Patents by Inventor Kaoru Izawa

Kaoru Izawa 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).

  • Echo attaching circuit and audio device using the same
    Patent number: 5444785
    Abstract: An analog signal to be delayed thereby is compressed according to a monotonously increasing, convex compression function and sent to a delay circuit constituted digitally. Data of a digital value stored in a memory is read out after a constant delay time and converted into an analog signal by a D/A converter. The analog signal is expanded according to a reverse function of the compression function to restore it as an echo signal.
    Type: Grant
    Filed: November 21, 1994
    Date of Patent: August 22, 1995
    Assignee: Rohm Co., Ltd.
    Inventors: Kaoru Izawa, Shigeyoshi Hayashi, Jun Hirai
  • Echo attaching circuit and audio device using the same
    Patent number: 5394474
    Abstract: This invention includes a compression circuit for compress one of an audio signal and a mixture of the audio signal and an echo signal, a delay circuit for delaying an output signal of the compression circuit by a predetermined time and an expansion circuit having a conversion rate controlled by a DC voltage generated correspondingly to a regulation of the volume controller, for expanding the output signal of the delay circuit according to a reverse conversion function to the compression conversion function to generate the echo signal.
    Type: Grant
    Filed: December 13, 1993
    Date of Patent: February 28, 1995
    Assignee: Rohm Co., Ltd.
    Inventors: Jun Hirai, Kaoru Izawa