Patents by Inventor Birru M. Dagnachew

Birru M. Dagnachew 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).

  • Video rate D/A converter with sigma-delta modulator
    Patent number: 6236345
    Abstract: A D/A converter (DAC) is described having interpolation means (1) and filter means. Further the D/A converter comprises a noise shaper (3) implemented as a reduced sample rate (RSR) sigma delta modulator, and controlled by clock means. To further improve the operation of the D/A converter in an advantageous embodiment of the invention the filter means are implemented as polyphase FIR filter means.
    Type: Grant
    Filed: April 26, 1999
    Date of Patent: May 22, 2001
    Assignee: U.S. Philips Corporation
    Inventors: Birru M. Dagnachew, Engel Roza
  • Reduced complexity signal converter
    Patent number: 5980097
    Abstract: In a signal converter which derives from an input signal having a sample rate R/q an output signal having a larger sample rate R, the input signal is combined with a feedback signal in a subtracter to form a single combined signal. Samples of the combined signal are mapped into a larger number of output samples by a mapper forming part of a mapping arrangement which also produces the feedback signal. The formation of a single combined signal makes the signal converter less complex in design than it would be if a number of combined signals were formed. In a further embodiment a noise shaping filter is interposed between the subtracter and the mapper.
    Type: Grant
    Filed: February 6, 1997
    Date of Patent: November 9, 1999
    Assignee: U.S. Philips Corporation
    Inventor: Birru M. Dagnachew