Patents Assigned to Laserdrive Limited
  • Patent number: 4928187
    Abstract: An apparatus for encoding and decoding binary data in a data transmission system, such as a magnetic or optical medium data storage system is disclosed. The encoding process uses a modulation code wherein each data bit is encoded into a predetermined one of five code words, each code word including three code bits, such that 2, 4, 6, or 8 "0" code bits are generated between each "1" code bit. A "1" code bit signifies a signal transition and a "0" code bit signifies no signal transition. In the process of decoding, each series of three code bits, defined with respect to a detected synchronization signal, are decoded using the inverse of the encoding process to convert the code bits back into data bits. The synchronization pattern generated during the encoding process includes at least ten successive "0" bits.
    Type: Grant
    Filed: February 20, 1987
    Date of Patent: May 22, 1990
    Assignee: Laserdrive Limited
    Inventor: Theodore D. Rees
  • Patent number: 4908816
    Abstract: A linear motor with uniform force constant across the full stroke length achieved by varying the width of the air gap face area of the permanent magnet such that the width is reduced towards the center of the magnet in relation to the widths at the ends thereof to compensate for reducing field strength at the magnet ends caused by fringing effects on the field.
    Type: Grant
    Filed: December 20, 1988
    Date of Patent: March 13, 1990
    Assignee: Laserdrive Limited
    Inventors: Patrick J. Champagne, John L. Grimsley