The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 30, 1998
Filed:
Oct. 13, 1994
Masaki Eguchi, Uji, JP;
Fumio Kokubo, Kitakatsuragi-gun, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
An active controller suppressing an incoming acoustic wave by active control includes a signal processing unit filtering, an input signal corresponding to the incoming acoustic wave to generate an output signal, an error detecting portion detecting an error between the output signal and a desired response value, and an adapting portion adjusting a filtering characteristic of the signal processing portion according to the input signal, the output signal, and an error signal such that the error is minimized. The signal processing portion includes a non-recursive all zero digital filter filtering an input signal, and a lattice-type multi-stage all pole digital filter further filtering an output signal of the non-recursive all zero digital filter. The adapting portion updates a filter coefficient of the signal processing portion adaptively while clipping an absolute value exceeding one of a filter coefficient of the lattice-type multi-stage all pole digital filter.