Abstract:
Ein Flugzeugtriebwerk (10) mit einer Gasturbine (13) und einer Schallerzeugungsvorrichtung (14) zur aktiven Geräuschminderung der von der Gasturbine (13) erzeugten Betriebsgeräusche zeichnet sich dadurch aus, dass die Schallerzeugungsvorrichtung (14) mindestens einen elektrostatischen Flachlautsprecher (15) umfasst.
Abstract:
Flugzeugsitz (1) mit einem Audiosystem zur Wiedergabe von Audiodaten, wobei das Audiosystem eine Lautstärkenregelung und/oder eine Lärmkompensationsregelung sowie ein Kopfstützenelement (5) mit einem in einem Schwenkwinkel α schwenkbaren Lautsprecherelement (2) umfasst und wobei die Lautstärke und/oder der Grad der Lärmkompensation abhängig von dem Schwenkwinkel α geregelt ist.
Abstract:
The invention concerns a method and a device for actively reducing the level of a primary field of sound or vibration in a space (2). Control sensors (7) sense a parameter related to said level. Actuators (6) produce a secondary field of sound or vibration interfering with said primary field. A first transfer function matrix defines for each control sensor the level of the parameter caused by the actuator excitation. Monitor sensors (16) sense said parameter related to the level of the primary field. A second transfer matrix defines for each monitor sensor (16) the level caused by actuator excitation. A control unit (10) controls the actuators (6) by the relation between the first transfer matrix and the second transfer matrix, the control sensors (7) and the monitor sensors (16), and a residual vector of the actual level of the control sensors.
Abstract:
The present invention is embodied in an aircraft engine noise absorption system having a resonator cavity for absorbing incident noise except for a residue noise signal having a predominant frequency, the system comprising an actuator providing an actuator acoustic signal, a noise sensor for sensing the predominant frequency, and a control means for setting the actuator acoustic signal to the predominant frequency and varying one of a phase and an amplitude of the actuator acoustic signal to decrease the residue noise signal.
Abstract:
In the active muffler disclosed herein, a porous flow resistive member defines a wall of a duct carrying a noisy flow, e.g., a jet exhaust. The flow resistive member is characterized by having a flow resistance substantially less than rho C, the characteristic impedance of the acoustic medium. Loudspeakers in a chamber on the side of said porous member opposite the duct are actuated to reduce acoustic pressure in the region between the porous member and the loudspeaker, thereby increasing the acoustic flow through the porous member which in turn increases the dissipation of acoustic energy in the duct. The apparatus is particularly effective at low frequencies where a passive dissipative muffler would be of impractical size.
Abstract:
A method and system for reducing the acoustic levels of internal and external sound fields (23 and 24) generated by gas turbine engines (2) has several actuators to generate sound (50, 84, and 115), several sensors to measure the acoustic levels (49 and 69), and one or more controllers (113). The controllers are adaptive self-learning neural networks (112) that control the actuators to generate sound in order to effect the reduction of the internal and external sound field as measured by the sensors.
Abstract:
Apparatus for attenuating noise particularly in an aircraft cabin, comprises a diaphragm (10) one side of which is subjected to the noise, sensing means (16) for sensing the displacement of the diaphragm in response to the noise, and deflecting means (20) responsive to the sensing means for deflecting the diaphragm in order to cancel the displacement, to attenuate noise transmitted from one side of the diaphragm to the other side of the diaphragm.
Abstract:
La présente invention porte sur une méthode de détection acoustique d'au moins un dysfonctionnement (DYS) d'un moteur, le moteur générant un bruit primaire Po qui est traité par un système de contrôle actif du bruit émettant sur les cibles de réduction de bruit un signal acoustique Pc produit par au moins un actionneur et relié par une fonction de transfert H à un signal Y produit par ledit système de contrôle actif du bruit, ledit dysfonctionnement (DYS) ayant une signature acoustique identifiable dans le bruit primaire Po aux cibles de réduction de bruit, caractérisée en ce qu'elle comprend les étapes suivantes : acquisition dudit signal Y produit par le système de contrôle actif; identification de l'apparition éventuelle du dysfonctionnement par un moyen de surveillance qui exploite la connaissance de Y et de H et émet un message d'alerte le cas échéant.