公开(公告)号：JP2000013236A

公开(公告)日：2000-01-14

申请号：JP17499898

申请日：1998-06-22

Applicant: SONY CORP

Inventor： NODA MAKOTO

IPC: H03M7/14

Abstract: PROBLEM TO BE SOLVED: To simplify a coding/decoding device and to increase number of generated code words in the code conversion method for a fixed length conversion code for non-return to zero inverted(NRZI) modulation where the maximum consecutive number of both bit information 0 and bit information 1 in a code series is limited. SOLUTION: In this code conversion method for a fixed length conversion code for NRZI modulation where the maximum consecutive number of both 0s and 1s in a code series is limited. The maximum consecutive number for both the 0s and 1s in the code series is set equal and a half of the conversion code words is configured through 0-1 conversion of the remaining half of the conversion code words to reduce at least the number of the conversion code words substantially required to a half thereby configuring the coding and decoding device with a very simple configuration and also maximizing number of code words that can be generated when a binding condition of the maximum consecutive number of 0s and 1s (sum of them) is made constant.

公开(公告)号：JPH11186917A

公开(公告)日：1999-07-09

申请号：JP34764997

申请日：1997-12-17

Applicant: SONY CORP

Inventor： NODA MAKOTO

IPC: G06F11/10 ,  G11B20/14 ,  G11B20/18 ,  H03M13/23 ,  H04L25/08 ,  H03M13/12

Abstract: PROBLEM TO BE SOLVED: To allow a method to obtain a matched spectral null type trellis code exempted from a quasi-destructive code where a high code generating efficiency and a simplified configuration of decoder are attained. SOLUTION: A matched spectral null type trellis code that is generated by a time changing trellis line diagram, which eliminates a quasi-destructive code series by deleting part of paths on a trellis line diagram is coded by combining two kinds of code series (codes A, B) the state number of which, tacking a code polarity of a start point and an end point of the code into account, is respectively 2. Since the code generating efficiency is improved by the coding method, a code with high coding rate is generated. Thus, the method contributes to enhanced recording line density in a recording and reproducing device in, e.g. a magnetic recording system. Furthermore, the configuration of a decoder is made comparatively simple.

公开(公告)号：JPH05135355A

公开(公告)日：1993-06-01

申请号：JP32509791

申请日：1991-11-14

Applicant: SONY CORP

Inventor： NODA MAKOTO

IPC: G11B5/716 ,  C09D5/23 ,  G11B5/73

Abstract: PURPOSE:To provide a magnetic recording medium to extremely improve reproduction output for copying at a short wavelength range and long wavelength range. CONSTITUTION:This magnetic recording medium is pressed with a recorded magnetic recording medium, bias electric field for copy is impressed at the condition and a recording signal of the recorded magnetic recording medium is copied. On a non-magnetic supporting body of the magnetic recording medium, a magnetic layer essentially consisting of a magnetic powder and a binder is formed at two layers, a coercive force(Hc1) of the magnetic powder mainly used in upper layer part of the above magnetic layer is 30-70KA/m, and a ratio of coercive force (HC2) of the magnetic powder mainly used in under part of the above magnetic layer to the above Hc1 (Hc2/Hc1) is 0.25-0.80.

公开(公告)号：JPH0261824A

公开(公告)日：1990-03-01

申请号：JP21243988

申请日：1988-08-29

Applicant: SONY CORP

Inventor： NODA MAKOTO ,  OKAZAKI YUTAKA

IPC: G11B5/706 ,  C09D5/23 ,  C09D127/04 ,  C09D127/06 ,  C09D175/00 ,  C09D175/04 ,  G11B5/86

Abstract: PURPOSE:To obtain excellent reproduction output particularly in a short wavelength region by specifying the saturated magnetic flux density of a magnetic layer to a specified Gausses or less in the magnetic recording medium in which signals are recorded by a magnetic field transfer system. CONSTITUTION:The magnetic recording medium is composed of a nonmagnetic supporting substance and the magnetic layer formed thereon comprising hexagonal ferrite magnetic powder and a binder, in which signals are recorded by a magnetic field transfer system. The saturated magnetic flux density of the magnetic layer is specified to

公开(公告)号：JPS63268124A

公开(公告)日：1988-11-04

申请号：JP10280887

申请日：1987-04-25

Applicant: SONY CORP

Inventor： OKAZAKI YUTAKA ,  NODA MAKOTO

IPC: G11B5/706 ,  C09D5/23 ,  C09D7/12 ,  G11B5/86

Abstract: PURPOSE:To improve transfer efficiency in a short wavelength region below a specific wavelength by specifying the squareness ratio in the perpendicular direction of a magnetic recording medium at a specific value or above, the coercive force in the perpendicular direction at a prescribed value or below and the surface roughness of a magnetic layer at a specified value or below. CONSTITUTION:The squareness ratio in the perpendicular direction of the magnetic medium for slave by a magnetic field transfer method which is formed with the magnetic layer essentially consisting of hexagonal ferrite magnetic powder and binder on a nonmagnetic base is specified at >=0.7, the coercive force Hc in the perpendicular direction at