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:
Feb. 21, 1989
Filed:
Jul. 07, 1987
Masahiko Kato, Nukata, JP;
Masanori Katou, Toyoake, JP;
Satosi Kuwakado, Nukata, JP;
Katsuyuki Tanaka, Nishio, JP;
Koji Ito, Anjo, JP;
Nippondenso Co., Ltd., Kariya, JP;
Nippon Soken, Inc., Nishio, JP;
Abstract
An active silencer provided in a pipe which has one end reaching the noise source and the other end open, the active silencer being provided with a sound generating means which is provided at the sidewall of the pipe facing inside the pipe, a sound collecting means which is provided outside the pipe close to the other end and which detects noise dissipated from the pipe opening, a phase leading means which outputs a lead phase output signal which is advanced from the phase of an output signal of the sound collecting means by a phase corresponding to a predetermined time determined by the distance between the sound generating means and the sound collecting means; and a drive means which outputs a signal constituting the lead phase output signla inverted in phase as a drive signal for the sound generating means, the predetermined time .tau. being set so that .tau.=L/C, wherein the distance between the sound generating means and the sound collecting means is L and the speed of sound is C.