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1. 发明专利

JPH07210995A OPTICAL DISK DEVICE 失效
公开(公告)号：JPH07210995A
公开(公告)日：1995-08-11
申请号：JP8794
申请日：1994-01-05
申请人： FUJITSU LTD
发明人： MORITSUGU MASAHARU , TANAKA SHIGEYOSHI
IPC分类号： G11B20/10
摘要： PURPOSE:To accurately read data even when resolution is degraded due to increasing integration density or variation of recording conditions, or even when variation of transient and an envelope exist. CONSTITUTION:A clamp circuit 104 clamps a peak of a reproduced signal RDS, an amplitude comparing section 108 compares amplitude of a clamp signal outputted from the clamp circuit 104 with the reference voltage, an AGC control section 102 generates a control voltage signal Vcnt in accordance with a difference of amplitude and controls gain of a gain variable amplifier 101. A gate signal generating section 105 compares a clamp signal CLP outputted from the clamp circuit 104 with the prescribed signal and generates a gate signal GTS, a data pulse outputting section 107 outputs a data pulse DT when a differential zero cross signal ZCS of a reproduced signal is generated at the time of generation of the gate signal GTS.

2. 发明专利

JPH05334754A 失效
公开(公告)号：JPH05334754A
公开(公告)日：1993-12-17
申请号：JP13912892
申请日：1992-05-29
申请人： FUJITSU LTD
发明人： IZUMI HARUHIKO , MORITSUGU MASAHARU , TAGUCHI MASAKAZU
IPC分类号： G11B7/00 , G11B7/005 , G11B11/10 , G11B11/105 , G11B20/10 , G11B20/14
摘要： PURPOSE:To accurately detect data even when an amplitude change occurs in a regenerative signal waveform according to a data pattern in a magneto- optical disk reproducing device reproducing the recorded information of a magneto-optical disk on which the information is recorded by an edge recording system. CONSTITUTION:A leading and a trailing edges are detected by an edge detection circuit 33 from a regenerative waveform and a leading edge pulse and a trailing edge pulse are formed and a synchronous clock is picked up from the leading pulse by a PLL constituted of a phase comparator circuit 40, an LPF 41 and a VCCO 42. Further, by the phase comparator circuit 43, a phase difference between the trailing pulse and the synchronous clock is detected and a delay amt. in a variable delay circuit 38 is changed based on the phase difference and the phase of the trailing pulse corrected. Then, the leading pulse and the trailing pulse and synthesized by a synthesis circuit 39 and by a data discriminating circuit 45, a data signal is regenerated by using the synchronous clock.

3. 发明专利

JPH0578094B2 失效
公开(公告)号：JPH0578094B2
公开(公告)日：1993-10-28
申请号：JP24075783
申请日：1983-12-19
申请人： FUJITSU LTD
发明人： NIMATA AKIO , MINAMI AKIRA , OKADA SHINJI , MORITSUGU MASAHARU
IPC分类号： G11B7/00 , G11B7/0045 , G11B7/085 , G11B7/09 , G11B7/125

4. 发明专利

JPH05197957A RECORD COMPENSATION SYSTEM FOR OPTICAL DISK 失效
公开(公告)号：JPH05197957A
公开(公告)日：1993-08-06
申请号：JP778092
申请日：1992-01-20
申请人： FUJITSU LTD
发明人： MORITSUGU MASAHARU , IZUMI HARUHIKO , TAGUCHI MASAKAZU
IPC分类号： G11B7/00 , G11B7/0045 , G11B7/125
摘要： PURPOSE:To compensate a record so that a pattern shift quantity and a thermal shift quantity become constant regardless of a recording data pattern. CONSTITUTION:The pulse width of a recording pulse is measured by a pulse width measuring means 1. The more the fall of the recording pulse is quickened the more the measured pulse width is larger by a fall control means 2. The pulse interval of the recording pulse is measured by a pulse interval measuring means 4. The more the rise of next recording pulse is delayed the more the measured pulse interval is smaller by a rise control means 5.

5. 发明专利

JPH05144008A REPRODUCTION METHOD AND CIRCUIT OF MARK LENGTH RECORDING SYSTEM 失效
公开(公告)号：JPH05144008A
公开(公告)日：1993-06-11
申请号：JP30753591
申请日：1991-11-22
申请人： FUJITSU LTD
发明人： IZUMI HARUHIKO , MORITSUGU MASAHARU , TAGUCHI MASAKAZU
IPC分类号： G11B7/00 , G11B7/005 , G11B11/10 , G11B11/105
摘要： PURPOSE:To prevent a positional deviation caused by a jitter by subtracting a double differentiated signal of reproduced signal from the reproduced signal so as to steepen rise of the reproduced signals. CONSTITUTION:On a magneto-optical disk, a bit train is formed so that the distance between data 1s becomes the distance between edges of mark edges of mark length recording pits. This pit train is irradiated with reproduction spot beams and the position of an edge is detected. The reproduced waveform is made to the double differentiated signal T by a second order HPF 11 resulting in positive and negative peaks Ta and Tb corresponding to the start and the end of a rise of a reproduced signal Sa, a peak To corresponding to the peak of the signal Sa and negative and positive peaks Tc and Td corresponding to the start and the end of a fall of the reproduced signal Sa following the peak, respectively. Therefore, the rise and the fall of the composite waveform, which is made by subtracting the double differentiated signal of the reproduced waveform through a proper gain amplifier 12 at a subtracting circuit 13, are emphasized, the rise of the reproduced signal becomes steeper and positional deviations due to jitters are prevented.

6. 发明专利

JPH05114188A MAGNETO-OPTICAL DISK REPRODUCING DEVICE 失效
公开(公告)号：JPH05114188A
公开(公告)日：1993-05-07
申请号：JP27571291
申请日：1991-10-23
申请人： FUJITSU LTD
发明人： TAGUCHI MASAKAZU , MORITSUGU MASAHARU , IZUMI HARUHIKO
IPC分类号： G11B7/00 , G11B7/005 , G11B11/10 , G11B11/105
摘要： PURPOSE:To correct an influence of the change of the edge interval to perform reproducing with a small number of delay lines however changed the edge intervals is by using a peak value to calculate the extent of correction and correcting the edge position based on the calculation result. CONSTITUTION:The reproduced signal obtained from a reproducing means 18 is supplied to an edge detecting means 20, a peak detecting means 21, and a bottom detecting means 22. Edges are detected from the reproduced signal by the means 20, and the leading edge signal and the trailing edge signal of a recording bit are individually detected. The reproduced signal is sent to means 21, 22 to successively hold the peak value and the bottom value of the reproduced signal. A first arithmetic means 23 performs the operation based on the peak value of the reproduced signal obtained by the means 21 and sends the operation result to a first correcting means 25 to correct the trailing edge reproduced pulse. The operation is performed based on the peak value and the bottom value, and the operation result is supplied to a second correcting means 26 to correct the leading edge reproduced pulse. Thus, edges are reproduced without an influence of the recording temperature or the magnetic domain form.

7. 发明专利

JPH0512833A DISK DEVICE 失效
公开(公告)号：JPH0512833A
公开(公告)日：1993-01-22
申请号：JP16050091
申请日：1991-07-01
申请人： FUJITSU LTD
发明人： TAGUCHI MASAKAZU , MORITSUGU MASAHARU , FUKUSHIMA NOBUHIRO
IPC分类号： G11B7/08 , G11B25/04
摘要： PURPOSE:To make the device thin by providing a rotating center axis of a disk inclined with an undermined angle from a vertical line against a chassis. CONSTITUTION:The rotating center axis 3 of a disk 2 is made to inclin at an angle theta to a vertical axis 21 against a chassis 4. An upper side head 5 is arranged on the part of the lower side of the disk 2 and a lower side head 6 is arranged on the part of the upper side of the disk 2. Thus, the thickness of a space occupied by the disk 2. The first head 5 and the second head 6 on the chassis 4 is made parallel to the chassis, thinner than the existing constitution where the first and second heads are arranged putting the disk between them and the disk device is made thin.

8. 发明专利

JPH04355236A RECORDING METHOD AND DEVICE FOR MAGNETO-OPTICAL DISK 失效
公开(公告)号：JPH04355236A
公开(公告)日：1992-12-09
申请号：JP12922091
申请日：1991-05-31
申请人： FUJITSU LTD
发明人： IZUMI HARUHIKO , MORITSUGU MASAHARU , TAGUCHI MASAKAZU
IPC分类号： G11B11/10 , G11B11/105
摘要： PURPOSE:To provide the recording method and device for magnetooptical disks which can execute exact recording in the position where the edges of domains correspond to '1' of recording data and can, therefore, obtain exact reproduced data. CONSTITUTION:The recording method for magneto-optical disks which forms the arrays of the domains D varying in the direction of magnetization from the circumference by heating with irradiation of the magneto-optical disk 20 having a vertical magnetized film with a recording beam and the impression of an external magnetic field and records the data on this magneto-optical disk 20 is so constituted as to execute the recording while the recording beam is deflected and vibrated at the frequency higher than the max. frequency component of the recording data in the radial direction of the magneto-optical disk 20. A deflection means 30, such as acoustooptical element, is used as the above- mentioned means for deflection and vibration. The rectangular domains D are formed in this way and the rise of the reproduced signals is steepened.

9. 发明专利

JPH04283426A OPTICAL RECORDING AND REPRODUCING DEVICE 失效
公开(公告)号：JPH04283426A
公开(公告)日：1992-10-08
申请号：JP4829891
申请日：1991-03-13
申请人： FUJITSU LTD
发明人： MORITSUGU MASAHARU , IZUMI HARUHIKO , TAGUCHI MASAKAZU
IPC分类号： G11B7/00 , G11B7/004 , G11B19/12
摘要： PURPOSE:To reproduce both ISO and CD specified optical disks by providing a switching means which turns ON the power source of a high frequency amplifier at the time of mounting the ISO specified optical disk, and turning OFF the power source of the high speed amplifier at the time of mounting the CD specified optical disk. CONSTITUTION:When a disk discriminating means 51 judges that the CD specified optical disk is mounted, a switch SWO is turned OFF by a switching signal S50. Thus the input impedance of a high frequency amplifier 10 is made high, and entire currents from a photodetector 11 pass through a direct current amplifier 20. A signal inputted to the direct current amplifier 20 is amplified, and inputted to both an information signal processing circuit 30 and a servo signal detecting circuit 40 at the next stage. When the above mentioned disk discriminating means 51 judges that the ISO specified optical disk is mounted, the switch SWO is turned ON, a high frequency component Ir of the outputs of the photodetector 11 is amplified through a capacitor Ci by the high frequency amplifier 10 outputted and used for an information reproduction signal S10.

10. 发明专利

JPH03286431A SEPARATE TYPE OPTICAL HEAD FOR OPTICAL DISK DEVICE 失效
公开(公告)号：JPH03286431A
公开(公告)日：1991-12-17
申请号：JP8774090
申请日：1990-04-02
申请人： FUJITSU LTD
发明人： MORITSUGU MASAHARU , IZUMI HARUHIKO
IPC分类号： G11B7/095 , G11B7/135
摘要： PURPOSE:To make a fixed part thin by fixing a jumping mirror which reflects laser light from the fixed part provided with a galvano-mirror so as to be made incident on an objective lens in a specified direction. CONSTITUTION:When the optical axis of the laser light going toward a movable part 42 from the fixed part 41 is made Z-axis, and the axes in the horizontal and vertical directions in a plane perpendicular to the Z-axis are made X-axis and Y-axis respectively, the device is constituted so that the laser light going toward the movable part 42 is swung in X-Z-plane. Then, when the X-axis, the Y-axis and the X-axis direction components of the normal vector of the reflecting plane of the jumping mirror 44 are made ix, jy, kz respectively, the jumping mirror 44 is set in the direction in which iy=kz, and in addition, ixnot equal to 0. Thus, the direction of the movement of a spot on an optical disk 9 becomes the direction having the component to cross a track, and the fixed part can be made thin.

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