattern is made 0 by forming a dc signal part involved in the burst part of the servo pattern with a combination of positive and negative dc signal components and low density dummy bits or a pattern shifted in its phase from the servo pattern.
COPYRIGHT: (C)2005,JPO&NCIPI
摘要翻译：要解决的问题：提供长时间稳定的伺服模式，易于写入，并且S / N比优异。解决方案：通过使用正和负直流信号分量的组合形成伺服模式的脉冲部分中涉及的直流信号部分，使伺服模式的脉冲部分的磁化强度的总和为0 和低密度虚拟位或在其相位上从伺服模式移位的模式。版权所有（C）2005，JPO＆NCIPI

5. 发明专利

JP2004171762A Method for manufacturing single magnetic pole magnetic head 审中-公开
公开(公告)号：JP2004171762A
公开(公告)日：2004-06-17
申请号：JP2004015111
申请日：2004-01-23
申请人： Hitachi Ltd , 株式会社日立製作所
发明人： OKADA TOSHIHIRO , KAWATO YOSHIAKI , NISHIDA YASUTAKA , WAKAGI YASUO
IPC分类号： G11B5/31
摘要： PROBLEM TO BE SOLVED: To manufacture a magnetic head for perpendicular recording in which there is no writing from the main magnetic pole side and no erasure between the adjacent tracks, and to obtain a magnetic disk device using the magnetic head. SOLUTION: The side of the main magnetic pole of the magnetic head for perpendicular recording is formed into an inverse tapered shape. The inverse tapered shape is obtained by previously forming a groove being a track part on an inorganic insulation film, then forming a magnetic film, and flatting the upper surface. COPYRIGHT: (C)2004,JPO

6. 发明专利

JP2001256605A MAGNETIC HEAD, MAGNETIC DISK DEVICE, AND INFORMATION RECORDING SYSTEM 失效
公开(公告)号：JP2001256605A
公开(公告)日：2001-09-21
申请号：JP2000076333
申请日：2000-03-14
申请人： HITACHI LTD
发明人： TOMIYAMA HIROSHI , HAMAGUCHI KATSUHIKO , HARA YOSHINORI , AKAGI FUMIKO , NISHIDA YASUTAKA
IPC分类号： G11B5/012 , G11B5/02 , G11B5/187 , G11B5/31 , G11B5/48
摘要： PROBLEM TO BE SOLVED: To provide a magnetic head, capable of preventing the acceleration of the heat softening of an adjacent track, even in the area of a large skew angle, and a magnetic disk device. SOLUTION: As a representative means, the shape of an upper magnetic pole is formed, in such a manner that in the maximum skew angle position, the maximum value of a slanting shadow length in disk radial direction is set equal to/lower than that of the track pitch.

7. 发明专利

JP2001243602A MAGNETIC RECORDING AND REPRODUCING DEVICE 失效
公开(公告)号：JP2001243602A
公开(公告)日：2001-09-07
申请号：JP2000051917
申请日：2000-02-28
申请人： HITACHI LTD , HITACHI METALS LTD
发明人： NISHIDA YASUTAKA , TAKANO KOJI , MOCHIZUKI MASABUMI
IPC分类号： G11B5/667 , G11B5/00 , G11B5/02 , G11B5/127 , G11B5/187 , G11B5/48 , G11B5/66 , G11B5/73 , G11B5/738
摘要： PROBLEM TO BE SOLVED: To make the backing magnetic layer thickness of a double-layer vertical magnetic recording medium thinner than in the conventional practice while avoiding saturation. SOLUTION: When the backing magnetic layer thickness of the double-layer vertical magnetic recording medium is defined as Tb1, its saturation magnetic flux density is defined as Bs2, magnetic pole thickness in the direction of a track in the vicinity of the floating surface of the main magnetic pole 1 of a magnetic recording head is defined as Tm, its track width is defined as Tww, and its saturation magnetic flux density is defined as Bs1, Tb1

8. 发明专利

JPH0950602A METHOD FOR DETECTING RECORDING CODE, CIRCUIT THEREFOR AND MAGNETIC RECORDING AND REPRODUCING DEVICE 失效
公开(公告)号：JPH0950602A
公开(公告)日：1997-02-18
申请号：JP19840795
申请日：1995-08-03
申请人： HITACHI LTD
发明人： NISHIDA YASUTAKA , UMEMOTO MASUO
IPC分类号： G11B5/09 , G11B20/10 , G11B20/14 , G11B20/18
摘要： PROBLEM TO BE SOLVED: To enhance accuracy in a simple circuit configuration by discriminating a likelihood based on same or different polarity of an amplitude value and an amplitude value difference between two bits in front and rear of a detecting object bit at the present point of time in a regenerative signal waveform of isolated magnetizing transition after specific equalization. SOLUTION: The regenerative signal waveform A of isolated magnetizing transition to be regenerated by a reproducing head reproducing codes recorded according to reverse/nonreverse of the magnetizing direction on a magnetic recording medium; is formed in a dipal state having a zero-cross point. The waveform A is equalized so as to make a standardization amplitude value at the detecting point of the equalized regenerative signal waveform B ...0, 1, 0, -1, 0... or ...0, -1, 0, 1, 0.... Then, same or different polarity of the amplitude value of the waveform B between two bits in front and rear of the detecting object bit at the present point of time is discriminated by a polarity discriminator 173, and a likelihood based on an amplitude value difference is discriminated by a likelihood discriminating part 174. Thus, the recorded codes on the medium can be detected with high accuracy by an MR head under diminished influence of nonlinearity in a simple circuit configuration.

9. 发明专利

JPH097300A EQUALIZER AND MAGNETIC RECORDING AND REPRODUCING DEVICE 失效
公开(公告)号：JPH097300A
公开(公告)日：1997-01-10
申请号：JP14981995
申请日：1995-06-16
申请人： HITACHI LTD
发明人： NISHIDA YASUTAKA , SAWAGUCHI HIDEKI
IPC分类号： G11B5/09 , G11B20/10
摘要： PURPOSE: To obtain an equalizer which can cancel different wave form distortion with simple circuit constitution even in the case in which a conventional linear signal processing system is used. CONSTITUTION: In an equalizer compensating waveform distortion in an input signal, this equalizer is provided with an amplitude value convertor 1 converting an input signal value to the other value by a Nth order function conversion characteristic (N>1), a non-circulation type filter 2 equalizing a waveform of an output of the amplitude value convertor 1, and a learning section which learns and updates a coefficient deciding characteristics of the amplitude value convertor 1 basing magnitude of an equalizing error of an output of the non- circulation type filter 2 as a judging reference so that the equalizing error is made the minimum and a tap coefficient of the non-circulation type filter 2.

10. 发明专利

JP2002092821A SINGLE MAGNETIC POLE TYPE MAGNETIC HEAD AND MAGNETIC DISK DEVICE MOUNTED WITH THE SAME 失效
公开(公告)号：JP2002092821A
公开(公告)日：2002-03-29
申请号：JP2000286842
申请日：2000-09-18
申请人： HITACHI LTD
发明人： OKADA TOSHIHIRO , KAWATO YOSHIAKI , NISHIDA YASUTAKA , WAKAGI YASUO
IPC分类号： G11B5/31
摘要： PROBLEM TO BE SOLVED: To manufacture a magnetic head for perpendicular recording without writing from a principal magnetic pole side surface and without erasing of an adjacent track and to provide a magnetic disk device using it. SOLUTION: The side surface of the principal magnetic pole of the magnetic head for perpendicular recording is formed in an inverse taper shape. The inverse taper shape is obtained by previously forming a groove to be a track part in an inorganic insulating film, then forming a magnetic film and flattening the upper surface thereof.

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