公开(公告)号：DE2735319A1

公开(公告)日：1978-03-09

申请号：DE2735319

申请日：1977-08-05

Applicant: IBM

Inventor： ARNOLD RICHARD FAIRBANKS ,  DISHON YITZHAK ,  OUCHI NORMAN KEN ,  SCHOR MARSHALL I

IPC: H03M7/40 ,  H03M7/42 ,  H04L23/00 ,  G06F5/00

Abstract: In an apparatus for generating variable length codewords c(ai) and c(aj) responsive to corresponding fixed length codewords b(ai) and b(aj), where ai and aj are source alphabet characters, ai epsilon A1 and aj epsilon A2, ambiguity arises whenever any fixed length character to be encoded can instantaneously represent source characters ai and aj drawn from two or more dissimilar alphabets i.e. A1 or A2. This is resolved by the inclusion of a Markov processor in combination with the apparatus. The processor establishes the point in the sequence when transitions occur between fixed length characters in one alphabet to fixed length characters in another alphabet by the message context. The processor includes a map of state and transition paths. This map models certain statistical regularities of runs of fixed code elements and the relative likelihood that an ambiguous fixed code character appearing in a first run belongs to a given alphabet. The processor, starting from an arbitrary initial position, tracks any given run of fixed code characters applied to the encoder in terms of a succession of states and paths.

公开(公告)号：DE2540472A1

公开(公告)日：1976-05-06

申请号：DE2540472

申请日：1975-09-11

Applicant: IBM

Inventor： OUCHI NORMAN KEN

IPC: H03M5/14 ,  G06T9/00 ,  G11B20/14 ,  H03M7/14 ,  H03M7/30 ,  H03M7/40 ,  H04L23/00 ,  H04L25/49 ,  H03K13/00 ,  G06F5/00

Abstract: An apparatus for processing data employs a modification of a zero modulation code. The zero modulation code has a waveform that is symmetrical about a zero signal level within narrow defined limits. Each data digit, 1 or 0, is encoded into two NRZI digits. A relaxed run length limitation allows use of a (d,k) code of (1,4), where (d) is the minimum number of 0 digits between 1 digits and (k) is the maximum number of 0 digits between 1 digits, without violating the frequency and charge constraints. Only five charge states and only one bit lookahead is needed in order to encode data in the (1,4) code.

公开(公告)号：DE3750380T2

公开(公告)日：1995-03-30

申请号：DE3750380

申请日：1987-05-05

Applicant: IBM

Inventor： NG CHAN YIU ,  OUCHI NORMAN KEN ,  WANG DAVID TAR-WEI ,  YU WELLINGTON CHIA-PEIR

IPC: G11B20/12 ,  G11B27/30

Abstract: A record that emulates a first recording format, which includes a track reference point, such as an index field, used for determining a position of a record on a track according to the first recording format, is recorded on a moving storage device operating according to a second recording format which also includes a track reference point by the following method. The method comprises the steps, responsive to location information generated according to the first recording format, of: (1) determining an original angular position of a record according to the first recording format; (2) calculating in response to the original angular position and a parameter a preferred angular position for the record according to the second recording format; (3) determining an actual angular position of the record recorded according to the second recording format; and (4) recording an extension of the record to compensate for the difference between the preferred angular position and the actual angular position. h

公开(公告)号：DE3750380D1

公开(公告)日：1994-09-22

申请号：DE3750380

申请日：1987-05-05

Applicant: IBM

Inventor： NG CHAN YIU ,  OUCHI NORMAN KEN ,  WANG DAVID TAR-WEI ,  YU WELLINGTON CHIA-PEIR

IPC: G11B20/12 ,  G11B27/30

Abstract: A record that emulates a first recording format, which includes a track reference point, such as an index field, used for determining a position of a record on a track according to the first recording format, is recorded on a moving storage device operating according to a second recording format which also includes a track reference point by the following method. The method comprises the steps, responsive to location information generated according to the first recording format, of: (1) determining an original angular position of a record according to the first recording format; (2) calculating in response to the original angular position and a parameter a preferred angular position for the record according to the second recording format; (3) determining an actual angular position of the record recorded according to the second recording format; and (4) recording an extension of the record to compensate for the difference between the preferred angular position and the actual angular position. h

公开(公告)号：AU2814177A

公开(公告)日：1979-03-08

申请号：AU2814177

申请日：1977-08-23

Applicant: IBM

Inventor： ARNOLD RICHARD FAIRBANKS ,  DISHON YITZHAK ,  OUCHI NORMAN KEN ,  SCHOR MARSHALL I

IPC: H03M7/40 ,  H03M7/42 ,  H04L23/00 ,  H04L3/00 ,  G06F15/38 ,  H03K13/24

Abstract: In an apparatus for generating variable length codewords c(ai) and c(aj) responsive to corresponding fixed length codewords b(ai) and b(aj), where ai and aj are source alphabet characters, ai epsilon A1 and aj epsilon A2, ambiguity arises whenever any fixed length character to be encoded can instantaneously represent source characters ai and aj drawn from two or more dissimilar alphabets i.e. A1 or A2. This is resolved by the inclusion of a Markov processor in combination with the apparatus. The processor establishes the point in the sequence when transitions occur between fixed length characters in one alphabet to fixed length characters in another alphabet by the message context. The processor includes a map of state and transition paths. This map models certain statistical regularities of runs of fixed code elements and the relative likelihood that an ambiguous fixed code character appearing in a first run belongs to a given alphabet. The processor, starting from an arbitrary initial position, tracks any given run of fixed code characters applied to the encoder in terms of a succession of states and paths.