Patents by Inventor Kheim V. Cai

Kheim V. Cai 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).

  • Digital voice detection apparatus and method using transform domain processing
    Patent number: 5365592
    Abstract: A waveform characterizer apparatus is disclosed for extracting cepstrum pitch and spectral properties of a waveform signal such as the baseband audio output of a receiver. The apparatus employs Fourier processing, cepstral processing, magnitude detection, logarithms processing, frequency selective filtering and time/frequency windowing to extract cepstrum pitch and spectral rolloff characteristics which can then be used to determine the signal type. One application of the invention is in a digital voice/squelch apparatus.
    Type: Grant
    Filed: July 19, 1990
    Date of Patent: November 15, 1994
    Assignee: Hughes Aircraft Company
    Inventors: Robert W. Horner, Kheim V. Cai, Ronald L. Bergen, Keith A. Lane