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141. 发明专利

JPH06124493A MAGNETO-OPTICAL DISK TRIAL RECORDING APPARATUS 失效
公开(公告)号：JPH06124493A
公开(公告)日：1994-05-06
申请号：JP27159292
申请日：1992-10-09
申请人： FUJITSU LTD
发明人： IZUMI HARUHIKO , TAGUCHI MASAKAZU , MORITSUGU MASAHARU
IPC分类号： G11B11/10 , G11B11/105
摘要： PURPOSE:To record a proper mark by a method wherein, when a mark is recorded on a magneto-optical disk, the trial decision of a recording compensa tion amount is executed to three edge-shift characteristics of a pattern shift, a thermal shift and a steady shift. CONSTITUTION:In a first multiplication part 21, a pattern-shift interpolating function x1 and pattern shift data Da are multiplied, the magnitude and the inclination of a pattern shift when a mark length is shortest and when it is longest are found, and they are output as interpolating pattern shift data Da1. The data Da1 is operated and processed in a pattern-shift compensation amount operation part 22, and a pattern-shift compensation signal Sa is formed. In a second multiplication part 24, a thermal-shift interpolating function x2 and thermal shift data Db are multiplied, the magnitude and the inclination of a thermal shift when a mark interval is shortest and when it is longest are found, and interpolating thermal shift data Sb is formed. In addition, a comparison and judgment part 27 compares steady shift data Dc with upper-limit and lower- limit reference values x3, x4 and judges them, and it outputs a light-emitting power change signal Sc for a mark recording laser beam according to the result of the judgment.

142. 发明专利

JPH05242543A 失效
公开(公告)号：JPH05242543A
公开(公告)日：1993-09-21
申请号：JP4487292
申请日：1992-03-02
申请人： FUJITSU LTD
发明人： MORITSUGU MASAHARU , IZUMI HARUHIKO , TAGUCHI MASAKAZU
IPC分类号： G11B11/10 , G11B11/105
摘要： PURPOSE:To prevent the generation of a transitional phenomenon when the reproduction of an optical magnetic area is started and to accurately reproduce recorded data by recording a pseudo optical magnetic signal having a pattern similar to user information on an identification area. CONSTITUTION:A pseudo optical magnetic signal from an optical magnetic signal pattern generation circuit 44 is taken out of an AND circuit 43 while scanning an ID area and supplied to a driving circuit 45. Thus, when information about an optical magnetic disk 15 recording the pseudo optical magnetic signal once on ID area is recorded and then reproduced, the transitional phenomenon is generated when the reproduction of the ID area is started. But since the pseudo optical magnetic signal is recorded on the ID area, the generation of the transitional phenomenon is prevented at the time of starting the reproduction of an MO area, a reproducing signal without a fluctuation at a DC level is gained, this reproducing signal is easily transformed into a pulse by slicing it at a reference level and thus, the recorded data is reproduced.

143. 发明专利

JPH05225634A MAGNETO-OPTICAL DISK REPRODUCTION SYSTEM 失效
公开(公告)号：JPH05225634A
公开(公告)日：1993-09-03
申请号：JP2294792
申请日：1992-02-07
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 prevent an increase in the reproduction error rate and to conduct a stable reproduction even though the length of recording marks is reduced in a magneto-optical disk reproduction system. CONSTITUTION:Edges of a magnetic domain in a magneto-optical disk are recorded with data coded so that a false value is always inserted between true values. The recorded data are detected and reproduced from reproduced waveforms of the magneto-optical disk having the edges recorded with the data in accordance with the true values of the data. Amplitude detection means (11 to 13) detect amplitude values of the reproduced waveforms. Decoding means (14 to 18) obtain the number of false values between the true values in accordance with the size of amplitude values detected and decode the recorded data.

144. 发明专利

JPH05225578A OPTICAL DISK DEVICE 失效
公开(公告)号：JPH05225578A
公开(公告)日：1993-09-03
申请号：JP17134591
申请日：1991-07-11
申请人： FUJITSU LTD
发明人： TAGUCHI MASAKAZU , MORITSUGU MASAHARU , IZUMI HARUHIKO
IPC分类号： G11B7/085 , G11B7/135
摘要： PURPOSE:To lighten a movable optical part and to perform access at high speed by disposing a raising mirror raising a laser beam so as to be incident on an optical disk perpendicularly on a position corresponding to the moving range of an optical part. CONSTITUTION:A motor 23 and an actuator 33 are driven by a drive control circuit 40 simultaneously and a galvanomirror 21 is rotated in the direction of the arrows B1, B2 and a movable optical part 6A is moved in the direction of the arrows C1, C2. When the incident point of a raising mirror 25 of a laser beam 29 outgoing from a laser unit device 24 to the reflecting sun-face 37 of the raising mirror 25 is regarded as Q, the movable optical part 6A is driven so as to position on right above of the incident point Q always. Thus, the laser beam 29 raised by the mirror 25 is incident on an objective lens 9 and converged on the optical disk 2.

145. 发明专利

JPH04360048A REPRODUCING METHOD AND DEVICE FOR OPTICAL MAGNETIC DISK 失效
公开(公告)号：JPH04360048A
公开(公告)日：1992-12-14
申请号：JP13640591
申请日：1991-06-07
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 make it possible to correct the position of an edge based on a detection result obtained by detecting a domain length (the dispersion of edge spacings) by a recording condition at the time of reproducing. CONSTITUTION:The recording of information is performed by irradiating an optical magnetic disk with light beam in accordance with recording data and forming a domain D column where the direction of magnetization is different on the above optical magnetic disk so that the spacings of the edge of the said domain D may correspond to '1' or '0' of recording data Dw. At the time of reproducing, recording data is read by detecting the spacing of the edge from a reproduction signal Sr. The expansion of the recorded domain D is decided based on a domain length decision signal obtained by integrating the reproduction signal Sr obtained from a VFO pull-in area Mv at the time of reproducing.

146. 发明专利

JPH04341927A MAGNETO-OPTICAL DISK SIGNAL REPRODUCING DEVICE 失效
公开(公告)号：JPH04341927A
公开(公告)日：1992-11-27
申请号：JP11279391
申请日：1991-05-17
申请人： FUJITSU LTD
发明人： MORITSUGU MASAHARU , IZUMI HARUHIKO , TAGUCHI MASAKAZU
IPC分类号： G11B7/00 , G11B7/005 , G11B11/10 , G11B11/105 , H03F3/08
摘要： PURPOSE:To provide a magneto-optical disk signal reproducing device which holds the ratio of the output currents of photodetectors to be inputted to a differential amplifier at a definite value and in addition, is provided with a control means capable of being made into an IC circuit. CONSTITUTION:The magneto-optical disk signal reproducing device which reproduces information by using the differential value of each photocurrent I1, I2 converted from each separated light by each photodetector 9a, 9b after separating the information recorded on a magneto-optical disk into orthogonal polarized light components is provided. In this device, current mirror circuits 11a, 11b which input the photocurrents I1, I2 as reference current, and output mirror currents i1, i2 corresponding to the reference current respectively, and mirror current control circuit 18 which controls the basic components of the mirror currents i1, i2 so as to be the same value are provided, and the device is constituted so as to use the above-mentioned mirror currents i1, i2 instead of the photocurrents I1, I2.

147. 发明专利

JPH04310649A EDGE RECORDING AND REPRODUCING SYSTEM FOR PHOTOELECTRO-MAGNETIC DISK DEVICE 失效
公开(公告)号：JPH04310649A
公开(公告)日：1992-11-02
申请号：JP7626291
申请日：1991-04-09
申请人： FUJITSU LTD
发明人： IZUMI HARUHIKO , MORITSUGU MASAHARU , TAGUCHI MASAKAZU
IPC分类号： G11B7/00 , G11B7/0045 , G11B7/005 , G11B11/10 , G11B11/105
摘要： PURPOSE:To lessen the influence of the edge dislocation of a recording domain due to heat interference by forming recording domain length so that the constant quantity of the length can be short. CONSTITUTION:The recording domain column is formed so as to make the length of the recording domain shorter than the interval of recording data only by the constant quantity at the time of recording. For example, the recording domain having an edge dislocated later than the edge of the inherent recording domain by the constant quantity is formed so that the rise timing of a recording optical beam can be later only by the constant quantity for the timing of the recording data. Thus, the interval of the adjoining recording domain is wider than the interval of the inherent recording domain, the influence of the heat interference is lessened and the edge dislocation can be reduced in recording. The quantity to cancel the dislocation of an edge detecting position to occur at the time of reproduction is dislocated by making short the length of the recording domain at the time of recording from the middle point of the reproduction waveform for the slice level at the time of reproduction. Thus, regardless of the fact that the length of the recording domain is formed shorter than the inherent length, the correct reproducing signal can be obtained.

148. 发明专利

JPH04291041A MAGNETO-OPTICAL DISK REPRODUCING SYSTEM 失效
公开(公告)号：JPH04291041A
公开(公告)日：1992-10-15
申请号：JP5732891
申请日：1991-03-20
申请人： FUJITSU LTD
发明人： TAGUCHI MASAKAZU , NIMATA AKIO , MORITSUGU MASAHARU , IZUMI HARUHIKO
IPC分类号： G11B11/10 , G11B11/105 , G11B20/14
摘要： PURPOSE:To perform reproducing without being affected by the change of temperature, dispersion between media and difference in the shape between magnetic section front and rear ends, etc., and to minimize the scale of a circuit. CONSTITUTION:An edge detection means 31 detects the edge of the front and rear ends, respectively, of each magnetic section from a reproducing signal. Counting means 33 and 34 counts the time difference between the edge detection signal of the rear (or front) end and that of the front (or rear) end. A phase shift means 32 and 37 shifts the edge detection signal of the front (or rear) end corresponding to the counted value of the counting means. A synthesizing means 35 synthesizes the edge detection signal of the rear (or front) end with the phase-shifted edge detection signal of the front (or rear) end. Extraction means 36 and 38 extracts a clock and data from the synthesized signal.

149. 发明专利

JPH04291040A DATA RECORDING SYSTEM FOR MAGNETO-OPTICAL DISK DEVICE 失效
公开(公告)号：JPH04291040A
公开(公告)日：1992-10-15
申请号：JP5732691
申请日：1991-03-20
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 easily execute high density recording by keeping the power of a light beam of a true value part at a level which does not change the magnetizing direction of an magneto-optical disk and maintaining the preliminarily specified magnetizing direction. CONSTITUTION:In the data recording method of an magneto-optical disk device which records data encoded so that a false value is securely inserted between true values, a recording domain is applied to the disk 1 in the magnetizing direction of a coil 3 which is reversal to that in the case of deletion and at the same time, the light beam is applied from an optical head 4 to the disk 1 with enough power to magnetize the domain in the magnetic field direction by the coil 3 to form the domain to the false value part. The true value part is set to a position where the recording domain is not formed. Thus, the intervals between the recording domains can be set small and thus, the data recording at high density can be obtained.

150. 发明专利

JPH04283438A SIGNAL REPRODUCING METHOD AND DEVICE FOR MAGNETO OPTICAL DISK 失效
公开(公告)号：JPH04283438A
公开(公告)日：1992-10-08
申请号：JP4651091
申请日：1991-03-12
申请人： FUJITSU LTD
发明人： MORITSUGU MASAHARU , IZUMI HARUHIKO , TAGUCHI MASAKAZU
IPC分类号： G11B11/10 , G11B11/105
摘要： PURPOSE:To operate a correction and emphasis, and to prevent a bit string demodulated by the regenerative signal of a recorded mark from being unmatched with a recorded bit string by adding a positive differential signal corresponding to the rising side of the regenerative signal to the regenerative signal. CONSTITUTION:When a regenerated signal S0 is differentiated by a differentiator 15, a differential signal Sd is turned to be positive at the time of the rising of the regenerated signal S0, and turned to be negative at the time of the falling of the regenerated signal S0. A positive differential signal Sd1 at the time of the rising of the regenerated signal S0 is necessitated at that time. Then, a negative differential signal Sd2 at the time of the falling of the regenerated signal S0 is cut off by a rectifier 16, and the positive differential signal Sd1 is added to the regenerated signal S0 by an adder 20, so that a corrected regenerative signal S1 obtained by emphasizing and correcting the rising of the regenerated signal S0 which is weakened by a teardrop mark can be obtained. Thus, the bit string(data) demodulated by the regenerated signal can be prevented from being unmatched with the recorded bit string(data).

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