Patents by Inventor Keiichiro Ogura

Keiichiro Ogura 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).

  • Discrete 4-channel stereo recording and/or reproducing system compatible with matrix systems
    Patent number: 4115666
    Abstract: A discrete 4-channel stereo recording and reproducing system which is based on a regular matrix type 4-channel stereo system and compatible with both of a regular matrix system and a CD-4 type 4-channel stereo system. In the audio frequency band, the same encoding as that in the regular matrix system is performed and, in the carrier frequency band, encoding for satisfying the compatibility with existing systems is achieved. The decoding is intended to improve the sound image location and separation in the reproduced sound field from CD-4 type stereo signals and automatic switching of a decoding circuit for the regular matrix type signals is achieved.
    Type: Grant
    Filed: August 13, 1976
    Date of Patent: September 19, 1978
    Assignee: Nippon Columbia Kabushikikaisha
    Inventor: Keiichiro Ogura