Patents by Inventor Francis S. Humphrey

Francis S. Humphrey 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).

  • Automatic volume control system
    Patent number: 4306115
    Abstract: An automatic volume control system comprises a source for producing an audio signal; an amplifier responsive to a control signal for varying the amplitude of the audio signal, a transducer for converting the audio signal to sound energy, a detector for detecting the output of the transducer and ambient noise which interferes with comprehension of the sound energy, and a phase comparator connected to the detector and to the audio signal source for comparing the phases of the outputs thereof and for producing an output proportional to the level of detected ambient noise. The output of the phase comparator is connected as a control signal to the amplifier means so as to control the amplitude of the audio signal.
    Type: Grant
    Filed: March 19, 1980
    Date of Patent: December 15, 1981
    Inventor: Francis S. Humphrey