Patents by Inventor Archibald M. Pettigrew

Archibald M. Pettigrew has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Amplitude locked loop circuits
    Patent number: 5341106
    Abstract: There is described an electronic circuit which operates an Amplitude Locked Loop. The circuit comprises a voltage controlled amplifier, a modulus detector and an integrator combined in a feedback loop. An FM signal decoder is also described as are a number of applications of Amplitude Locked Loop.
    Type: Grant
    Filed: July 22, 1992
    Date of Patent: August 23, 1994
    Assignee: The Governors of Paisley College of Technology
    Inventor: Archibald M. Pettigrew
  • Digital magnetic recording
    Patent number: 4499508
    Abstract: In a system for retrieving data from a recording medium employing MFM or FM encoding forms, a decoding method and circuit employs the technique of delaying the third harmonic of the data signal relative to the fundamental of the data signal by 180 degrees. This delaying is effected by the use of two resonant networks each delaying the third harmonic relative to the fundamental by 90 degrees. The delaying technique enables a differentation stage to be eliminated.
    Type: Grant
    Filed: February 18, 1982
    Date of Patent: February 12, 1985
    Inventor: Archibald M. Pettigrew
  • 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
  • Cross-coupled servo control mechanism for reel-to-reel tape drives
    Patent number: 4370683
    Abstract: The tape transport mechanism, in a tape drive for retrievable informational data storage, is provided with a cross-coupled tape speed control servomechanism, achieving controlled bidirectional movement and stopping of tape, without switching, and requiring only one polarity of power source for the motive elements.
    Type: Grant
    Filed: November 5, 1979
    Date of Patent: January 25, 1983
    Assignee: Burroughs Corporation
    Inventors: George H. Greig, Archibald M. Pettigrew