US20180322859A1 - Realisation of controller transfer function for active noise cancellation - Google Patents
Realisation of controller transfer function for active noise cancellation Download PDFInfo
- Publication number
- US20180322859A1 US20180322859A1 US15/812,543 US201715812543A US2018322859A1 US 20180322859 A1 US20180322859 A1 US 20180322859A1 US 201715812543 A US201715812543 A US 201715812543A US 2018322859 A1 US2018322859 A1 US 2018322859A1
- Authority
- US
- United States
- Prior art keywords
- filter
- transfer function
- filters
- adjustable parameter
- noise cancellation
- 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.)
- Abandoned
Links
Images
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
- G10K11/1787—General system configurations
- G10K11/17875—General system configurations using an error signal without a reference signal, e.g. pure feedback
-
- 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
-
- 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
- G10K11/17813—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 acoustic paths, e.g. estimating, calibrating or testing of transfer functions or cross-terms
- G10K11/17817—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 acoustic paths, e.g. estimating, calibrating or testing of transfer functions or cross-terms between the output signals and the error signals, i.e. secondary path
-
- 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
- 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
- G10K2210/3056—Variable gain
Definitions
- This invention relates to active noise cancellation systems, and has application to both feedback and feedforward control architectures, or combinations of these.
- All active noise cancellation products whether they are based on a feedback or feedforward control architecture (or a combination of these two architectures) require a tailored transfer function between the noise sensing device (typically one or more sensing microphones) and the device that creates the acoustic response required to cancel the sensed noise (typically a speaker).
- the transfer function between the sensing microphone (s) and the speaker is referred to as the control law transfer function. This transfer function facilitates the realisation of noise cancellation over a suitable bandwidth whilst minimising noise amplification and and/or instability outside this bandwidth.
- the disclosed subject matter provides apparatus for realising an active noise cancellation control law transfer function between a sensing microphone and a speaker, the apparatus including a plurality of filters, each filter being operable over a different frequency range, and at least one filter having at least one adjustable parameter whereby the filter can be adjusted such that the filters cumulatively realise a required control law transfer function.
- Each filter may include at least one adjustable parameter.
- the adjustable parameter is amplitude. In other embodiments the adjustable parameter is bandwidth.
- the adjustable filter may comprise a parametric filter.
- the adjustable parameter is dynamically adjustable.
- An adjustment controller may be provided to adjust the adjustable parameter.
- the disclosed subject matter broadly provides a method of active noise cancellation for apparatus including a speaker and sensing microphone and a plurality of filters, each filter being operable over a different frequency range, and at least one filter having at least one adjustable parameter whereby the filter can be adjusted, the method including:
- the disclosed subject matter broadly provides a method of active noise cancellation for apparatus including a speaker and sensing microphone and a plurality of filters, each filter being operable over a different frequency range, and at least one filter having at least one adjustable parameter whereby the filter can be adjusted, the method including:
- the method may further comprise dynamically adjusting the adjustable parameter.
- FIG. 1 Is a diagrammatic representation of a known feedback active noise cancellation system.
- FIG. 2 Is a diagram showing gain plotted against frequency for the desired response for a known control law a transfer function for an active noise cancellation system such as that shown diagrammatically in FIG. 1
- FIG. 3 Is a circuit diagram showing one example of a possible circuit realisation of a control law transfer function such as that represented in FIG. 2 .
- FIG. 4 Is a diagrammatic representation of a feedback active noise cancellation system according to one embodiment of the invention.
- a known active noise cancellation system in which a speaker or driver 1 delivers sound in a selected region, usually the enclosed space between a headset or earphone and the user's inner ear, for example.
- the sound from loudspeaker 1 is sensed by sensing microphone(s) 2 , which also senses any noise N in the selected region.
- a controller 3 receives the output from the sensing microphone(s) 2 and applies an appropriate control law to actuate the speaker 1 such that the noise N is effectively cancelled.
- the controller 3 In order to provide an appropriate signal to speaker 1 , the controller 3 must realise a suitable control law transfer function between the sensing microphone (s) and speaker.
- FIG. 2 a plot of gain against frequency for a control law transfer function known for use in the active noise cancellation system as broadly outlined in FIG. 1 is shown.
- the general form of the function includes an amplitude peak at around 300 Hz, a notch at approximately 8 kHz, and a rising characteristic above 10 kHz.
- a solution which uses a plurality of filters having one or more adjustable parameters.
- the filters are each operable over a different selected frequency range in a similar manner to a multi-channel audio equaliser.
- the filters may cumulatively realise a required control law transfer function.
- the proposed solution uses parametric filters, although those skilled in the art will appreciate that other forms of filter may be used.
- the resultant circuit construction may take a variety of physical forms, and may in some embodiments be provided in the form of an integrated circuit with few, if any, additional components.
- a parametric filter allows adjustment of centre frequency, quality factor (Q) and amplitude. Therefore, a parametric filter provides significant flexibility for an application such as the realisation of a selected frequency band of a control law transfer function.
- Control law transfer functions are invariably based on a minimum phase system, and therefore the amplitude and phase characteristics are uniquely related. Accordingly, one only needs to realise the desired amplitude response and the phase response will automatically follow, or vice versa.
- the adjustable parameter for one or more of the filters may simply be amplitude.
- a plurality of parametric filters may be used together, in a manner similar to use of a parametric equaliser, to realise a control law transfer function.
- any amplitude shape i.e. any gain profile with respect to frequency can be realised over a selected bandwidth and so it is possible to realise any desired or required control law transfer function.
- multiple filter parameters of multiple filters are adjustable.
- only a single parameter of a single filter of the plurality of filters may be adjustable.
- control law transfer function characteristic illustrated in FIG. 2 it will be seen that this may be sufficiently well matched with a filter arrangement that is analogous to a “2.5” channel parametric equaliser, i.e. two parametric filters and a shelving filter.
- the first and second channels correspond to two parametric filters that are fully featured and cover the 300 Hz peak at 8 KHz notch.
- the third channel corresponds to a shelving filter with a frequency and amplitude adjustment only (i.e. no Q).
- the amplitude of a parametric equaliser is typically centred around 0 dB, so a separate adjustable gain stage is used to realise the final control or transfer function. In this example around 12 dB of gain is provided by this stage.
- the “ESRC” block provides the overall system gain
- the 40 k potentiometers set the channel amplitude
- the 1 k adjustable resistors set the channel Q (which determines the bandwidth over which the filter operates) for the peak and the notch
- the frequency of the shelf the 100 k adjustable resistors set the channel frequency for the peak and the notch.
- the external component count is therefore only two capacitors (per left or right channel).
- the adjustable resistor settings can be programmed into the integrated circuit as a one time programmable (OTP) setting.
- FIG. 4 shows a system according to an embodiment of the invention in which the control law transfer function is realised by a controller 3 incorporating a plurality of filters (such as the arrangement shown in FIG. 3 ), at least one of the filters having an adjustable parameter.
- the FIG. 4 embodiment includes a dynamic performance adjustment controller 4 which sensing the noise cancellation performance of the apparatus comprising the system by monitoring the noise signal detected by the sensing microphone 2 and sends the necessary signals or instructions to the controller 3 to dynamically adjust one or more adjustable parameters of one or more of the filters that realise the control law transfer function.
- the adjustment controller 4 includes a digital signal processor which periodically monitors the signal from noise sensing microphone 2 and determines which parameters of the controller 3 require adjustment. Appropriate output signals (either analog or digital) are generated and provided to the controller 3 to make the required adjustment. The sensing microphone signal can then be used again to determine whether the adjustment is successful, and to what extent further adjustment is required.
- the invention may be used in association with an active noise cancellation device such as an active noise cancelling headset or earphone.
- the filters may be part of the device.
- the filters may be remotely associated with the device, for example being provided in a remote control module. It will be seen that the invention allows continual or periodic monitoring of one or more acoustic or electro-acoustic characteristics of the active noise cancelling device so that the filter(s) can be adjusted to realise a control law transfer function dependent on the determined characteristic(s).
- the invention allows a generic filter circuit to be used which can be adjusted for different models or forms of active noise cancelling device.
- the invention may allow each specific device produced from a production line to be tested for one or more acoustic or electro-acoustic characteristics, so that the control law transfer function for each specific device may be adjusted to optimise performance of that device to account for manufacturing tolerances.
- the invention provides an adjustable transfer function that is amenable to integration with a low external part count.
- a digital realisation has the disadvantages of requiring high speed, low latency analog to digital and digital to analog conversion as well as the digital signal processing elements. This all comes at a cost in terms of power consumption, noise floor and price amongst others.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Abstract
An apparatus for realizing an active noise cancellation control law transfer function between a sensing microphone and a speaker. The apparatus includes a multiplicity of filters. Each filter is operable over a different frequency range. At least one filter has an adjustable parameter whereby the filter can be adjusted such that the filters cumulatively realize a required control law transfer function. The adjustable parameter may in one embodiment be the amplitude. In other embodiments, it may be other parameters.
Description
- This application is a continuation of U.S. patent application Ser. No. 12/956,200, filed on Nov. 30, 2010, which claims the benefit of and priority from U.S. Provisional Patent Application No. 61/264,995, filed Nov. 30, 2009. Both of these prior applications are herein incorporated by reference in their entirety.
- This invention relates to active noise cancellation systems, and has application to both feedback and feedforward control architectures, or combinations of these.
- All active noise cancellation products, whether they are based on a feedback or feedforward control architecture (or a combination of these two architectures) require a tailored transfer function between the noise sensing device (typically one or more sensing microphones) and the device that creates the acoustic response required to cancel the sensed noise (typically a speaker). In this document the transfer function between the sensing microphone (s) and the speaker is referred to as the control law transfer function. This transfer function facilitates the realisation of noise cancellation over a suitable bandwidth whilst minimising noise amplification and and/or instability outside this bandwidth.
- Classically the control law transfer function has been realised through use of an analog filter which consists of a fixed combination of active and passive components. Such a realisation has the following disadvantages:
-
- 1. Its fixed nature does not allow adjustment of production variation within the electro-acoustics to which it interfaces.
- 2. Its fixed nature does not allow easy accommodation of a range of electro-acoustic designs.
- 3. Its fixed nature does not permit dynamic adjustment of the control law to provide optimised noise cancellation based on the prevailing noise field.
- 4. The component count of the implementation is high and typically does not lend itself to integration within an integrated circuit.
- It is an object of the present invention to provide a method or apparatus for realising an active noise cancellation control law transfer function which will ameliorate at least one of the foregoing disadvantages, or which, alternatively, will at least provide a useful alternative to existing solutions.
- In one aspect the disclosed subject matter provides apparatus for realising an active noise cancellation control law transfer function between a sensing microphone and a speaker, the apparatus including a plurality of filters, each filter being operable over a different frequency range, and at least one filter having at least one adjustable parameter whereby the filter can be adjusted such that the filters cumulatively realise a required control law transfer function.
- Each filter may include at least one adjustable parameter. In some embodiments the adjustable parameter is amplitude. In other embodiments the adjustable parameter is bandwidth.
- The adjustable filter may comprise a parametric filter.
- In one embodiment the adjustable parameter is dynamically adjustable. An adjustment controller may be provided to adjust the adjustable parameter.
- In another aspect the disclosed subject matter broadly provides a method of active noise cancellation for apparatus including a speaker and sensing microphone and a plurality of filters, each filter being operable over a different frequency range, and at least one filter having at least one adjustable parameter whereby the filter can be adjusted, the method including:
-
- determining one or more acoustic or electro-acoustic characteristics of the apparatus, and;
- adjusting the adjustable parameter dependent on the characteristic such that the filters cumulatively realise a control law transfer function to implement active noise cancellation.
- In another aspect the disclosed subject matter broadly provides a method of active noise cancellation for apparatus including a speaker and sensing microphone and a plurality of filters, each filter being operable over a different frequency range, and at least one filter having at least one adjustable parameter whereby the filter can be adjusted, the method including:
-
- sensing the noise cancellation performance of the apparatus, and;
- adjusting the adjustable parameter dependent on the sensed performance such that the filters cumulatively realise a control law transfer function to implement active noise cancellation.
- The method may further comprise dynamically adjusting the adjustable parameter.
- Further aspects will become apparent from the following description.
- One or more embodiments of the invention will be described below with reference to the drawings in which:
-
FIG. 1 : Is a diagrammatic representation of a known feedback active noise cancellation system. -
FIG. 2 : Is a diagram showing gain plotted against frequency for the desired response for a known control law a transfer function for an active noise cancellation system such as that shown diagrammatically inFIG. 1 -
FIG. 3 : Is a circuit diagram showing one example of a possible circuit realisation of a control law transfer function such as that represented inFIG. 2 . -
FIG. 4 : Is a diagrammatic representation of a feedback active noise cancellation system according to one embodiment of the invention. - Referring to
FIG. 1 , a known active noise cancellation system is shown in which a speaker or driver 1 delivers sound in a selected region, usually the enclosed space between a headset or earphone and the user's inner ear, for example. The sound from loudspeaker 1 is sensed by sensing microphone(s) 2, which also senses any noise N in the selected region. Acontroller 3 receives the output from the sensing microphone(s) 2 and applies an appropriate control law to actuate the speaker 1 such that the noise N is effectively cancelled. - In order to provide an appropriate signal to speaker 1, the
controller 3 must realise a suitable control law transfer function between the sensing microphone (s) and speaker. - Turning now to
FIG. 2 , a plot of gain against frequency for a control law transfer function known for use in the active noise cancellation system as broadly outlined inFIG. 1 is shown. As can be seen fromFIG. 2 , the general form of the function includes an amplitude peak at around 300 Hz, a notch at approximately 8 kHz, and a rising characteristic above 10 kHz. - In order to realise the function shown, a solution is proposed which uses a plurality of filters having one or more adjustable parameters. The filters are each operable over a different selected frequency range in a similar manner to a multi-channel audio equaliser. Thus the filters may cumulatively realise a required control law transfer function. In one embodiment, the proposed solution uses parametric filters, although those skilled in the art will appreciate that other forms of filter may be used. Those skilled in the art will also realise that the resultant circuit construction may take a variety of physical forms, and may in some embodiments be provided in the form of an integrated circuit with few, if any, additional components.
- A parametric filter allows adjustment of centre frequency, quality factor (Q) and amplitude. Therefore, a parametric filter provides significant flexibility for an application such as the realisation of a selected frequency band of a control law transfer function.
- Control law transfer functions are invariably based on a minimum phase system, and therefore the amplitude and phase characteristics are uniquely related. Accordingly, one only needs to realise the desired amplitude response and the phase response will automatically follow, or vice versa. Hence in some embodiments the adjustable parameter for one or more of the filters may simply be amplitude.
- In one embodiment a plurality of parametric filters may be used together, in a manner similar to use of a parametric equaliser, to realise a control law transfer function. In particular, if there is a sufficient number of filters (for example being analogous to a parametric equaliser with a number of channels) and range of adjustment, any amplitude shape i.e. any gain profile with respect to frequency can be realised over a selected bandwidth and so it is possible to realise any desired or required control law transfer function. In some embodiments, multiple filter parameters of multiple filters are adjustable. In other embodiments, only a single parameter of a single filter of the plurality of filters may be adjustable.
- In practice, it is usually necessary to rationalise the number of channels, i.e. the number of filters and the range of adjustment in order to minimise circuit complexity. However, if appropriate informed design choices are made, then because of the inherent flexibility of each parametric filter, a wide range of control law transfer functions can still be approximated to a sufficient level of accuracy.
- Therefore, turning to the control law transfer function characteristic illustrated in
FIG. 2 , it will be seen that this may be sufficiently well matched with a filter arrangement that is analogous to a “2.5” channel parametric equaliser, i.e. two parametric filters and a shelving filter. The first and second channels correspond to two parametric filters that are fully featured and cover the 300 Hz peak at 8 KHz notch. The third channel corresponds to a shelving filter with a frequency and amplitude adjustment only (i.e. no Q). - The amplitude of a parametric equaliser is typically centred around 0 dB, so a separate adjustable gain stage is used to realise the final control or transfer function. In this example around 12 dB of gain is provided by this stage.
- Turning now to
FIG. 3 , a typical circuit to realise the control or transfer function ofFIG. 2 using the parametric equaliser approach is shown. InFIG. 3 , the “ESRC” block provides the overall system gain, the 40 k potentiometers set the channel amplitude, the 1 k adjustable resistors set the channel Q (which determines the bandwidth over which the filter operates) for the peak and the notch, and the frequency of the shelf, the 100 k adjustable resistors set the channel frequency for the peak and the notch. - For integration into an integrated circuit it is typically necessary to have C2 and C3 as external components owing to the low corner frequencies that they realise. For the other capacitors it is possible to integrate them by rescaling (i.e. reducing the capacitor value and increasing the resistor values) whilst still meeting noise floor specifications. The integrated resistors can be realised by a number of means such as “switch cap” or “transconductance”.
- The external component count is therefore only two capacitors (per left or right channel). The adjustable resistor settings can be programmed into the integrated circuit as a one time programmable (OTP) setting.
- In another embodiment one or more parameters of one or more of the filters is dynamically adjustable. Therefore, the adjustable resistor settings for the embodiment shown in
FIG. 3 may be reprogrammable settings permitting dynamic adjustment or change of control law transfer functions.FIG. 4 shows a system according to an embodiment of the invention in which the control law transfer function is realised by acontroller 3 incorporating a plurality of filters (such as the arrangement shown inFIG. 3 ), at least one of the filters having an adjustable parameter. TheFIG. 4 embodiment includes a dynamicperformance adjustment controller 4 which sensing the noise cancellation performance of the apparatus comprising the system by monitoring the noise signal detected by thesensing microphone 2 and sends the necessary signals or instructions to thecontroller 3 to dynamically adjust one or more adjustable parameters of one or more of the filters that realise the control law transfer function. In one embodiment theadjustment controller 4 includes a digital signal processor which periodically monitors the signal fromnoise sensing microphone 2 and determines which parameters of thecontroller 3 require adjustment. Appropriate output signals (either analog or digital) are generated and provided to thecontroller 3 to make the required adjustment. The sensing microphone signal can then be used again to determine whether the adjustment is successful, and to what extent further adjustment is required. - As mentioned above, the invention may be used in association with an active noise cancellation device such as an active noise cancelling headset or earphone. In some embodiments the filters may be part of the device. In others, the filters may be remotely associated with the device, for example being provided in a remote control module. It will be seen that the invention allows continual or periodic monitoring of one or more acoustic or electro-acoustic characteristics of the active noise cancelling device so that the filter(s) can be adjusted to realise a control law transfer function dependent on the determined characteristic(s).
- Similarly, the invention allows a generic filter circuit to be used which can be adjusted for different models or forms of active noise cancelling device. Furthermore, the invention may allow each specific device produced from a production line to be tested for one or more acoustic or electro-acoustic characteristics, so that the control law transfer function for each specific device may be adjusted to optimise performance of that device to account for manufacturing tolerances.
- From the foregoing it will be seen that a solution is proposed which addresses the major limitations of the classical analog realisation of a control law transfer function. In particular, the invention provides an adjustable transfer function that is amenable to integration with a low external part count.
- Those skilled in the art to which the invention relates will appreciate that the invention offers an elegant and viable alternative to a digital control law transfer function realisation. A digital realisation has the disadvantages of requiring high speed, low latency analog to digital and digital to analog conversion as well as the digital signal processing elements. This all comes at a cost in terms of power consumption, noise floor and price amongst others.
- Those skilled in the art will also appreciate that the invention may equally be employed on a digital platform.
Claims (10)
1. Apparatus for realising an active noise cancellation control law transfer function between a sensing microphone and a speaker, the apparatus including a plurality of filters, each filter being operable over a different frequency range, and at least one filter having at least one adjustable parameter whereby the filter can be adjusted such that the filters cumulatively realise a required control law transfer function.
2. Apparatus as claimed in claim 1 wherein each filter includes at least one adjustable parameter.
3. Apparatus as claimed in claim 2 wherein the adjustable parameter is amplitude.
4. Apparatus as claimed in claim 2 wherein the adjustable parameter is bandwidth.
5. Apparatus as claimed in claim 1 wherein the adjustable filter comprises a parametric filter.
6. Apparatus as claimed in claim 1 wherein the adjustable parameter is dynamically adjustable.
7. Apparatus as claimed in claim 6 further comprising an adjustment controller to adjust the adjustable parameter.
8. A method of active noise cancellation for apparatus including a speaker and sensing microphone and a plurality of filters, each filter being operable over a different frequency range, and at least one filter having at least one adjustable parameter whereby the filter can be adjusted, the method including:
determining one or more acoustic or electro-acoustic characteristics of the apparatus, and;
adjusting the adjustable parameter dependent on the characteristic such that the filters cumulatively realise a control law transfer function to implement active noise cancellation.
9. A method of active noise cancellation for apparatus including a speaker and sensing microphone and a plurality of filters, each filter being operable over a different frequency range, and at least one filter having at least one adjustable parameter whereby the filter can be adjusted, the method including:
sensing the noise cancellation performance of the apparatus, and;
adjusting the adjustable parameter dependent on the sensed performance such that the filters cumulatively realise a control law transfer function to implement active noise cancellation.
10. A method as claimed in claim 9 further comprising dynamically adjusting the adjustable parameter.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/812,543 US20180322859A1 (en) | 2009-11-30 | 2017-11-14 | Realisation of controller transfer function for active noise cancellation |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US26499509P | 2009-11-30 | 2009-11-30 | |
US12/956,200 US9818394B2 (en) | 2009-11-30 | 2010-11-30 | Realisation of controller transfer function for active noise cancellation |
US15/812,543 US20180322859A1 (en) | 2009-11-30 | 2017-11-14 | Realisation of controller transfer function for active noise cancellation |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/956,200 Continuation US9818394B2 (en) | 2009-11-30 | 2010-11-30 | Realisation of controller transfer function for active noise cancellation |
Publications (1)
Publication Number | Publication Date |
---|---|
US20180322859A1 true US20180322859A1 (en) | 2018-11-08 |
Family
ID=44505266
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/956,200 Active 2031-05-28 US9818394B2 (en) | 2009-11-30 | 2010-11-30 | Realisation of controller transfer function for active noise cancellation |
US15/812,543 Abandoned US20180322859A1 (en) | 2009-11-30 | 2017-11-14 | Realisation of controller transfer function for active noise cancellation |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/956,200 Active 2031-05-28 US9818394B2 (en) | 2009-11-30 | 2010-11-30 | Realisation of controller transfer function for active noise cancellation |
Country Status (1)
Country | Link |
---|---|
US (2) | US9818394B2 (en) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2584558B1 (en) | 2011-10-21 | 2022-06-15 | Harman Becker Automotive Systems GmbH | Active noise reduction |
EP2667379B1 (en) | 2012-05-21 | 2018-07-25 | Harman Becker Automotive Systems GmbH | Active noise reduction |
US10325584B2 (en) | 2014-12-10 | 2019-06-18 | Stmicroelectronics S.R.L. | Active noise cancelling device and method of actively cancelling acoustic noise |
US20170047059A1 (en) * | 2015-08-11 | 2017-02-16 | Hit Incorporated | Portable hearing test apparatus |
US11153684B2 (en) * | 2018-11-15 | 2021-10-19 | Maxim Integrated Products, Inc. | Dynamic debuzzer for speakers |
US10951974B2 (en) | 2019-02-14 | 2021-03-16 | David Clark Company Incorporated | Apparatus and method for automatic shutoff of aviation headsets |
JP2024510224A (en) * | 2022-02-08 | 2024-03-06 | シェンチェン ショックス カンパニー リミテッド | Active noise canceling audio device, active noise canceling method and storage medium |
Family Cites Families (118)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1368307A (en) * | 1918-04-13 | 1921-02-15 | Western Electric Co | Earpiece |
US1498727A (en) * | 1923-04-07 | 1924-06-24 | Haskel Fred | Removable ear-cushion for telephones |
US1514152A (en) * | 1923-12-28 | 1924-11-04 | Gernsback Hugo | Ear cushion |
US1586140A (en) * | 1924-12-09 | 1926-05-25 | Ralph W S Bonnette | Receiver for radio and telephone apparatus |
US1807225A (en) * | 1928-03-09 | 1931-05-26 | Utah Radio Products Company In | Sound propagating diaphragm |
US2346395A (en) * | 1942-05-04 | 1944-04-11 | Rca Corp | Sound pickup device |
US2379891A (en) * | 1942-10-06 | 1945-07-10 | Bell Telephone Labor Inc | Sound translating device |
US2427844A (en) * | 1942-12-16 | 1947-09-23 | Gylling & Co Ab | Vibratory unit for electrodynamic loud-speakers |
US2490466A (en) * | 1944-07-19 | 1949-12-06 | Rca Corp | Loudspeaker diaphragm support comprising plural compliant members |
US2603724A (en) * | 1948-10-30 | 1952-07-15 | Rca Corp | Sound translating device arranged to eliminate extraneous sound |
US2622159A (en) * | 1950-03-11 | 1952-12-16 | Sydney K Herman | Ear pad for earpieces |
US2714134A (en) * | 1951-02-27 | 1955-07-26 | Martin L Touger | Headset receiver |
US2761912A (en) * | 1951-05-31 | 1956-09-04 | Martin L Touger | Sound translating apparatus |
US2972018A (en) * | 1953-11-30 | 1961-02-14 | Rca Corp | Noise reduction system |
US2775309A (en) * | 1954-03-15 | 1956-12-25 | Acoustic Res Inc | Sound translating devices |
US2848560A (en) * | 1954-09-20 | 1958-08-19 | Beltone Hearing Aid Company | Hearing aid receiver |
USRE26030E (en) * | 1956-02-28 | 1966-05-24 | Dynamic transducer | |
US3112005A (en) * | 1960-07-28 | 1963-11-26 | Ca Nat Research Council | Earphones |
NL257376A (en) * | 1959-10-29 | |||
US2989598A (en) * | 1960-02-24 | 1961-06-20 | Martin L Touger | Hard shell liquid seal earmuff with isolated inner close coupling ear shell |
US3367040A (en) * | 1964-06-05 | 1968-02-06 | A J Ind Inc | Automobile drier unit with muffler means and selectively operable air diverting means |
US3403235A (en) * | 1965-03-17 | 1968-09-24 | Newmarkets Inc | Wide-range loudspeaker |
US3727004A (en) * | 1967-12-04 | 1973-04-10 | Bose Corp | Loudspeaker system |
US3532837A (en) * | 1967-12-19 | 1970-10-06 | Ibm | Headset featuring collapsibility for storage |
US3602329A (en) * | 1970-01-07 | 1971-08-31 | Columbia Broadcasting Systems | Conformal ear enclosure |
US3644939A (en) * | 1970-10-12 | 1972-02-29 | American Optical Corp | Air damped hearing protector earseal |
US3766332A (en) * | 1971-05-17 | 1973-10-16 | Industrial Res Prod Inc | Electroacoustic transducer |
SE377025B (en) | 1972-01-10 | 1975-06-16 | Northern Electric Co | |
DE2329851C2 (en) * | 1973-06-12 | 1975-08-14 | Neckermann Versand Kgaa, 6000 Frankfurt | Headphones for the playback of real quadrophonically recorded information |
US4005267A (en) * | 1974-05-17 | 1977-01-25 | Akg Akustische U. Kino-Gerate Gesellschaft M.B.H. | Arrangement for converting oscillations in headphones |
CA1032479A (en) * | 1974-09-16 | 1978-06-06 | Rudolf Gorike | Headphone |
JPS5162819U (en) * | 1974-11-13 | 1976-05-18 | ||
DE2461278B2 (en) * | 1974-12-23 | 1976-12-16 | Foster Electric Co., Ltd., Tokio | ELECTROACOUSTIC CONVERTER |
US4006318A (en) * | 1975-04-21 | 1977-02-01 | Dyna Magnetic Devices, Inc. | Inertial microphone system |
JPS51129217A (en) * | 1975-05-06 | 1976-11-10 | Victor Co Of Japan Ltd | Headphone |
US4058688A (en) * | 1975-05-27 | 1977-11-15 | Matsushita Electric Industrial Co., Ltd. | Headphone |
AT355646B (en) * | 1977-02-02 | 1980-03-10 | Akg Akustische Kino Geraete | HEADPHONES FOR IMPROVED SPATIAL HEARINGS |
US4211898A (en) * | 1977-07-11 | 1980-07-08 | Matsushita Electric Industrial Co., Ltd. | Headphone with two resonant peaks for simulating loudspeaker reproduction |
US4156118A (en) * | 1978-04-10 | 1979-05-22 | Hargrave Frances E | Audiometric headset |
AT361555B (en) * | 1979-02-12 | 1981-03-25 | Akg Akustische Kino Geraete | HEADPHONE |
US4297537A (en) * | 1979-07-16 | 1981-10-27 | Babb Burton A | Dynamic loudspeaker |
US4581496A (en) * | 1979-09-04 | 1986-04-08 | Emhart Industries, Inc. | Diaphragm for attenuating harmonic response in an electroacoustic transducer |
US4347405A (en) * | 1979-09-06 | 1982-08-31 | Cbs Inc. | Sound reproducing systems utilizing acoustic processing unit |
JPS6042558Y2 (en) | 1980-04-17 | 1985-12-27 | ソニー株式会社 | speaker |
GB2082020B (en) * | 1980-06-30 | 1985-05-30 | Pioneer Electronic Corp | Ear speaker |
JPS6329616Y2 (en) * | 1980-12-26 | 1988-08-09 | ||
US4603724A (en) * | 1980-12-29 | 1986-08-05 | Borwick Innovations, Inc. | Pet door for a screen |
ZA825676B (en) * | 1981-08-11 | 1983-06-29 | Sound Attenuators Ltd | Method and apparatus for low frequency active attennuation |
US4528689A (en) * | 1981-09-22 | 1985-07-09 | International Acoustics Incorporated | Sound monitoring apparatus |
US4418248A (en) * | 1981-12-11 | 1983-11-29 | Koss Corporation | Dual element headphone |
US4441576A (en) | 1982-04-19 | 1984-04-10 | Allen Clayton H | Nonlinear passive acoustic filtering |
US4494074A (en) * | 1982-04-28 | 1985-01-15 | Bose Corporation | Feedback control |
US4455675A (en) * | 1982-04-28 | 1984-06-19 | Bose Corporation | Headphoning |
AT377664B (en) * | 1983-05-26 | 1985-04-25 | Akg Akustische Kino Geraete | EAR CUSHION |
DE3512405A1 (en) | 1984-04-06 | 1985-10-31 | Bose Corp., Framingham, Mass. | Circuit arrangement for generating an output signal controlled by a supplied input signal, and headphones |
US4592366A (en) * | 1984-04-16 | 1986-06-03 | Matsushita Electric Works, Ltd. | Automated blood pressure monitoring instrument |
US4529058A (en) * | 1984-09-17 | 1985-07-16 | Emery Earl L | Earphones |
JPH0733508Y2 (en) * | 1984-10-31 | 1995-07-31 | ソニー株式会社 | earphone |
GB2172470B (en) | 1985-03-16 | 1989-01-11 | Plessey Co Plc | Improvement relating to noise reduction arrangements |
GB8506860D0 (en) | 1985-03-16 | 1985-04-17 | Plessey Co Plc | Noise reduction arrangements |
US4644581A (en) * | 1985-06-27 | 1987-02-17 | Bose Corporation | Headphone with sound pressure sensing means |
US4670733A (en) * | 1985-07-01 | 1987-06-02 | Bell Microsensors, Inc. | Differential pressure transducer |
AT383930B (en) * | 1985-11-18 | 1987-09-10 | Akg Akustische Kino Geraete | EAR PADS FOR HEADPHONES |
JPH0450718Y2 (en) * | 1986-02-28 | 1992-11-30 | ||
GB8607047D0 (en) | 1986-03-21 | 1986-04-30 | Univ Southampton | Acoustic noise reduction |
US4669129A (en) * | 1986-04-07 | 1987-06-02 | Chance Richard L | Earmuff apparatus for use with headsets |
US4852177A (en) * | 1986-08-28 | 1989-07-25 | Sensesonics, Inc. | High fidelity earphone and hearing aid |
NL8602451A (en) * | 1986-09-29 | 1988-04-18 | Philips Nv | SPEAKER WITH A TWO-PIECE MEMBRANE FOR USE AS A CAR SPEAKER. |
NZ225001A (en) * | 1987-06-16 | 1990-09-26 | Matsushita Electric Ind Co Ltd | Loudspeaker: reflected sound waves absorbed |
US4922542A (en) * | 1987-12-28 | 1990-05-01 | Roman Sapiejewski | Headphone comfort |
US5181252A (en) * | 1987-12-28 | 1993-01-19 | Bose Corporation | High compliance headphone driving |
US4905322A (en) * | 1988-04-18 | 1990-03-06 | Gentex Corporation | Energy-absorbing earcup assembly |
US4985925A (en) * | 1988-06-24 | 1991-01-15 | Sensor Electronics, Inc. | Active noise reduction system |
US4949806A (en) * | 1988-12-20 | 1990-08-21 | Stanton Magnetics, Inc. | Headset for underwater use |
US5020163A (en) * | 1989-06-29 | 1991-06-04 | Gentex Corporation | Earseal for sound-attenuating earcup assembly |
GB2234882B (en) | 1989-08-03 | 1994-01-12 | Plessey Co Plc | Noise reduction system |
US5001763A (en) * | 1989-08-10 | 1991-03-19 | Mnc Inc. | Electroacoustic device for hearing needs including noise cancellation |
US5134659A (en) * | 1990-07-10 | 1992-07-28 | Mnc, Inc. | Method and apparatus for performing noise cancelling and headphoning |
US5117461A (en) * | 1989-08-10 | 1992-05-26 | Mnc, Inc. | Electroacoustic device for hearing needs including noise cancellation |
CA2023142A1 (en) | 1989-08-23 | 1991-02-24 | Roman Sapiejewski | High compliance headphone driving |
US4989271A (en) * | 1989-08-24 | 1991-02-05 | Bose Corporation | Headphone cushioning |
US5305387A (en) * | 1989-10-27 | 1994-04-19 | Bose Corporation | Earphoning |
GB9003938D0 (en) | 1990-02-21 | 1990-04-18 | Ross Colin F | Noise reducing system |
US5182774A (en) * | 1990-07-20 | 1993-01-26 | Telex Communications, Inc. | Noise cancellation headset |
WO1992005538A1 (en) * | 1990-09-14 | 1992-04-02 | Chris Todter | Noise cancelling systems |
US5208868A (en) * | 1991-03-06 | 1993-05-04 | Bose Corporation | Headphone overpressure and click reducing |
JP2814772B2 (en) | 1991-05-16 | 1998-10-27 | ソニー株式会社 | Earbud headphones |
US5267321A (en) * | 1991-11-19 | 1993-11-30 | Edwin Langberg | Active sound absorber |
US5343523A (en) | 1992-08-03 | 1994-08-30 | At&T Bell Laboratories | Telephone headset structure for reducing ambient noise |
US5732143A (en) * | 1992-10-29 | 1998-03-24 | Andrea Electronics Corp. | Noise cancellation apparatus |
AU7355594A (en) | 1993-06-23 | 1995-01-17 | Noise Cancellation Technologies, Inc. | Variable gain active noise cancellation system with improved residual noise sensing |
US7103188B1 (en) * | 1993-06-23 | 2006-09-05 | Owen Jones | Variable gain active noise cancelling system with improved residual noise sensing |
US5440642A (en) | 1993-09-20 | 1995-08-08 | Denenberg; Jeffrey N. | Analog noise cancellation system using digital optimizing of variable parameters |
WO1995008907A1 (en) | 1993-09-20 | 1995-03-30 | Noise Cancellation Technologies, Inc. | Optimum headset and method of adjusting same |
CN1050962C (en) | 1993-09-29 | 2000-03-29 | 黄大伟 | Anti-noise earphone |
US5497426A (en) * | 1993-11-15 | 1996-03-05 | Jay; Gregory D. | Stethoscopic system for high-noise environments |
US5504281A (en) * | 1994-01-21 | 1996-04-02 | Minnesota Mining And Manufacturing Company | Perforated acoustical attenuators |
US5604813A (en) * | 1994-05-02 | 1997-02-18 | Noise Cancellation Technologies, Inc. | Industrial headset |
US5652799A (en) * | 1994-06-06 | 1997-07-29 | Noise Cancellation Technologies, Inc. | Noise reducing system |
US6567525B1 (en) | 1994-06-17 | 2003-05-20 | Bose Corporation | Supra aural active noise reduction headphones |
JPH0879878A (en) * | 1994-09-05 | 1996-03-22 | Sony Corp | Headphone device |
SE505203C2 (en) * | 1995-02-01 | 1997-07-14 | Bilsom Ab | A method for changing the sound attenuation of an earmuff as well as the earmuff according to the method |
US5675658A (en) * | 1995-07-27 | 1997-10-07 | Brittain; Thomas Paige | Active noise reduction headset |
US6163615A (en) * | 1997-08-06 | 2000-12-19 | University Research & Engineers & Associates, Inc. | Circumaural ear cup audio seal for use in connection with a headset, ear defender, helmet and the like |
SE507884C2 (en) * | 1996-05-03 | 1998-07-27 | Ericsson Telefon Ab L M | Device and method for sound recording in a speech communicator |
US5740257A (en) * | 1996-12-19 | 1998-04-14 | Lucent Technologies Inc. | Active noise control earpiece being compatible with magnetic coupled hearing aids |
US20010050993A1 (en) | 1997-03-19 | 2001-12-13 | Andrea Douglas | Active noise reduction apparatus having a headset with dual stereo jacks and an electronic device having switch means |
CN1190993C (en) * | 1997-04-17 | 2005-02-23 | 伯斯有限公司 | Acoustic noise reducing |
WO1999005998A1 (en) * | 1997-07-29 | 1999-02-11 | Telex Communications, Inc. | Active noise cancellation aircraft headset system |
CN1087243C (en) | 1997-10-07 | 2002-07-10 | 财团法人工业技术研究院 | Automotive anti-theft devide applying FM sub-carrier and difference correcting satellite positioning tech. |
US6597792B1 (en) * | 1999-07-15 | 2003-07-22 | Bose Corporation | Headset noise reducing |
US7171010B2 (en) * | 2003-09-11 | 2007-01-30 | Boston Acoustics, Inc. | Dynamic bass boost apparatus and method |
US7676048B2 (en) * | 2004-05-14 | 2010-03-09 | Texas Instruments Incorporated | Graphic equalizers |
US7831645B1 (en) * | 2004-10-08 | 2010-11-09 | Kind Of Loud Technologies, Llc | Digital resonant shelf filter |
US7248705B1 (en) * | 2005-12-29 | 2007-07-24 | Van Hauser Llc | Noise reducing headphones with sound conditioning |
EP1858295B1 (en) * | 2006-05-19 | 2013-06-26 | Nuance Communications, Inc. | Equalization in acoustic signal processing |
GB2445984B (en) | 2007-01-25 | 2011-12-07 | Sonaptic Ltd | Ambient noise reduction |
EP2182510B2 (en) | 2008-10-31 | 2016-09-28 | Austriamicrosystems AG | Active noise control arrangement, active noise control headphone and calibration method |
-
2010
- 2010-11-30 US US12/956,200 patent/US9818394B2/en active Active
-
2017
- 2017-11-14 US US15/812,543 patent/US20180322859A1/en not_active Abandoned
Also Published As
Publication number | Publication date |
---|---|
US20110211707A1 (en) | 2011-09-01 |
US9818394B2 (en) | 2017-11-14 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20180322859A1 (en) | Realisation of controller transfer function for active noise cancellation | |
CN111133505B (en) | Parallel Active Noise Reduction (ANR) and traversing listening signal flow paths in acoustic devices | |
JP4523212B2 (en) | Hearing aid with adaptive microphone matching | |
EP2182510B2 (en) | Active noise control arrangement, active noise control headphone and calibration method | |
JP6190501B2 (en) | Active noise reduction | |
EP3660835B1 (en) | Method for tuning a noise cancellation enabled audio system and noise cancellation enabled audio system | |
CN106797513A (en) | The noise of automatic calibration eliminates headphone | |
WO2009081192A1 (en) | Active noise cancellation system with slow rate adaptation of adaptive filter | |
GB2465064A (en) | Active noise cancellation system with split digital filter | |
DK152869B (en) | DEVICE FOR COMPENSATION OF HEAR DAMAGE | |
US10013965B2 (en) | Calibration system for active noise cancellation and speaker apparatus | |
JP2001218298A (en) | Digital hearing device, and its method and system | |
US11062687B2 (en) | Compensation for microphone roll-off variation in acoustic devices | |
US11871193B2 (en) | Microphone system | |
US7822212B2 (en) | Method and system for amplifying auditory sounds | |
US20170127171A1 (en) | Noise reduction system | |
KR101730386B1 (en) | Apparatus and processing method for attenuating noise at sound signal inputted from one microphone | |
US20100061563A1 (en) | Entertainment system and earphone | |
EP4304201A1 (en) | Audio device with anc and hear-through | |
US8385571B2 (en) | Circuit for operating a hearing device and hearing device | |
US20180098159A1 (en) | In-ear microphone | |
US20080123881A1 (en) | Circuit arrangement for adjusting the output power and/or the frequency response of a power amplifier for a hearing aid device | |
JPH02228195A (en) | Headphone device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |