公开(公告)号：EP0555248B1

公开(公告)日：1998-05-13

申请号：EP91918077.8

申请日：1991-10-22

Applicant: NOISE CANCELLATION TECHNOLOGIES, INC.

Inventor： ROSS, Colin, Fraser Grove House Bury Road ,  EATWELL, Graham, Paul

IPC: G10K11/16

CPC classification number: G10K11/178 ,  G10K2210/3012 ,  G10K2210/3018 ,  G10K2210/3019 ,  G10K2210/3045 ,  G10K2210/3046

Abstract: An active vibration control system having at least two input sensors generating first signals representative of a primary vibration field, a plurality of actuators driven by second signals and producing a secondary vibration field, monitoring sensors responsive to both the primary and secondary vibration fields and producing third signals, and a controller having one output waveform generator for each second signal and responsive to the first signals to generate respective second signals so that vibration is reduced in a chosen region excited by both the primary and secondary fields, the controller being adaptive to adjust the waveform generator outputs to maintain the reduced vibration in this region.

公开(公告)号：EP0624274B1

公开(公告)日：1998-04-15

申请号：EP93902465.9

申请日：1993-01-27

Applicant: NOISE CANCELLATION TECHNOLOGIES, INC.

Inventor： CURTIS, Alan, Robert, Douglas

IPC: G10K11/16

CPC classification number: H03H21/0012 ,  G10K11/178 ,  G10K2210/121 ,  G10K2210/30232 ,  G10K2210/3032 ,  G10K2210/3033 ,  G10K2210/3045 ,  G10K2210/3212 ,  H03H2021/0089

Abstract: The invention relates to an improvement to a so-called filtered-x active noise reduction system, in which a cyclic reference signal (x), generally synchronous with primary noise (p) to be cancelled, is applied to a control filter (6) that adaptively filters the reference signal (q) to drive an actuator (3) so as to produce secondary noise (s) for cancelling the primary noise. An error signal microphone (4) detects the residual (r) of the primary and secondary noise. A model filter (8) filters the reference signal (x) and has a filtering characteristic selected to model the transfer function for said secondary noise from the actuator through the microphone (4). An LMS controller (7) responsive to said filtered reference signal and the detected residual (r) adaptively controls the control filter (6) so as to tend to minimise the residual (r). The model filter (8) has its filtering characteristics selectible for different frequencies of the reference signal (x) and a sensor (14) is used to detect the operating frequency so that the filtering characteristic of the model filter can be selected in dependence upon the sensed frequency.

公开(公告)号：EP0579667B1

公开(公告)日：1998-03-25

申请号：EP92908134.7

申请日：1992-04-09

Applicant: NOISE CANCELLATION TECHNOLOGIES, INC.

Inventor： NADIM, Mohammed

IPC: G10K11/16

CPC classification number: F16F15/02 ,  G10K11/178 ,  G10K2210/107 ,  G10K2210/129 ,  G10K2210/3011 ,  G10K2210/3031 ,  G10K2210/3032 ,  G10K2210/3045 ,  G10K2210/3051

Abstract: PCT No. PCT/GB92/00642 Sec. 371 Date Dec. 6, 1993 Sec. 102(e) Date Dec. 6, 1993 PCT Filed Apr. 9, 1992 PCT Pub. No. WO92/18975 PCT Pub. Date Oct. 29, 1992.Primary vibrations (N), e.g. acoustic noise or vibration from a source thereof such as a motor, are cancelled by secondary vibrations (C) produced by an actuator (2) driven by a controller (3) that is responsive to an error signal (E) detected by a detector (4) and representative of the residual or difference between the primary and secondary vibrations. The controller samples the error signal (E) during successive sampling periods determined by a synchronising signal (syn) taken from the motor. The secondary vibrations Cn+1 for a sampling period n+1 are determined as follows: Cn+1=Cn- mu EnSGN[1/ &upbar& H], where Cn represents the secondary vibrations produced during a preceding sampling period (n); En represents the detected error signal for said preceding period n, H represents the transfer coefficient between the actuator (2) and the detector (4) and mu is a scaling factor where 0

公开(公告)号：EP0596971B1

公开(公告)日：1997-11-12

申请号：EP92916388.9

申请日：1992-07-28

Applicant: NOISE CANCELLATION TECHNOLOGIES, INC.

Inventor： JONES, Owen ,  TRINDER, Michael, Charles, John

IPC: G10K11/16

CPC classification number: G10K11/178 ,  G10K2210/121 ,  G10K2210/3028 ,  G10K2210/3032 ,  G10K2210/3045 ,  G10K2210/3211 ,  G10K2210/3212

Abstract: PCT No. PCT/GB92/01399 Sec. 371 Date May 26, 1994 Sec. 102(e) Date May 26, 1994 PCT Filed Jul. 28, 1992 PCT Pub. No. WO93/03479 PCT Pub. Date Feb. 18, 1993A system for reducing periodic noise, which includes a plurality of harmonically related noise signals, comprises an actuator for producing a canceling acoustic signal, a sensor for detecting a residual noise signal, a synchronizing signal generator and processing circuitry. The processing circuitry comprises a plurality of tunable harmonically related band pass filters, a tuning signal generator and a summer which sums the outputs of the filters. The tuning signal generator receives the synchronizing signal from the synchronizing signal generator and outputs the tuning signals to the band pass filters. As the frequency of the synchronizing signal changes, the tuning signal generator causes the tunable filters to track harmonics of the noise to be canceled. After summing by the summer and suitable amplification, the outputs from the filters are used to drive the actuator so as to reduce the residual noise detected by the sensor.

Abstract translation: 一种用于减少包括多个谐波相关噪声信号的周期性噪声的系统包括用于产生消除声信号的致动器（1），用于检测残余噪声信号的传感器（3），同步信号产生装置（7）和 处理电路（4-1，... 4-n，5，6）。 处理电路包括多个可调和的谐波相关带通滤波器（4-1，... 4-n），调谐信号发生器（6）和加法器（5），其将滤波器（4-1， ，... 4-n）。 调谐信号发生器（6）接收来自同步信号发生装置（7）的同步信号并将调谐信号输出到带通滤波器（4-1，... 4-n）。 当同步信号的频率改变时，调谐信号发生装置（6）使可调谐滤波器（4-1，... 4-n）跟踪要消除的噪声的谐波。 在加法器（5）和适当的放大相加之后，来自滤波器（4-1，... 4-n）的输出被用于驱动致动器（1），以减少由传感器检测到的残余噪声 3）。 在一个实施例中，滤波器（4-1，...，4-n）通过开关电容滤波器来实现。

公开(公告)号：EP0786051A2

公开(公告)日：1997-07-30

申请号：EP95944835.0

申请日：1995-10-11

Applicant: NOISE CANCELLATION TECHNOLOGIES, INC.

Inventor： DENENBERG, Jeffrey, N.

IPC: F04D29 ,  G10K11

CPC classification number: G10K11/178 ,  F04D29/663 ,  F04D29/665 ,  F05B2260/962 ,  G10K2210/109 ,  G10K2210/112

Abstract: A ducted axial fan for large diameter ducts (11) which includes equidistantly spaced sensors (22, 23) upstream and downstream of an axial fan and spaced actuators (24, 26) located around the periphery of said duct to cancel tonal noise caused by the air turbulence generated by the rotation of the fan.

公开(公告)号：EP0516695B1

公开(公告)日：1997-04-09

申请号：EP91904859.5

申请日：1991-02-20

Applicant: NOISE CANCELLATION TECHNOLOGIES, INC.

Inventor： ROSS, Colin Fraser ,  LANGLEY, Andrew John ,  EATWELL, Graham Paul

IPC: G10K11/16

CPC classification number: G10K11/178 ,  G10K2210/108 ,  G10K2210/1081 ,  G10K2210/121 ,  G10K2210/3011 ,  G10K2210/3018 ,  G10K2210/511

Abstract: An active control system for attenuating tonal noise in a defined region is described. In its most basic form the system includes sensors (1, 8) for generating signals indicative of the residual noise in the region after attenuation and the uncontrolled sound affecting the region, signal processing circuits (10, 26) for processing the generated signals differently depending on the tonal content thereof, an adaptive filter (5) supplied with at least one of the generated signals whose characteristic is controlled by the processing circuitry (10), a transducer (6) for producing tonal-noise-attenuating disturbance in the region and delay means (4) for delaying signals relating to the uncontrolled noise before or after or during the adaptive filtering. The system finds direct application in a personal headset or ear defender.

Abstract translation: 描述了用于衰减定义区域中的音调噪声的主动控制系统。 在其最基本的形式中，该系统包括用于产生指示衰减之后区域中的残留噪声和影响该区域的不受控声音的信号的传感器（1,8），用于以不同方式处理所产生的信号的信号处理电路（10,26） 在其音调内容上提供自适应滤波器（5），该自适应滤波器（5）提供有其特征由处理电路（10）控制的至少一个所产生的信号，用于在该区域中产生音调噪声衰减干扰的变换器（6） 延迟装置（4），用于在自适应滤波之前或之后延迟与不受控噪声有关的信号。 该系统可以直接应用于个人耳机或耳后卫。

公开(公告)号：EP0705471A1

公开(公告)日：1996-04-10

申请号：EP94921355.0

申请日：1994-06-22

Applicant: NOISE CANCELLATION TECHNOLOGIES, INC.

Inventor： JONES, Owen

IPC: G10K11

CPC classification number: G10K11/178 ,  G10K2210/1081 ,  G10K2210/3028 ,  G10K2210/3039 ,  G10K2210/3045

Abstract: The susceptibility of an active noise cancellation system to overloading due to very low frequencies is reduced by subtracting the low frequency components of an applied noise field from the residual signal. Low frequency components of the applied noise field outside the normal range of human hearing are detected by an external sensor and isolated by a filter circuit. The isolated low frequency signal is subtracted from the residual signal, resulting in a modified residual signal with reduced low frequency components. The cancellation system thus eliminates very low frequency cancellation signals, without sacrificing bandwidth or system performance within the audible range.

Abstract translation: 通过从残余信号中减去所施加的噪声场的低频分量来减少主动噪声消除系统由于非常低的频率而导致的过载的敏感度。 外部传感器（14）检测在人听力正常范围之外的施加噪声场的低频分量，并由滤波器电路（15）隔离。 从残余信号中减去隔离的低频信号，产生具有减少的低频分量的修改的残余信号。 消除系统因此消除了非常低的频率消除信号，而不牺牲可听范围内的带宽或系统性能。

公开(公告)号：EP0698298A1

公开(公告)日：1996-02-28

申请号：EP94914908.0

申请日：1994-05-04

Applicant: NOISE CANCELLATION TECHNOLOGIES, INC.

Inventor： HILDEBRAND, Stephen

IPC: H01L41

CPC classification number: H01L41/0973 ,  H01L41/098

Abstract: A low voltage bender piezo-actuator with multiple, same size piezo layers (11, 12) separated by thin electrically conductive strips (14) and adapted to be affixed to a rigid, vibration transmitting plate (10) to produce noise counter vibrations to prevent noise from passing through the plate.

公开(公告)号：EP0695452A1

公开(公告)日：1996-02-07

申请号：EP94913315.0

申请日：1994-04-01

Applicant: NOISE CANCELLATION TECHNOLOGIES, INC.

Inventor： EATWELL, Graham, P.

IPC: G10K11

CPC classification number: G10K11/178 ,  G10K2210/117 ,  G10K2210/3025 ,  G10K2210/3042 ,  G10K2210/3046 ,  G10K2210/3053 ,  G10K2210/3057

Abstract: A multiple-input, multiple-output adaptive control system which utilizes perturbations to the frequency components of the outputs to determine the desired changes to said coefficients. The control system is particularly suited to the active control of noise and vibration.

公开(公告)号：EP0694234A1

公开(公告)日：1996-01-31

申请号：EP92914496.0

申请日：1992-06-25

Applicant: NOISE CANCELLATION TECHNOLOGIES, INC.

Inventor： EATWELL, Graham

IPC: G10K11

CPC classification number: G10K11/178 ,  G10K2210/121 ,  G10K2210/3028 ,  G10K2210/3032 ,  G10K2210/3045

Abstract: A control system for controlling periodic disturbances employing a delay inverse filter (5) for supplying a signal, in response to a disturbance signal received by a sensor (1), a variable delay circuit (6) which is adjusted such that the delay through the delayed inverse filter and the variable delay is equal to a whole number of cycles of the disturbance signal. The output from said variable delay circuit being supplied to an actuator (9) such that it is combined with said disturbance signal at the sensor.