Patents by Inventor Lars Johan Brannmark

Lars Johan Brannmark 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: 8194885
    Abstract: A discrete-time audio precompensation filter is designed based on a linear model that describes the dynamic response of a sound generating system at p>1 listening positions. The filter construction is based on providing information representative of n non-minimum phase zeros {Zi} that are outside of the stability region |z|=1 in the complex frequency domain. A causal Finite Impulse Response (FIR) filter, of user-specified degree d, having coefficients corresponding to a causal part of a delayed non-causal impulse response is determined based on the information representative of n non minimum phase zeros. The resulting precompensation filter is determined as the product of at least two scalar dynamic systems, represented by an inverse of a characteristic scalar magnitude response in the frequency domain representing the power gains at the listening positions, and the causal FIR filter designed to approximately invert only non-minimum phase zeros that are safely inverted.
    Type: Grant
    Filed: March 20, 2008
    Date of Patent: June 5, 2012
    Assignee: Dirac Research AB
    Inventors: Lars Johan Brannmark, Mikael Sternad, Anders Ahlen
  • Publication number: 20090238380
    Abstract: A discrete-time audio precompensation filter is designed based on a linear model that describes the dynamic response of a sound generating system at p>1 listening positions. The filter construction is based on providing information (S2) representative of n non-minimum phase zeros {z,} that are outside of the stability region |z|=1 in the complex frequency domain. A causal Finite Impulse Response (FIR) filter, of user-specified degree d, having coefficients corresponding to a causal part of a delayed non-causal impulse response is determined (S4) based on the information representative of n non-minimum phase zeros.
    Type: Application
    Filed: March 20, 2008
    Publication date: September 24, 2009
    Applicant: DIRAC RESEARCH AB
    Inventors: Lars Johan BRANNMARK, Mikael STERNAD, Anders AHLEN