Patents Assigned to Elcomatic Limited
  • Modified frequency modulation
    Patent number: 4376958
    Abstract: There is described methods and circuitry for decoding modified frequency modulated (MFM) information signals as obtained from rotating magnetic storage devices, such as floppy disks and hard disks used in computers. The novel technique involves twice squaring an information carrying data signal mathematically and without saturation, deriving a clock signal from the twice squared data signal using a phase lock loop and thereafter recovering an information signal from said data signal and clock signal.
    Type: Grant
    Filed: July 8, 1980
    Date of Patent: March 15, 1983
    Assignee: Elcomatic Limited
    Inventor: Archibald M. Pettigrew