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:
Nov. 14, 2006
Filed:
Aug. 07, 2000
Hidekazu Tanaka, Matsusaka, JP;
Fumiyasu Konno, Hirakata, JP;
Hidekazu Tanaka, Matsusaka, JP;
Fumiyasu Konno, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A loudspeaker device comprising a power amplifier () to which an input signal is delivered via a subtracter (), a speaker unit () for reproducing output signals delivered from the power amplifier (), an acoustic pipe () coupled in front of the speaker unit for guiding the sound waves, a microphone () for detecting an acoustic outputs radiated from the speaker unit, a microphone amplifier () for amplifying an acoustic output signals detected by the microphone, and a negative feedback circuit. Output signals of the microphone amplifier are delivered to the subtracter, at the same time the same output signal is connected to a high-pass filter () to be delivered to the subtracter. Thus the negative feedback circuit is formed to suppress peaks and dips for providing a flattened sound pressure frequency characteristic.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile