Patents by Inventor Norman Durkee

Norman Durkee 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).

  • System for carrying transparent digital data within an audio signal
    Patent number: 5612943
    Abstract: A signal processing system comprises inputs for an analog audio signal and a digital data signal. The digital data signal is modulated to an analog data signal in an inaudible frequency band. Filters are used to ensure that the audio signal is restricted to audible frequencies and that the analog data signal is restricted to inaudible frequencies. The two analog signals are then combined into a composite analog signal. The composite signal is stored on a medium such as a compact disc. Filters are used to extract and separate the two analog signals from the composite signal stored on the medium. The analog data signal is demodulated to retrieve the original digital data signal.
    Type: Grant
    Filed: July 5, 1994
    Date of Patent: March 18, 1997
    Inventors: Robert W. Moses, Norman Durkee, Charles H. Hustig