Patents by Inventor Chitoshi Ishikawa

Chitoshi Ishikawa 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).

  • Patent number: 7276964
    Abstract: The present invention provides a PWM power amplifier and a method for controlling the same which can improve the sound quality significantly in real time. There is provided a PWM power amplifier and a method for controlling the same that PWM-power-amplifies an input audio signal to supply thus amplified audio signal to a speaker, which power-amplifies the audio signal, removes high frequency signal components included in the audio signal which is power-amplified, detects a distortion error raised in the audio signal which has its high frequency signal components removed based on the audio signal just about to be power-amplified, adjusts a voltage supplied from an external power source depending on a detected distortion error, and adjusts a voltage to be supplied at the time of the power amplification by a value corresponding to the distortion error so as to reduce the output impedance of the audio signal which has its high frequency signal components removed.
    Type: Grant
    Filed: October 28, 2005
    Date of Patent: October 2, 2007
    Assignee: Sony Corporation
    Inventor: Chitoshi Ishikawa
  • Publication number: 20060158245
    Abstract: The present invention provides a PWM power amplifier and a method for controlling the same which can improve the sound quality significantly in real time. There is provided a PWM power amplifier and a method for controlling the same that PWM-power-amplifies an input audio signal to supply thus amplified audio signal to a speaker, which power-amplifies the audio signal, removes high frequency signal components included in the audio signal which is power-amplified, detects a distortion error raised in the audio signal which has its high frequency signal components removed based on the audio signal just about to be power-amplified, adjusts a voltage supplied from an external power source depending on a detected distortion error, and adjusts a voltage to be supplied at the time of the power amplification by a value corresponding to the distortion error so as to reduce the output impedance of the audio signal which has its high frequency signal components removed.
    Type: Application
    Filed: October 28, 2005
    Publication date: July 20, 2006
    Applicant: SONY CORPORATION
    Inventor: Chitoshi Ishikawa