EP0647372A1 - Systeme de commande utilisant des filtres harmoniques - Google Patents

Systeme de commande utilisant des filtres harmoniques

Info

Publication number
EP0647372A1
EP0647372A1 EP92914435A EP92914435A EP0647372A1 EP 0647372 A1 EP0647372 A1 EP 0647372A1 EP 92914435 A EP92914435 A EP 92914435A EP 92914435 A EP92914435 A EP 92914435A EP 0647372 A1 EP0647372 A1 EP 0647372A1
Authority
EP
European Patent Office
Prior art keywords
harmonic
complex
signal
input signal
signals
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP92914435A
Other languages
German (de)
English (en)
Other versions
EP0647372A4 (fr
EP0647372B1 (fr
Inventor
Graham Eatwell
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Noise Cancellation Technologies Inc
Original Assignee
Noise Cancellation Technologies Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Noise Cancellation Technologies Inc filed Critical Noise Cancellation Technologies Inc
Priority to AT92914435T priority Critical patent/ATE180604T1/de
Publication of EP0647372A1 publication Critical patent/EP0647372A1/fr
Publication of EP0647372A4 publication Critical patent/EP0647372A4/fr
Application granted granted Critical
Publication of EP0647372B1 publication Critical patent/EP0647372B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1781—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions
    • G10K11/17821—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions characterised by the analysis of the input signals only
    • G10K11/17823—Reference signals, e.g. ambient acoustic environment
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1785—Methods, e.g. algorithms; Devices
    • G10K11/17853—Methods, e.g. algorithms; Devices of the filter
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1785—Methods, e.g. algorithms; Devices
    • G10K11/17853—Methods, e.g. algorithms; Devices of the filter
    • G10K11/17854—Methods, e.g. algorithms; Devices of the filter the filter being an adaptive filter
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1787—General system configurations
    • G10K11/17879—General system configurations using both a reference signal and an error signal
    • G10K11/17883—General system configurations using both a reference signal and an error signal the reference signal being derived from a machine operating condition, e.g. engine RPM or vehicle speed
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10—Applications
    • G10K2210/121—Rotating machines, e.g. engines, turbines, motors; Periodic or quasi-periodic signals in general
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/301—Computational
    • G10K2210/3028—Filtering, e.g. Kalman filters or special analogue or digital filters
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/301—Computational
    • G10K2210/3032—Harmonics or sub-harmonics
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/301—Computational
    • G10K2210/3051—Sampling, e.g. variable rate, synchronous, decimated or interpolated
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/50—Miscellaneous
    • G10K2210/512—Wide band, e.g. non-recurring signals

Definitions

  • the invention relates to a harmonic filter which is a signal processing means for obtaining the complex amplitude of a single harmonic component from a signal which contains one or more harmonic components.
  • the filter can be used in active or adaptive control systems for attenuating disturbances.
  • the approaches differ in the way the controller output is obtained and adjusted.
  • the output is generated by filtering reference signals.
  • the amplitude and phase of each signal is adjusted in the time domain by a variable filter as in Swinbanks, while in the other approach the controller output is updated in the frequency domain using the Discrete Fourier Transform of the residual signal as in Chaplin for varying frequencies, and for fixed frequencies in "Adaptive Filtering in the Frequency Domain” by Dentino et al, IEEE Proceedings, Vol 69, No. 12, pages 474-75 (1978).
  • the first approach can be implemented digitally by using a frequency sampling filter followed by a two-coefficient FIR filter or by using a frequency sampling filter followed by a Hilbert transformer and two single coefficient filters.
  • synchronous sampling has two disadvantages. Firstly, the anti-aliasing and smoothing filters must be set to cope with the slowest sampling rate. Since the upper control frequency is fixed, a large number of points may be required per cycle. Secondly, because of the varying sample rate, continuous system identification is complicated.
  • the system of this invention provides a method for obtaining the complex harmonic amplitudes of a single with varying fundamental frequency without the need for synchronous sampling.
  • the system can be used for both feedforward and feedback control.
  • a further object of this invention is to provide a harmonic filter control system for both feedforward and feedback systems.
  • Fig. 1 is a flow diagram of a harmonic filter comprising the invention
  • Fig. 2 shows an output processor for one harmonic
  • Fig. 3 is a diagrammatic view of a control system
  • Fig. 4a is a representative showing of a moving average FIR filter
  • Fig. 4b is a representative showing of a moving average recursive filter
  • Fig. 5 is a diagrammatic showing of a recursive harmonic filter
  • Fig. 6 is a diagram of a control system with on-line system identification.
  • This invention relates to a harmonic filter, and its use as part of a control system.
  • the harmonic filter is shown in Figure 1. It consists of a pair of multipliers and low-pass filters.
  • the input signal is multiplied by sinusoidal signals at the frequency of the harmonic component to be identified.
  • the resulting signals are passed through the low-pass filters.
  • the output from the low-pass filters are estimates of the real and imaginary parts of the desired complex harmonic amplitude.
  • the phase of the sinusoidal signal is determined from a phase signal (from a tachometer or a phase locked loop for example) or from integrating a frequency signal.
  • the bandwidth of the low-pass filter is variable and is determined by the fundamental frequency of the input signal.
  • sensors are used to provide signals indicative of the performance of the system. These signals are sent to harmonic filters and the complex output from the filters are used to adapt the controller output.
  • harmonic filters are combined with output processors and an adaptive controller.
  • the output processor for one harmonic is shown in Figure 2.
  • the real and imaginary parts of the complex amplitude of the output are determined by the controller. These are then multiplied by sinusoidal signals and summed to provide one harmonic of the output signal.
  • the sinusoidal signals are the same as those used in the harmonic filters.
  • Each harmonic of the controller output is generated by an output processor (01, 02, 03,.7) which combines a complex amplitude, Y with sine and cosine signals.
  • the controller output is obtained by summing these components. If the controller is to be used as part of an active control system, this output is then converted to the required form and sent to an actuator which produces the canceling disturbance.
  • the input to the controller is a residual or error signal r(t).
  • r(t) is responsive to the combination of the original disturbance and the canceling disturbance as measured by a sensor.
  • the residual signal is then passed to one or more harmonic filters (HF1, HF2, HF3, ).
  • the harmonic components, (Rl, R2, R3, ), of this residual signal are then used to adjust the complex amplitudes, (Yl, Y2, Y3, ), of the output.
  • a steady state, periodic signal r(t) can be written as a sum of harmonic components
  • the purpose of the harmonic filter is to determine the complex amplitudes R .
  • the complex amplitudes R are obtained by multiplying by a complex exponential and integrating over one or more complete cycles of the signal, so that
  • the harmonic filter is designed to provide a real-time estimate of the harmonic components of a signal.
  • the basic approach is to multiply the signal by the appropriate cosine and sine values and then to low-pass filter the results. This process, shown in
  • Figure 2 is equivalent to multiplying by a complex exponential signal, exp(ik ⁇ t), and then passing the result through a complex low-pass filter. The process is sometimes called heterodyning.
  • the multiplication by the complex exponential acts as demodulator, and the resulting signal has components at d.c. (zero frequency) and at twice the original frequency, for harmonic signals the harmonic frequencies are all shifted by +/- the frequency of the exponential signal, therefore the resulting signal may have components at the fundamental frequency. These must be filtered out to leave only the d.c. component.
  • the bandwidth of the filter With a fixed low-pass filter, the bandwidth of the filter must be set to cope with highest fundamental frequency likely to be encountered. When the system is operating at the lower frequencies, the low-pass filter is then much sharper than necessary, and therefore introduces much more delay than is necessary.
  • the bandwidth of the filter according to the current fundamental frequency it can be ensured that the harmonic filter has minimum delay. This is particularly important for use with control systems where any delay adversely affects the controller performance.
  • One way of implementing the low-pass filter is by a moving average process.
  • period P is defined as the time taken for the phases to change by 2 ⁇ radians, i.e.
  • the method is complicated by the fact that the period P is not generally an exact number of samples. If the sampling rate is high enough compared to the frequency of the harmonic being identified the truncation error can be neglected and the integral approximated by using the M samples in the current cycle. At time mT, the estimate can be obtained using a Finite Impulse Response (FIR) filter with M+l coefficients.
  • FIR Finite Impulse Response
  • Equation (5) The summation in equation (5) can be calculated recursively, that is, the next estimate can be calculated from the current estimate by adding in the new terms and subtracting off the old terms.
  • R k ((m+l)T) (P m /2) .R k (mT)
  • R k ((m+ 1 )T) ( 1 - e - a ⁇ T )r((m+ 1 )T)e -* «* + e ⁇ TR- ⁇ (mT), ( 10)
  • a a positive constant which determines the effective integration time
  • T the sampling period
  • ⁇ the fundamental frequency. Note that the bandwidth of the 'filter, i.e. the effective integration time, is scaled by the period of the noise. This is essential to obtain a uniform degree of independence of the harmonics.
  • the filter is shown in Figure 5. It can be implemented in analog or sampled data form.
  • Another advantage is that a can be varied dynamically to reduce the integration time during transients.
  • the bandwidth of the filter In order to separate out the different harmonic components, the bandwidth of the filter must be adjusted as the fundamental frequency of the disturbance varies. Note that the bandwidth of the filter is varied according to the fundamental frequency, not the frequency of the harmonic being identified.
  • the low-pass filter is designed to have zeros in its frequency response at multiple fundamental frequency.
  • There are many other ways of implementing low-pass filters with these properties which will be obvious to those skilled in the art of analog or digital filter design.
  • the exponential terms and sinusoidal terms used in the computation can be stored in a table.
  • the resolution of the table must be chosen carefully to avoid errors.
  • the exponential terms could be calculated at each output time, using interpolation from tabulated values, trigonometric identities or expansion formulae for example.
  • the controller output varies on the same time scale as the output from the harmonic filters (see co-pending patent application [13]).
  • the outputs from the harmonic filters are used directly as inputs to a non ⁇ linear control system.
  • the controller output In active control systems the controller output must have a particular phase relative to the disturbance to be controlled. In this case some output processing is required, which is effectively an inverse heterodyner.
  • nT which is calculated by the output processor
  • y(nT) ⁇ Re(Y k ) . cos(k ⁇ nT) - Im(Y k ) . sin(k ⁇ nT) ⁇ (11) where co is the fundamental radian frequency, Re denotes the real part and Im denotes the imaginary part, and where k is the harmonic number, K is the total number of harmonics in the signal and Y is the complex amplitude of the output at the appropriate harmonic.
  • the values Y can be stored in memory and the output calculated at each output time, as described by Ziegler.
  • the output processor uses the same sine and cosine terms as the input heterodyner.
  • the algorithms for adjusting the output values Y require knowledge of the harmonic components of the residual or error signal. These are provided by the outputs from the harmonic filters. Adaptive Algorithm
  • the known frequency domain adaptive algorithms can be used to update the complex amplitudes of the output.
  • a common choice for multichannel systems is to use
  • Y k n (l - ⁇ )Yr - ⁇ .B( ⁇ ).I ⁇ - > (12)
  • Y is the vector of outputs at the n-th update and the k-th harmonic
  • R is vector of residual components
  • ⁇ is the convergence step size
  • ⁇ is a leak applied to the output coefficients
  • B( ⁇ ) is a complex matrix related to the system transfer function matrix at the current frequency of this harmonic.
  • ⁇ can be a complex matrix related to A( ⁇ ) and B( ⁇ ). If the system transfer function is A( ⁇ ), then for the LMS algorithm,
  • a pseudo-inverse form is preferred since it allows the harmonic components to converge at equal rates - which is one of the main advantages of frequency domain algorithms. It is also preferred for multichannel systems since it allows for various spatial modes of the system to converge at a uniform rate.
  • the convergence step sizes for the algorithms which update at every sample are determined by the response time of the whole system. This is the settling time of the physical system (the time taken for the system to reach a substantially steady state) plus a variable delay due to the low-pass filter.
  • the constant ⁇ in (12) must be replaced by frequency dependent parameter, ⁇ ( ⁇ ). This parameter must take account of the effective delay in variable filter.
  • the constant ⁇ can also be replaced by a frequency dependent parameter ⁇ ( ⁇ ). This parameter can be adapted to limit the amplitude of the output.
  • the adaption process is performed every sample interval or at a rate determined by the cycle length (fundamental period) of the noise.
  • the first approach has the disadvantage that the sampling rate and/or the number of harmonics to be controlled is limited by the processing power of the controller.
  • the second approach has the disadvantage the computational requirements vary with the frequency, which may not be known in advance, and also the adaption rate is limited by the fundamental period of the disturbance.
  • the harmonic components are available every sample and the controller output is calculated every sample, but the adaption process can be performed at a slower rate if required.
  • this slower rate is determined in advance to be a fixed fraction of the sampling rate, in another embodiment of the invention the adaption is performed as a background task by the processor. This ensures that optimal use is made of the available processing power.
  • the sampled data control systems described above use constant sampling rates. This facilitates the use of on-line system identification techniques to determine the system impulse response (and hence it transfer function matrix). Some of these techniques are well known for time domain control systems. Tretter describes some techniques for multichannel periodic systems.
  • a random (uncorrelated) test signal is added to the controller output after the output processor but before the Digital to Analog Converter (DAC).
  • the response at each sensor is then measured before the heterodyner, but after the Analog to Digital Converter (ADC).
  • ADC Analog to Digital Converter
  • This response is then correlated with the test signal to determine a change to the relevant impulse response.
  • the correlation is estimated from a single sample.
  • Figure 6 This can be extended to multichannel system by applying the test signal to each actuator in turn or by using a different (uncorrelated) test signals for each actuator and driving all actuators simultaneously.
  • the plant in Figure 6 includes the DAC, smoothing filter, power amplifier, actuator, physical system, sensor, signal conditioning, anti-aliasing filter and ADC.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
  • Networks Using Active Elements (AREA)
  • Feedback Control In General (AREA)

Abstract

L'invention concerne des systèmes de commande d'atténuation du bruit actifs ou adaptatifs permettant d'obtenir une amplitude complexe d'une seule composante harmonique à partir d'un signal qui contient une composante harmonique ou davantage.
EP92914435A 1992-06-25 1992-06-25 Systeme de commande utilisant des filtres harmoniques Expired - Lifetime EP0647372B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT92914435T ATE180604T1 (de) 1992-06-25 1992-06-25 Steuerungssystem mit harmonischen filtern

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1992/005228 WO1994000911A1 (fr) 1992-06-25 1992-06-25 Systeme de commande utilisant des filtres harmoniques

Publications (3)

Publication Number Publication Date
EP0647372A1 true EP0647372A1 (fr) 1995-04-12
EP0647372A4 EP0647372A4 (fr) 1996-02-07
EP0647372B1 EP0647372B1 (fr) 1999-05-26

Family

ID=22231180

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92914435A Expired - Lifetime EP0647372B1 (fr) 1992-06-25 1992-06-25 Systeme de commande utilisant des filtres harmoniques

Country Status (5)

Country Link
EP (1) EP0647372B1 (fr)
CA (1) CA2138552C (fr)
DE (1) DE69229282T2 (fr)
DK (1) DK0647372T3 (fr)
WO (1) WO1994000911A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5361303A (en) * 1993-04-01 1994-11-01 Noise Cancellation Technologies, Inc. Frequency domain adaptive control system
JP3572486B2 (ja) * 1994-03-25 2004-10-06 本田技研工業株式会社 振動騒音制御装置
US5713438A (en) * 1996-03-25 1998-02-03 Lord Corporation Method and apparatus for non-model based decentralized adaptive feedforward active vibration control
CN112504616A (zh) * 2020-11-18 2021-03-16 中国空气动力研究与发展中心 一种天平动态力谐波抑制方法及装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4713782A (en) * 1984-08-23 1987-12-15 Hewlett-Packard Company Method and apparatus for measuring a transfer function
EP0351404A1 (fr) * 1987-03-11 1990-01-24 Ant Nachrichtentech Procede de synchronisation.
FR2675296A1 (fr) * 1991-04-12 1992-10-16 Mc Donnell Douglas Corp Procede et dispositif pour diminuer les vibrations.

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4328591A (en) * 1979-04-23 1982-05-04 Baghdady Elie J Method and apparatus for signal detection, separation and suppression
US4513249A (en) * 1979-04-23 1985-04-23 Baghdady Elie J Method and apparatus for signal detection, separation and suppression

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4713782A (en) * 1984-08-23 1987-12-15 Hewlett-Packard Company Method and apparatus for measuring a transfer function
EP0351404A1 (fr) * 1987-03-11 1990-01-24 Ant Nachrichtentech Procede de synchronisation.
FR2675296A1 (fr) * 1991-04-12 1992-10-16 Mc Donnell Douglas Corp Procede et dispositif pour diminuer les vibrations.

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO9400911A1 *

Also Published As

Publication number Publication date
DE69229282D1 (de) 1999-07-01
CA2138552A1 (fr) 1994-01-06
EP0647372A4 (fr) 1996-02-07
CA2138552C (fr) 1998-07-07
WO1994000911A1 (fr) 1994-01-06
EP0647372B1 (fr) 1999-05-26
DE69229282T2 (de) 2000-02-24
DK0647372T3 (da) 1999-12-06

Similar Documents

Publication Publication Date Title
US5469087A (en) Control system using harmonic filters
US5633795A (en) Adaptive tonal control system with constrained output and adaptation
JP2627807B2 (ja) 繰返し現象のための選択的能動キャンセレーションシステム
Glover Adaptive noise canceling applied to sinusoidal interferences
US4490841A (en) Method and apparatus for cancelling vibrations
JP2997490B2 (ja) 他の干渉する周期的雑音が存在する際に周期的信号を検知するための信号処理手段
Kim et al. Active control of multi-tonal noise with reference generator based on on-line frequency estimation
WO1994024970A1 (fr) Procedes de controle actif a blocs adaptatifs du bruit et des vibrations, a un ou plusieurs canaux, et equipements associes
CA2162245A1 (fr) Systeme de controle actif du bruit et des vibrations utilisant les signaux residuels pour creer les signaux de sondage
WO1994024970A9 (fr) Procedes de controle actif a blocs adaptatifs du bruit et des vibrations, a un ou plusieurs canaux, et equipements associes
US5577127A (en) System for rapid convergence of an adaptive filter in the generation of a time variant signal for cancellation of a primary signal
So Adaptive algorithm for sinusoidal interference cancellation
GB2107960A (en) Method and apparatus for cancelling vibrations
US5638022A (en) Control system for periodic disturbances
EP0647372B1 (fr) Systeme de commande utilisant des filtres harmoniques
JP3732227B2 (ja) 繰り返し事象を制御する適応制御システム
WO1994000911A9 (fr) Systeme de commande utilisant des filtres harmoniques
Kim et al. Delayed-X LMS algorithm: An efficient ANC algorithm utilizing robustness of cancellation path model
EP0805432A2 (fr) Méthode avec rétroaction pour contrÔle du bruit avec entrées et sorties multiples
JPH09511081A (ja) 時間領域適応制御システム
Kuo et al. Analysis and design of narrowband active noise control systems
Miljkovic Simple secondary path modeling for active noise control using waveform synthesis
CA2247808A1 (fr) Systeme actif de commande de retroaction pour rejet des perturbations a bande etroite transitoire sur une large plage spectrale
Paillard et al. Accelerating the convergence of the filtered-x LMS algorithm through transform-domain optimisation
Sujbert et al. Signal model based periodic noise controller design

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19941206

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IT LI LU MC NL SE

A4 Supplementary search report drawn up and despatched
AK Designated contracting states

Kind code of ref document: A4

Designated state(s): AT BE CH DE DK ES FR GB GR IT LI LU MC NL SE

17Q First examination report despatched

Effective date: 19970702

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH DE DK ES FR GB GR IT LI LU MC NL SE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19990526

Ref country code: ES

Free format text: THE PATENT HAS BEEN ANNULLED BY A DECISION OF A NATIONAL AUTHORITY

Effective date: 19990526

REF Corresponds to:

Ref document number: 180604

Country of ref document: AT

Date of ref document: 19990615

Kind code of ref document: T

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19990625

REF Corresponds to:

Ref document number: 69229282

Country of ref document: DE

Date of ref document: 19990701

ITF It: translation for a ep patent filed
ET Fr: translation filed
REG Reference to a national code

Ref country code: CH

Ref legal event code: NV

Representative=s name: PATENTANWALTSBUERO G. PETSCHNER

K2C3 Correction of patent specification (complete document) published

Effective date: 19990526

REG Reference to a national code

Ref country code: DK

Ref legal event code: T3

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19991231

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 20070427

Year of fee payment: 16

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20070507

Year of fee payment: 16

Ref country code: AT

Payment date: 20070507

Year of fee payment: 16

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DK

Payment date: 20070509

Year of fee payment: 16

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 20070605

Year of fee payment: 16

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 20070628

Year of fee payment: 16

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20070629

Year of fee payment: 16

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20070511

Year of fee payment: 16

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20070529

Year of fee payment: 16

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20070605

Year of fee payment: 16

BERE Be: lapsed

Owner name: *NOISE CANCELLATION TECHNOLOGIES INC.

Effective date: 20080630

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

REG Reference to a national code

Ref country code: DK

Ref legal event code: EBP

EUG Se: european patent has lapsed
GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20080625

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

Effective date: 20090101

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080630

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20090228

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090101

Ref country code: AT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080625

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090101

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080630

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080625

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080630

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080625

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080630

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DK

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090106

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DK

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080630

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080626