Patents by Inventor John S. Fawkes

John S. Fawkes 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).

  • Circuit and method for generating a ramp signal
    Patent number: 4503396
    Abstract: Circuit and method for generating a ramp signal having an incrementally changing slope. The invention is particularly useful for ramping magnetic recording bias or erase signals by providing a relatively slow slope within the non-linear region of the magnetic medium characteristic while providing a relatively steep slope in the linear region to reduce recording of disturbing "pop" signals.
    Type: Grant
    Filed: April 2, 1982
    Date of Patent: March 5, 1985
    Assignee: Ampex Corporation
    Inventor: John S. Fawkes
  • Constant current biased head driver
    Patent number: 4480275
    Abstract: A constant current source is combined with a fixed AC bias circuit to supply a constant current biased drive signal to a control track, an audio, etc., record head. A voltage doubler bridge configuration may be used to double the current to the head.
    Type: Grant
    Filed: April 2, 1982
    Date of Patent: October 30, 1984
    Assignee: Ampex Corporation
    Inventor: John S. Fawkes
  • D.C. Controlled adjustable ramp signal generator and method
    Patent number: 4438466
    Abstract: Circuit and method for providing a D.C. controlled adjustable ramp signal which maintains a predetermined ramping period for respectively adjusted optimum signal levels within the operating range. An example of a circuit of the invention is described for providing an automatically controlled bias or erase ramp signal in a magnetic recorder.
    Type: Grant
    Filed: April 2, 1982
    Date of Patent: March 20, 1984
    Assignee: Ampex Corporation
    Inventors: John S. Fawkes, Walter F. Umholtz
  • Electronic switching circuit for use in magnetic head drives
    Patent number: 4428008
    Abstract: An electronic switching circuit coupled between a magnetic head driving circuit and transducing windings utilizing an electronic switch whose internal resistance changes substantially linearly in response to an increasing or decreasing control signal. Particularly useful in magnetic bias recording or erase circuits to eliminate erase of useful information and recording of disturbing noise spikes due to induced high frequency noise signal when the switch is activated.
    Type: Grant
    Filed: April 2, 1982
    Date of Patent: January 24, 1984
    Assignee: Ampex Corporation
    Inventor: John S. Fawkes