The present invention relates to the field of Adaptive Noise Cancellation (ANC) systems. In particular, the present invention is directed toward a metric and tool to evaluate secondary path design in adaptive noise cancellation systems to improve performance of adaptive noise cancellation systems.
A personal audio device, such as a wireless telephone, includes an adaptive noise canceling (ANC) circuit that adaptively generates an anti-noise signal from a reference microphone signal and injects the anti-noise signal into the speaker or other transducer output to cause cancellation of ambient audio sounds. An error microphone is also provided proximate the speaker to measure the ambient sounds and transducer output near the transducer, thus providing an indication of the effectiveness of the noise canceling. A processing circuit uses the reference and/or error microphone, optionally along with a microphone provided for capturing near-end speech, to determine whether the ANC circuit is incorrectly adapting or may incorrectly adapt to the instant acoustic environment and/or whether the anti-noise signal may be incorrect and/or disruptive and then take action in the processing circuit to prevent or remedy such conditions.
Examples of such Adaptive Noise Cancellation systems are disclosed in published U.S. Patent Application 2012/0140943, published on Jun. 7, 2012, and also in Published U.S. Patent Application 2012/0207317, published on Aug. 16, 2012, both of which are incorporated herein by reference. Both of these references are assigned to the same assignee as the present application and name at least one inventor in common and thus are not “Prior Art” to the present application, but are discussed herein to facilitate the understating of ANC circuits as applied in the field of use.
Referring now to
Wireless telephone 10 includes a transducer, such as speaker SPKR that reproduces distant speech received by wireless telephone 10, along with other local audio events such as ring tones, stored audio program material, injection of near-end speech (i.e., the speech of the user of wireless telephone 10) to provide a balanced conversational perception, and other audio that requires reproduction by wireless telephone 10, such as sources from web-pages or other network communications received by wireless telephone 10 and audio indications such as battery low and other system event notifications. A near-speech microphone NS is provided to capture near-end speech, which is transmitted from wireless telephone 10 to the other conversation participant(s).
Wireless telephone 10 includes adaptive noise canceling (ANC) circuits and features that inject an anti-noise signal into speaker SPKR to improve intelligibility of the distant speech and other audio reproduced by speaker SPKR. A reference microphone R is provided for measuring the ambient acoustic environment, and is positioned away from the typical position of a user's mouth, so that the near-end speech is minimized in the signal produced by reference microphone R. A third microphone, error microphone E, is provided in order to further improve the ANC operation by providing a measure of the ambient audio combined with the audio reproduced by speaker SPKR close to ear pinna 5, when wireless telephone 10 is in close proximity to ear pinna 5. Exemplary circuit 14 within wireless telephone 10 includes an audio CODEC integrated circuit 20 that receives the signals from reference microphone R, near speech microphone NS and error microphone E and interfaces with other integrated circuits such as an RF integrated circuit 12 containing the wireless telephone transceiver. CODEC 20 may incorporate ANC circuitry to provide adaptive noise cancellation.
In general, ANC techniques measure ambient acoustic events (as opposed to the output of speaker SPKR and/or the near-end speech) impinging on reference microphone R, and also measures the same ambient acoustic events impinging on error microphone E. The ANC processing circuits of illustrated wireless telephone 10 adapt an anti-noise signal generated from the output of reference microphone R to have a characteristic that minimizes the amplitude of the ambient acoustic events at error microphone E.
Since acoustic path P(z) (also referred to as the Passive Forward Path) extends from reference microphone R to error microphone E, the ANC circuits are essentially estimating acoustic path P(z) combined with removing effects of an electro-acoustic path S(z) (also referred to as Secondary Path) that represents the response of the audio output circuits of CODEC IC 20 and the acoustic/electric transfer function of speaker SPKR including the coupling between speaker SPKR and error microphone E in the particular acoustic environment, which is affected by the proximity and structure of ear pinna 5 and other physical objects and human head structures that may be in proximity to wireless telephone 10, by the proximity and structure of ear pinna 5 and other physical objects and human head structures that may be in proximity to wireless telephone 10, and how firm the wireless telephone is pressed to ear pinna 5.
Input to the device is from reference microphone R, which outputs signal x(n) which represent the source of acoustic noise recorded by the reference microphone. The transfer function between the reference and error microphones is known as the Primary path P(z) or the passive forward path between error microphone E and the reference microphone R. Primary Path P(z) is represented in block 210. The noise signal after passing through P(z) is called d(n) which also represents the auto output received by error microphone E.
Secondary path S(z) is represented by block 230 and represents the transfer function of the electrical path, including the microphones E, R, and NS, digital circuitry (of
SE(z) in block 280 represents an estimate of S(z). Due to the delay characteristics of the primary and secondary paths P(z), S(z), the feed-forward system of
Predictive filter SE(z), that is shown as block 280, then accepts the input x(n) and uses the output through Least Means Squared filter 270 to create anti-noise filter value W(z) for anti-noise filter 260
The transfer function between the reference and error microphones is known as the Primary path P(z) or the passive forward path between error microphone E and the reference microphone R. The noise signal after passing through P(z) is called d(n).
Block 230 represents transfer function S(z) or the secondary path, which comprises the combined transfer functions of (a) a D/A converter, (b) a power amplifier, (c) speaker SPKR, (d) the air gap between speaker SPKR and error microphone E, (e) error microphone E itself, (f) an A/D converter, and (g) the physical structure of the audio device.
The ANC includes an adaptive filter (not shown) which receives reference microphone signal x(n), and under ideal circumstances, adapts its transfer function W(z) to be a ration of the primary path and secondary path (e.g., P(z)/S(z)) to generate the anti-noise signal. The coefficients of the adaptive filter 260 are controlled by a W(z) coefficient control block 260 that uses a correlation of two signals to determine the response of the adaptive filter, which generally minimizes, in a least-mean squares sense, those components of reference microphone signal x(n) that are present in error microphone signal.
The signals provided as inputs to LMS block 270 are the reference microphone signal x(n) as shaped by a copy of an estimate of the response of path S(z) provided by filter 280 and another signal provided from the output of a combiner 225 that includes the error microphone signal. By transforming reference microphone signal x(n) with a copy of the estimate of the response of path S(z),SE(z), and minimizing the portion of the error signal that correlates with components of reference microphone signal ref, adaptive filter 32 adapts to the desired response of P(z)/S(z).
One problem encountered in designing an adaptive noise cancellation system for a cellular telephone or other device is that the performance of an ANC system is very much dependent on the secondary path structure S(z). The secondary path contains the transfer functions of the D/A converter(s) and power amplifiers within integrated circuit 14, as well as the speaker, the air gap between the speaker and error microphone, the error microphone, A/D converter(s) within the integrated circuit 14, as well as the physical structure of the wireless telephone 10 itself.
Thus, in the prior art, a phone designer (or designer of other audio device) might place microphones and the speaker on the device based on aesthetic design criteria, or based on assumptions as to what would be a good location for a microphone or speaker. Only by building a testing model of the device could the designer evaluate the microphone and speaker placements. At that stage, it may be difficult to change the design if the microphone and speaker placements are found to be less than optimal. Moreover, testing each microphone and speaker combination and placement may be time consuming, particularly in terms of data acquisition and processing. Comparing different combinations of microphones and speakers and their placement, as well as phone case design and other secondary path variables may be difficult, as some combinations may provide superior performance in one frequency range, while others may provide better performance in other frequency ranges.
The inherent delay in the non-minimum phase S(z) is the major bottleneck which forces W(z) to be a predictor. This delay is mainly produced by the speaker transfer function and the air gap which corresponds to the relative placement of the speaker SPKR and the error microphone E. As a result, some of the zeros of S(z) fall outside the unit circle and make S(z) non-invertible. As transfer function W(z) is causal, if there is more delay, then the worse the performance of ANC system becomes. The physical structure and design of the audio system alter the transfer function S(z). There is no single metric that ANC designers and phone makers can use to evaluate the secondary path design (i.e., selection and placement of speaker and microphones, as well as the physical structure and design of the audio device).
Thus, it remains a requirement in the art to provide a metric and tool to evaluate secondary path design in an adaptive noise cancellation system, to allow designers to improve the design of such audio devices, and compare different designs more easily.
The present invention provides a system and method encompassing a new metric and MATLAB toolbox that phone makers may use to improve the design of the secondary path, in order to improve ANC performance. The metric measures how invertible the secondary path is and then evaluates ANC performance at a worst-case scenario where P(z)=1 and W(z) becomes a complete predictor. The invention can be easily extended to a multi-channel ANC system.
A Causal Wiener solution can be calculated as the Least Means Squared (LMS) filter moves toward W0 as the optimal causal Wiener solution, according to equation (1) below, where Ambient noise Power Spectral Density (PSD) is determined by equation (2) and S(z) is determined by equation (3):
Γxx(z)Γx(z)·Γx(z−1)= (2)
S(z)=SMP(z)·SAP(z) (3)
where SMP(Z) is the minimum phase factor, SAP(z) is the all pass factor and Γxx(z) is the power spectral density. From these equations, it is determined that SAP(z) is the non-minimum phase, and thus has zeros outside the unit circle and has a delay.
The inherent delay in the non-minimum phase S(z) is the major bottleneck which forces transfer function W(z) to be a predictor. This delay is mainly produced by the speaker transfer function and the air gap which corresponds to the relative placement of the speaker SPKR and the error microphone E. As a result, some of the zeros of the transfer function S(z) fall outside the unit circle and make S(z) non-invertible. As transfer function W(z) is causal, if more delay exists in the transfer function S(z) then the worse the performance of ANC system becomes. In the prior art, there is no single metric that ANC designers (phone makers) can use to evaluate a secondary path design, such as selection and placement of speaker and microphones, and altering physical structure and design of audio device.
This quality factor, as will be discussed in more detail in connection with
Phones A, B, C, D, E, F, and G, may represent phones from various manufacturers and various models from the same manufacturer, as tested using the secondary path evaluation system and method. As illustrated in
Testing for various ear shapes and spacing combinations is not worthwhile, as the phone manufacturer has no control as to how the user places the phone or the shape of the user's ear—which changes the nature of the secondary path. One goal of an adaptive noise cancellation system is to adapt or modify the cancellation signal based on these changes in the secondary path. Thus, the standard pinna head 810 is used, to test various phones and models of phones, as well as variations in the designs of these phones (microphone and speaker design and placement, for example) and provide a standardized “head” that may be used to provide a baseline for design comparisons.
Pinna head 810 includes a simulated ear pinna 820, which is designed to mimic the acoustical characteristics of a human ear pinna. Bracket 830 is attached to pinna head 810 to hold the cell phone or other audio device in a fixed and measured relationship to pinna 820. When testing, a technician or engineer may place a cell phone (not shown) into bracket 830 for testing purposes. Since bracket 830 may be fixed to a desired position, a phone may be tested repeatedly, after various modifications are made, in the same position and orientation as previous tests.
One advantage of the secondary path evaluation system and method is that a standard applications test board may be used without significant modification. Thus, the system and method may be provided to a customer for the semiconductor device (e.g., cell phone manufacturer), without incurring significant cost for the manufacturer or the customer.
From the data on screen 1210, an engineer or technician can compare the performance of one cell phone configuration against another by comparing the quality factor of one configuration to another. Rather than have to make extensive calculations as to noise cancellation at various frequencies, and make subjective judgments as to whether noise cancellation at different frequencies are comparable to noise cancellation at other frequencies, the quality factor 1220 provides a direct metric of quality of noise cancellation that can be compared across product lines, manufacturers, and configurations.
Once a particular phone configuration has been tested, the engineer or technician may then reconfigure the phone, for example, by moving the location of the error or reference microphones, or the location of the speaker. Different brands and models of microphones and speakers from different suppliers may be compared, to determine how these changes affect the secondary path performance. Placement and location of microphones and speakers may often be dictated by aesthetic design considerations, and type and model of speaker and microphone may be subject to cost constraints. For an engineer, juggling all of these design criteria is difficult enough, without some way of quickly and easily testing and evaluating such designs. The Quality Factor generated by the secondary path evaluation system and method simplifies this testing procedure, allowing an engineer to optimize his design in less time, at less cost.
The present invention may also be applied to grade a number of transducers in terms of their noise cancellation properties. A particular transducer (e.g., microphone, speaker, or the like) may be applied to a particular configuration of portable device components, and the overall system tested as previously described. Other transducers may then be substituted into the configuration, and the test repeated. Once a number of different transducers have been thus tested, the quality factors may then be compared to show the difference in performance and thus grading of different transducer types, brands, or models. As such, the system and method of the present invention may be applied to test individual components, as well as the overall system.
While the preferred embodiment and various alternative embodiments of the invention have been disclosed and described in detail herein, it may be apparent to those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope thereof.
The present application claims priority from Provisional U.S. Patent Application No. 61/815,281 filed on Apr. 24, 2013, and incorporated herein by reference.
Number | Name | Date | Kind |
---|---|---|---|
4020567 | Webster | May 1977 | A |
4926464 | Schley-May | May 1990 | A |
4998241 | Brox et al. | Mar 1991 | A |
5018202 | Takahashi | May 1991 | A |
5021753 | Chapman | Jun 1991 | A |
5044373 | Northeved et al. | Sep 1991 | A |
5117401 | Feintuch | May 1992 | A |
5251263 | Andrea et al. | Oct 1993 | A |
5278913 | Delfosse et al. | Jan 1994 | A |
5321759 | Yuan | Jun 1994 | A |
5337365 | Hamabe et al. | Aug 1994 | A |
5359662 | Yuan et al. | Oct 1994 | A |
5377276 | Terai et al. | Dec 1994 | A |
5386477 | Popovich et al. | Jan 1995 | A |
5410605 | Sawada et al. | Apr 1995 | A |
5425105 | Lo et al. | Jun 1995 | A |
5445517 | Kondou et al. | Aug 1995 | A |
5465413 | Enge et al. | Nov 1995 | A |
5481615 | Eatwell | Jan 1996 | A |
5548681 | Gleaves et al. | Aug 1996 | A |
5550925 | Hori et al. | Aug 1996 | A |
5559893 | Krokstad et al. | Sep 1996 | A |
5586190 | Trantow et al. | Dec 1996 | A |
5633795 | Popovich | May 1997 | A |
5640450 | Watanabe | Jun 1997 | A |
5668747 | Ohashi | Sep 1997 | A |
5687075 | Stothers | Nov 1997 | A |
5696831 | Inanaga et al. | Dec 1997 | A |
5699437 | Finn | Dec 1997 | A |
5706344 | Finn | Jan 1998 | A |
5740256 | Castello Da Costa et al. | Apr 1998 | A |
5768124 | Stothers et al. | Jun 1998 | A |
5809152 | Nakamura et al. | Sep 1998 | A |
5815582 | Claybaugh et al. | Sep 1998 | A |
5832095 | Daniels | Nov 1998 | A |
5852667 | Pan et al. | Dec 1998 | A |
5909498 | Smith | Jun 1999 | A |
5940519 | Kuo | Aug 1999 | A |
5946391 | Dragwidge et al. | Aug 1999 | A |
5991418 | Kuo | Nov 1999 | A |
6041126 | Terai et al. | Mar 2000 | A |
6118878 | Jones | Sep 2000 | A |
6181801 | Puthuff et al. | Jan 2001 | B1 |
6185300 | Romesburg | Feb 2001 | B1 |
6219427 | Kates et al. | Apr 2001 | B1 |
6278786 | McIntosh | Aug 2001 | B1 |
6282176 | Hemkumar | Aug 2001 | B1 |
6304179 | Lotito et al. | Oct 2001 | B1 |
6317501 | Matsuo | Nov 2001 | B1 |
6418228 | Terai et al. | Jul 2002 | B1 |
6434246 | Kates et al. | Aug 2002 | B1 |
6434247 | Kates et al. | Aug 2002 | B1 |
6445799 | Taenzer et al. | Sep 2002 | B1 |
6522746 | Marchok et al. | Feb 2003 | B1 |
6542436 | Myllyla | Apr 2003 | B1 |
6650701 | Hsiang et al. | Nov 2003 | B1 |
6683960 | Fujii et al. | Jan 2004 | B1 |
6738482 | Jaber | May 2004 | B1 |
6766292 | Chandran | Jul 2004 | B1 |
6768795 | Feltstrom et al. | Jul 2004 | B2 |
6792107 | Tucker et al. | Sep 2004 | B2 |
6850617 | Weigand | Feb 2005 | B1 |
6940982 | Watkins | Sep 2005 | B1 |
7016504 | Shennib | Mar 2006 | B1 |
7058463 | Ruha et al. | Jun 2006 | B1 |
7103188 | Jones | Sep 2006 | B1 |
7110864 | Restrepo et al. | Sep 2006 | B2 |
7181030 | Rasmussen et al. | Feb 2007 | B2 |
7330739 | Somayajula | Feb 2008 | B2 |
7365669 | Melanson | Apr 2008 | B1 |
7368918 | Henson et al. | May 2008 | B2 |
7441173 | Restrepo et al. | Oct 2008 | B2 |
7466838 | Moseley | Dec 2008 | B1 |
7680456 | Muhammad et al. | Mar 2010 | B2 |
7742746 | Xiang et al. | Jun 2010 | B2 |
7742790 | Konchitsky et al. | Jun 2010 | B2 |
7817808 | Konchitsky et al. | Oct 2010 | B2 |
7885417 | Christoph | Feb 2011 | B2 |
7953231 | Ishida | May 2011 | B2 |
8019050 | Mactavish et al. | Sep 2011 | B2 |
8085966 | Amsel | Dec 2011 | B2 |
8107637 | Asada et al. | Jan 2012 | B2 |
8165312 | Clemow | Apr 2012 | B2 |
8165313 | Carreras | Apr 2012 | B2 |
D666169 | Tucker et al. | Aug 2012 | S |
8249262 | Chua et al. | Aug 2012 | B2 |
8251903 | LeBoeuf et al. | Aug 2012 | B2 |
8254589 | Mitsuhata | Aug 2012 | B2 |
8290537 | Lee et al. | Oct 2012 | B2 |
8325934 | Kuo | Dec 2012 | B2 |
8331604 | Saito et al. | Dec 2012 | B2 |
8374358 | Buck et al. | Feb 2013 | B2 |
8379884 | Horibe et al. | Feb 2013 | B2 |
8401200 | Tiscareno et al. | Mar 2013 | B2 |
8442251 | Jensen et al. | May 2013 | B2 |
8526627 | Asao et al. | Sep 2013 | B2 |
8532310 | Gauger, Jr. et al. | Sep 2013 | B2 |
8559661 | Tanghe | Oct 2013 | B2 |
8600085 | Chen et al. | Dec 2013 | B2 |
8775172 | Konchitsky et al. | Jul 2014 | B2 |
8804974 | Melanson | Aug 2014 | B1 |
8831239 | Bakalos | Sep 2014 | B2 |
8842848 | Donaldson et al. | Sep 2014 | B2 |
8848936 | Kwatra et al. | Sep 2014 | B2 |
8855330 | Taenzer | Oct 2014 | B2 |
8907829 | Naderi | Dec 2014 | B1 |
8908877 | Abollahzadeh Milani et al. | Dec 2014 | B2 |
8942976 | Li et al. | Jan 2015 | B2 |
8948407 | Alderson et al. | Feb 2015 | B2 |
8948410 | Van Leest | Feb 2015 | B2 |
8958571 | Kwatra et al. | Feb 2015 | B2 |
8977545 | Zeng et al. | Mar 2015 | B2 |
9066176 | Hendrix et al. | Jun 2015 | B2 |
9071724 | Do et al. | Jun 2015 | B2 |
9076431 | Kamath et al. | Jul 2015 | B2 |
9082391 | Yermeche et al. | Jul 2015 | B2 |
9094744 | Le et al. | Jul 2015 | B1 |
9106989 | Li et al. | Aug 2015 | B2 |
9107010 | Abdollahzadeh Milani et al. | Aug 2015 | B2 |
9129586 | Bajic et al. | Sep 2015 | B2 |
9230532 | Lu et al. | Jan 2016 | B1 |
9264808 | Zhou et al. | Feb 2016 | B2 |
9294836 | Zhou et al. | Mar 2016 | B2 |
20010053228 | Jones | Dec 2001 | A1 |
20020003887 | Zhang et al. | Jan 2002 | A1 |
20030063759 | Brennan et al. | Apr 2003 | A1 |
20030072439 | Gupta | Apr 2003 | A1 |
20030185403 | Sibbald | Oct 2003 | A1 |
20040047464 | Yu et al. | Mar 2004 | A1 |
20040120535 | Woods | Jun 2004 | A1 |
20040165736 | Heatherington et al. | Aug 2004 | A1 |
20040167777 | Heatherington et al. | Aug 2004 | A1 |
20040196992 | Ryan | Oct 2004 | A1 |
20040202333 | Csermak et al. | Oct 2004 | A1 |
20040240677 | Onishi et al. | Dec 2004 | A1 |
20040242160 | Ichikawa et al. | Dec 2004 | A1 |
20040264706 | Ray et al. | Dec 2004 | A1 |
20050004796 | Trump et al. | Jan 2005 | A1 |
20050018862 | Fisher | Jan 2005 | A1 |
20050117754 | Sakawaki | Jun 2005 | A1 |
20050207585 | Christoph | Sep 2005 | A1 |
20050240401 | Ebenezer | Oct 2005 | A1 |
20060013408 | Lee | Jan 2006 | A1 |
20060018460 | McCree | Jan 2006 | A1 |
20060035593 | Leeds | Feb 2006 | A1 |
20060055910 | Lee | Mar 2006 | A1 |
20060069556 | Nadjar et al. | Mar 2006 | A1 |
20060109941 | Keele, Jr. | May 2006 | A1 |
20060153400 | Fujita et al. | Jul 2006 | A1 |
20060159282 | Borsch | Jul 2006 | A1 |
20060161428 | Fouret | Jul 2006 | A1 |
20060251266 | Saunders et al. | Nov 2006 | A1 |
20070030989 | Kates | Feb 2007 | A1 |
20070033029 | Sakawaki | Feb 2007 | A1 |
20070038441 | Inoue et al. | Feb 2007 | A1 |
20070047742 | Taenzer et al. | Mar 2007 | A1 |
20070053524 | Haulick et al. | Mar 2007 | A1 |
20070076896 | Hosaka et al. | Apr 2007 | A1 |
20070154031 | Avendano et al. | Jul 2007 | A1 |
20070208520 | Zhang et al. | Sep 2007 | A1 |
20070258597 | Rasmussen et al. | Nov 2007 | A1 |
20070297620 | Choy | Dec 2007 | A1 |
20080019548 | Avendano | Jan 2008 | A1 |
20080101589 | Horowitz et al. | May 2008 | A1 |
20080107281 | Togami et al. | May 2008 | A1 |
20080144853 | Sommerfeldt et al. | Jun 2008 | A1 |
20080177532 | Greiss et al. | Jul 2008 | A1 |
20080181422 | Christoph | Jul 2008 | A1 |
20080226098 | Haulick et al. | Sep 2008 | A1 |
20080240413 | Mohammad et al. | Oct 2008 | A1 |
20080240455 | Inoue et al. | Oct 2008 | A1 |
20080240457 | Inoue et al. | Oct 2008 | A1 |
20080269926 | Xiang et al. | Oct 2008 | A1 |
20090012783 | Klein | Jan 2009 | A1 |
20090034748 | Sibbald | Feb 2009 | A1 |
20090041260 | Jorgensen et al. | Feb 2009 | A1 |
20090046867 | Clemow | Feb 2009 | A1 |
20090060222 | Jeong et al. | Mar 2009 | A1 |
20090080670 | Solbeck et al. | Mar 2009 | A1 |
20090086990 | Christoph | Apr 2009 | A1 |
20090136057 | Taenzer | May 2009 | A1 |
20090175461 | Nakamura et al. | Jul 2009 | A1 |
20090175466 | Elko et al. | Jul 2009 | A1 |
20090196429 | Ramakrishnan et al. | Aug 2009 | A1 |
20090220107 | Every et al. | Sep 2009 | A1 |
20090238369 | Ramakrishnan et al. | Sep 2009 | A1 |
20090245529 | Asada et al. | Oct 2009 | A1 |
20090254340 | Sun et al. | Oct 2009 | A1 |
20090290718 | Kahn et al. | Nov 2009 | A1 |
20090296965 | Kojima | Dec 2009 | A1 |
20090304200 | Kim et al. | Dec 2009 | A1 |
20090311979 | Husted et al. | Dec 2009 | A1 |
20100002891 | Shiraishi et al. | Jan 2010 | A1 |
20100014683 | Maeda et al. | Jan 2010 | A1 |
20100014685 | Wurm | Jan 2010 | A1 |
20100061564 | Clemow et al. | Mar 2010 | A1 |
20100069114 | Lee et al. | Mar 2010 | A1 |
20100082339 | Konchitsky et al. | Apr 2010 | A1 |
20100098263 | Pan et al. | Apr 2010 | A1 |
20100098265 | Pan et al. | Apr 2010 | A1 |
20100124335 | Wessling et al. | May 2010 | A1 |
20100124336 | Shridhar et al. | May 2010 | A1 |
20100124337 | Wertz et al. | May 2010 | A1 |
20100131269 | Park et al. | May 2010 | A1 |
20100142715 | Goldstein et al. | Jun 2010 | A1 |
20100150367 | Mizuno | Jun 2010 | A1 |
20100158330 | Guissin et al. | Jun 2010 | A1 |
20100166203 | Peissig et al. | Jul 2010 | A1 |
20100166206 | Macours | Jul 2010 | A1 |
20100195838 | Bright | Aug 2010 | A1 |
20100195844 | Christoph et al. | Aug 2010 | A1 |
20100226210 | Kordis et al. | Sep 2010 | A1 |
20100239126 | Grafenberg et al. | Sep 2010 | A1 |
20100246855 | Chen | Sep 2010 | A1 |
20100260345 | Shridhar et al. | Oct 2010 | A1 |
20100266137 | Sibbald et al. | Oct 2010 | A1 |
20100272276 | Carreras et al. | Oct 2010 | A1 |
20100272283 | Carreras et al. | Oct 2010 | A1 |
20100272284 | Joho et al. | Oct 2010 | A1 |
20100274564 | Bakalos et al. | Oct 2010 | A1 |
20100284546 | De Brunner et al. | Nov 2010 | A1 |
20100291891 | Ridgers et al. | Nov 2010 | A1 |
20100296666 | Lin | Nov 2010 | A1 |
20100296668 | Lee et al. | Nov 2010 | A1 |
20100310086 | Magrath et al. | Dec 2010 | A1 |
20100322430 | Isberg | Dec 2010 | A1 |
20110007907 | Park et al. | Jan 2011 | A1 |
20110026724 | Doclo | Feb 2011 | A1 |
20110091047 | Konchitsky et al. | Apr 2011 | A1 |
20110096933 | Eastty | Apr 2011 | A1 |
20110099010 | Zhang | Apr 2011 | A1 |
20110106533 | Yu | May 2011 | A1 |
20110116654 | Chan et al. | May 2011 | A1 |
20110129098 | Delano et al. | Jun 2011 | A1 |
20110130176 | Magrath et al. | Jun 2011 | A1 |
20110142247 | Fellers et al. | Jun 2011 | A1 |
20110144984 | Konchitsky | Jun 2011 | A1 |
20110158419 | Theverapperuma et al. | Jun 2011 | A1 |
20110206214 | Christoph et al. | Aug 2011 | A1 |
20110222698 | Asao et al. | Sep 2011 | A1 |
20110222701 | Donaldson et al. | Sep 2011 | A1 |
20110249826 | Van Leest | Oct 2011 | A1 |
20110288860 | Schevciw et al. | Nov 2011 | A1 |
20110293103 | Park et al. | Dec 2011 | A1 |
20110299695 | Nicholson | Dec 2011 | A1 |
20110305347 | Wurm | Dec 2011 | A1 |
20110317848 | Ivanov et al. | Dec 2011 | A1 |
20120057720 | Van Leest | Mar 2012 | A1 |
20120135787 | Kusunoki et al. | May 2012 | A1 |
20120140917 | Nicholson et al. | Jun 2012 | A1 |
20120140942 | Loeda | Jun 2012 | A1 |
20120140943 | Hendrix et al. | Jun 2012 | A1 |
20120148062 | Scarlett et al. | Jun 2012 | A1 |
20120155666 | Nair | Jun 2012 | A1 |
20120170766 | Alves et al. | Jul 2012 | A1 |
20120179458 | Oh et al. | Jul 2012 | A1 |
20120185524 | Clark | Jul 2012 | A1 |
20120207317 | Abdollahzadeh Milani et al. | Aug 2012 | A1 |
20120215519 | Park et al. | Aug 2012 | A1 |
20120250873 | Bakalos et al. | Oct 2012 | A1 |
20120259626 | Li et al. | Oct 2012 | A1 |
20120263317 | Shin et al. | Oct 2012 | A1 |
20120281850 | Hyatt | Nov 2012 | A1 |
20120300955 | Iseki et al. | Nov 2012 | A1 |
20120300958 | Klemmensen | Nov 2012 | A1 |
20120300960 | Mackay et al. | Nov 2012 | A1 |
20120308021 | Kwatra et al. | Dec 2012 | A1 |
20120308024 | Alderson et al. | Dec 2012 | A1 |
20120308025 | Hendrix et al. | Dec 2012 | A1 |
20120308026 | Kamath et al. | Dec 2012 | A1 |
20120308027 | Kwatra | Dec 2012 | A1 |
20120308028 | Kwatra et al. | Dec 2012 | A1 |
20120310640 | Kwatra et al. | Dec 2012 | A1 |
20120316872 | Stoltz et al. | Dec 2012 | A1 |
20130010982 | Elko et al. | Jan 2013 | A1 |
20130083939 | Fellers et al. | Apr 2013 | A1 |
20130156238 | Birch et al. | Jun 2013 | A1 |
20130195282 | Ohita et al. | Aug 2013 | A1 |
20130243198 | Van Rumpt | Sep 2013 | A1 |
20130243225 | Yokota | Sep 2013 | A1 |
20130259251 | Bakalos | Oct 2013 | A1 |
20130272539 | Kim et al. | Oct 2013 | A1 |
20130287218 | Alderson et al. | Oct 2013 | A1 |
20130287219 | Hendrix et al. | Oct 2013 | A1 |
20130301842 | Hendrix et al. | Nov 2013 | A1 |
20130301846 | Alderson et al. | Nov 2013 | A1 |
20130301847 | Alderson et al. | Nov 2013 | A1 |
20130301848 | Zhou et al. | Nov 2013 | A1 |
20130301849 | Alderson et al. | Nov 2013 | A1 |
20130315403 | Samuelsson | Nov 2013 | A1 |
20130343556 | Bright | Dec 2013 | A1 |
20130343571 | Rayala et al. | Dec 2013 | A1 |
20140016803 | Puskarich | Jan 2014 | A1 |
20140036127 | Pong et al. | Feb 2014 | A1 |
20140044275 | Goldstein et al. | Feb 2014 | A1 |
20140050332 | Nielsen et al. | Feb 2014 | A1 |
20140072134 | Po et al. | Mar 2014 | A1 |
20140086425 | Jensen et al. | Mar 2014 | A1 |
20140126735 | Gauger, Jr. | May 2014 | A1 |
20140146976 | Rundle | May 2014 | A1 |
20140169579 | Azmi | Jun 2014 | A1 |
20140177851 | Kitazawa et al. | Jun 2014 | A1 |
20140177890 | Hojland et al. | Jun 2014 | A1 |
20140211953 | Alderson et al. | Jul 2014 | A1 |
20140270222 | Hendrix et al. | Sep 2014 | A1 |
20140270224 | Zhou et al. | Sep 2014 | A1 |
20140294182 | Axelsson et al. | Oct 2014 | A1 |
20140307887 | Alderson | Oct 2014 | A1 |
20140307888 | Alderson et al. | Oct 2014 | A1 |
20140307890 | Zhou et al. | Oct 2014 | A1 |
20140314244 | Yong | Oct 2014 | A1 |
20140314246 | Hellman | Oct 2014 | A1 |
20140314247 | Zhang | Oct 2014 | A1 |
20140341388 | Goldstein | Nov 2014 | A1 |
20140369517 | Zhou et al. | Dec 2014 | A1 |
20150010403 | Wilson et al. | Jan 2015 | A1 |
20150092953 | Abdollahzadeh Milani et al. | Apr 2015 | A1 |
20150161980 | Alderson et al. | Jun 2015 | A1 |
20150161981 | Kwatra | Jun 2015 | A1 |
20150163592 | Alderson | Jun 2015 | A1 |
20150189434 | Hendrix et al. | Jul 2015 | A1 |
20150256660 | Kaller et al. | Sep 2015 | A1 |
20150256953 | Kwatra et al. | Sep 2015 | A1 |
20150269926 | Alderson et al. | Sep 2015 | A1 |
20150296296 | Lu et al. | Oct 2015 | A1 |
20150365761 | Alderson et al. | Dec 2015 | A1 |
Number | Date | Country |
---|---|---|
101552939 | Oct 2009 | CN |
102011013343 | Sep 2012 | DE |
0412902 | Feb 1991 | EP |
0756407 | Jan 1997 | EP |
0898266 | Feb 1999 | EP |
1691577 | Nov 2005 | EP |
1880699 | Jan 2008 | EP |
1947642 | Jul 2008 | EP |
2133866 | Dec 2009 | EP |
2237573 | Oct 2010 | EP |
2216774 | Aug 2011 | EP |
2395500 | Dec 2011 | EP |
2395501 | Dec 2011 | EP |
2551845 | Jan 2013 | EP |
2401744 | Nov 2004 | GB |
2346657 | Oct 2007 | GB |
2455821 | Jun 2009 | GB |
2455824 | Jun 2009 | GB |
2455828 | Jun 2009 | GB |
2484722 | Apr 2012 | GB |
1512832.5 | Jan 2016 | GB |
1519000.2 | Apr 2016 | GB |
06006246 | Jan 1994 | JP |
H06-186985 | Jul 1994 | JP |
H06232755 | Aug 1994 | JP |
07098592 | Apr 1995 | JP |
07104769 | Apr 1995 | JP |
07240989 | Sep 1995 | JP |
07325588 | Dec 1995 | JP |
H111305783 | Nov 1999 | JP |
2000089770 | Mar 2000 | JP |
2002010355 | Jan 2002 | JP |
2004007107 | Jan 2004 | JP |
2006217542 | Aug 2006 | JP |
2007060644 | Mar 2007 | JP |
2008015046 | Jan 2008 | JP |
2010277025 | Dec 2010 | JP |
2011061449 | Mar 2011 | JP |
9113429 | Sep 1991 | WO |
9911045 | Mar 1999 | WO |
03015074 | Feb 2003 | WO |
WO03015275 | Feb 2003 | WO |
WO2004009007 | Jan 2004 | WO |
WO2004017303 | Feb 2004 | WO |
2006125061 | Nov 2006 | WO |
2006128768 | Dec 2006 | WO |
2007007916 | Jan 2007 | WO |
2007011337 | Jan 2007 | WO |
2007110807 | Oct 2007 | WO |
2007113487 | Nov 2007 | WO |
2009041012 | Apr 2009 | WO |
2009110087 | Sep 2009 | WO |
2010117714 | Oct 2010 | WO |
2010131154 | Nov 2010 | WO |
2012107561 | Aug 2012 | WO |
2012134874 | Oct 2012 | WO |
2013106370 | Jul 2013 | WO |
2014172005 | Oct 2014 | WO |
2014172021 | Oct 2014 | WO |
2015191691 | Oct 2014 | WO |
2015038255 | Mar 2015 | WO |
2015088639 | Jun 2015 | WO |
2015088651 | Jun 2015 | WO |
2015088653 | Jun 2015 | WO |
2015134225 | Sep 2015 | WO |
2015191691 | Dec 2015 | WO |
PCTUS2015066260 | Apr 2016 | WO |
2016100602 | Jun 2016 | WO |
Entry |
---|
Campbell, Mikey, “Apple looking into self-adjusting earbud headphones with noise cancellation tech”, Apple Insider, Jul. 4, 2013, pp. 1-10 (10 pages in pdf), downloaded on May 14, 2014 from http://appleinsider.com/articles/13/07/04/apple-looking-into-self-adjusting-earbud-headphones-with-noise-cancellation-tech. |
Erkelens et al., “Tracking of Nonstationary Noise Based on Data-Driven Recursive Noise Power Estimation”, IEEE Transactions on Audio Speech, and Language Processing, vol. 16, No. 6, Aug. 2008. |
Rao et al., “A Novel Two Stage Single Channle Speech Enhancement Technique”, India Conference (INDICON) 2011 Annual IEEE, IEEE, Dec. 15, 2011. |
Rangachari et al., “A noise-estimation algorithm for highly non-stationary environments” Speech Communication, Elsevier Science Publishers, vol. 48, No. 2, Feb. 1, 2006. |
International Search Report and Written Opinion of the International Searching Authority, International Patent Application No. PCT/US2014/017343, mailed Aug. 8, 2014, 22 pages. |
International Search Report and Written Opinion of the International Searching Authority, International Patent Application No. PCT/US2014/018027, mailed Sep. 4, 2014, 14 pages. |
International Search Report and Written Opinion of the International Searching Authority, International Patent Application No. PCT/US2014/017374, mailed Sep. 8, 2014, 13 pages. |
International Search Report and Written Opinion of the International Searching Authority, International Patent Application No. PCT/US2014/019395, mailed Sep. 9, 2014, 14 pages. |
International Search Report and Written Opinion of the International Searching Authority, International Patent Application No. PCT/US2014/019469, mailed Sep. 12, 2014, 13 pages. |
Feng, Jinwei et al., “A broadband self-tuning active noise equaliser”, Signal Processing, Elsevier Science Publishers B.V. Amsterdam, NL, vol. 62, No. 2, Oct. 1, 1997, pp. 251-256. |
Zhang, Ming et al., “A Robust Online Secondary Path Modeling Method with Auxiliary Noise Power Scheduling Strategy and Norm Constraint Manipulation”, IEEE Transactions on Speech and Audio Processing, IEEE Service Center, New York, NY, vol. 11, No. 1, Jan. 1, 2003. |
Lopez-Gaudana, Edgar et al., “A hybrid active noise cancelling with secondary path modeling”, 51st Midwest Symposium on Circuits and Systems, 2008, MWSCAS 2008, Aug. 10, 2008, pp. 277-280. |
Widrow, B. et al., Adaptive Noise Cancelling; Principles and Applications, Proceedings of the IEEE, IEEE, New York, NY, U.S. vol. 63, No. 13, Dec. 1975, pp. 1692-1716. |
Morgan, Dennis R. et al., A Delayless Subband Adaptive Filter Architecture, IEEE Transactions on Signal Processing, IEEE Service Center, New York, New York. US, vol. 43, No. 8, Aug. 1995, pp. 1819-1829. |
International Search Report and Written Opinion of the International Searching Authority, International Patent Application No. PCT/US2014/040999, mailed Oct. 18, 2014, 12 pages. |
International Search Report and Written Opinion of the International Searching Authority, International Patent Application No. PCT/US2034/049407, mailed Jun. 18, 2914, 13 pages. |
Toochinda, et al. “A Single-Input Two-Output Feedback Formulation for ANC Problems,” Proceedings of the 2001 American Control Conference, Jun. 2001, pp. 923-928, vol. 2, Arlington, VA. |
Kuo, et al., “Active Noise Control: A Tutorial Review,” Proceedings of the IEEE, Jun. 1999, pp. 943-973, vol. 87, No. 6, IEEE Press, Piscataway, NJ. |
Johns, et al., “Continuous-Time LMS Adaptive Recursive Filters,” IEEE Transactions on Circuits and Systems, Jul. 1991, pp. 769-778, vol. 38, No. 7, IEEE Press, Piscataway, NJ. |
Shoval, et al., “Comparison of DC Offset Effects in Four LMS Adaptive Algorithms,” IEEE Transactions on Circuits and Systems II: Analog and Digital Processing, Mar. 1995, pp. 176-185, vol. 42, Issue 3, IEEE Press, Piscataway, NJ. |
Mali, Dilip, “Comparison of DC Offset Effects on LMS Algorithm and its Derivatives,” International Journal of Recent Trends in Engineering, May 2009, pp. 323-328, vol. 1, No. 1, Academy Publisher. |
Kates, James M., “Principles of Digital Dynamic Range Compression,” Trends in Amplification, Spring 2005, pp. 45-76, vol. 9, No. 2, Sage Publications. |
Gao, et al., “Adaptive Linearization of a Loudspeaker,” IEEE International Conference on Acoustics, Speech, and Signal Processing, Apr. 14-17, 1991, pp. 3589-3592, Toronto, Ontario, CA. |
Silva, et al., “Convex Combination of Adaptive Filters With Different Tracking Capabilities,” IEEE International Conference on Acoustics, Speech, and Signal Processing, Apr. 15-20, 2007, pp. III 925-928, vol. 3, Honolulu, HI, USA. |
Akhtar, et al., “A Method for Online Secondary Path Modeling in Active Noise Control Systems,” IEEE International Symposium on Circuits and Systems, May 23-26, 2005, pp. 264-267, vol. 1, Kobe, Japan. |
Davari, et al., “A New Online Secondary Path Modeling Method for Feedforward Active Noise Control Systems,” IEEE International Conference on Industrial Technology, Apr. 21-24, 2008, pp. 1-6, Chengdu, China. |
Lan, et al., “An Active Noise Control System Using Online Secondary Path Modeling With Reduced Auxiliary Noise,” IEEE Signal Processing Letters, Jan. 2002, pp. 16-18, vol. 9, Issue 1, IEEE Press, Piscataway, NJ. |
Liu, et al., “Analysis of Online Secondary Path Modeling With Auxiliary Noise Scaled by Residual Noise Signal,” IEEE Transactions on Audio, Speech and Language Processing, Nov. 2010, pp. 1978-1993, vol. 18, Issue 8, IEEE Press, Piscataway, NJ. |
Pfann, et al., “LMS Adaptive Filtering with Delta-Sigma Modulated Input Signals,” IEEE Signal Processing Letters, Apr. 1998, pp. 95-97, vol. 5, No. 4, IEEE Press, Piscataway, NJ. |
Abdollahzadeh Milani, et al., “On Maximum Achievable Noise Reduction in ANC Systems”,2010 IEEE International Conference on Acoustics Speech and Signal Processing, Mar. 14-19, 2010, pp. 349-352, Dallas, TX, US. |
Ryan, et al., “Optimum Near-Field Performance of Microphone Arrays Subject to a Far-Field Beampattern Constraint”, J. Acoust. Soc. Am., Nov. 2000, pp. 2248-2255, 108 (5), Pt 1, Ottawa, Ontario, Canada. |
Cohen, et al., “Noise Estimation by Minima Controlled Recursive Averaging for Robust Speech Enhancement”, IEEE Signal Processing Letters, vol. 9, No. 1, Jan. 2002. |
Martin, Rainer, “Noise Power Spectral Density Estimation Based on Optimal Smoothing and Minimum Statistics”, IEEE Transactions on Speech and Audio Processing, Jul. 2001, pp. 504-512, vol. 9, No. 5, Piscataway, NJ, US. |
Martin, Rainer, “Spectral Subtraction Based on Minimum Statistics”, Signal Processing VII Theories and Applications, Proceedings of EUSIPCO-94, 7th European Signal Processing Conference, Sep. 13-16, 1994, pp. 1182-1185, vol. III, Edinburgh, Scotland, U.K. |
Cohen, Israel, “Noise Spectrum Estimation in Adverse Environments: Improved Minima Controlled Recursive Averaging”, IEEE Transactions on Speech and Audio Processing, Sep. 2003, pp. 1-11, vol. 11, Issue 5, Piscataway, NJ, US. |
Hurst, et al., “An improved double sampling scheme for switched-capacitor delta-sigma modulators”, 1992 IEEE Int. Symp. on Circuits and Systems, May 10-13, 1992, vol. 3, pp. 1179-1182, San Diego, CA. |
Senderowicz, et al., “Low-Voltage Double-Sampled Delta-Sigma Converters”, IEEE Journal on Solid-State Circuits, Dec. 1997, pp. 1907-1919, vol. 32, No. 12, Piscataway, NJ. |
Lopez-Caudana, Edgar Omar, “Active Noise Cancellation: The Unwanted Signal and the Hybrid Solution”, Adaptive Filtering Application, Dr. Lino Garcia (Ed.), Jul. 2011, pp. 49-84, ISBN: 978-953-307-306-4, InTech. |
Kuo, et al., “Residual noise shaping technique for active noise control systems”, J. Acoust. Soc. Am. 95 (3), Mar. 1994, pp. 1665-1668. |
Booij, et al., “Virtual sensors for local, three dimensional, broadband multiple-channel active noise control and the effects on the quiet zones”, Proceedings of the International Conference on Noise and Vibration Engineering, ISMA 2010, Sep. 20-22, 2010, pp. 151-166, Leuven. |
Black, John W., “An Application of Side-Tone in Subjective Tests of Microphones and Headsets”, Project Report No. NM 001 064.01.20, Research Report of the U.S. Naval School of Aviation Medicine, Feb. 1, 1954, 12 pages (pp. 1-12 in pdf), Pensacola, FL, US. |
Peters, Robert W., “The Effect of High-Pass and Low-Pass Filtering of Side-Tone Upon Speaker Intelligibility”, Project Report No. NM 001 064.01.25, Research Report of the U.S. Naval School of Aviation Medicine, Aug. 16, 1954, 13 pages (pp. 1-13 in pdf), Pensacola, FL, US. |
Lane, et al., “Voice Level: Autophonic Scale, Perceived Loudness, and the Effects of Sidetone”, The Journal of the Acoustical Society of America, Feb. 1961, pp. 160-167, vol. 33, No. 2., Cambridge, MA, US. |
Liu, et al., “Compensatory Responses to Loudness-shifted Voice Feedback During Production of Mandarin Speech”, Journal of the Acoustical Society of America, Oct. 2007, pp. 2405-2412, vol. 122, No. 4. |
Paepcke, et al., “Yelling in the Hall: Using Sidetone to Address a Problem with Mobile Remote Presence Systems”, Symposium on User Interface Software and Technology, Oct. 16-19, 2011, 10 pages (pp. 1-10 in pdf), Santa Barbara, CA, US. |
Therrien, et al., “Sensory Attenuation of Self-Produced Feedback: The Lombard Effect Revisited”, Plos One, Nov. 2012, pp. 1-7, vol. 7, Issue 11, e49370, Ontario, Canada. |
Parkins, et al., “Narrowband and broadband active control in an enclosure using the acoustic energy density”, J. Acoust. Soc. Am. Jul. 2000, pp. 192-203, vol. 108, issue 1, US. |
Rafaely, Boaz, “Active Noise Reducing Headset—an Overview”, The 2001 International Congress and Exhibition on Voise Control Engineering, Aug. 27-30, 2001, 10 pages (pp. 1-10 in pdf), The Netherlands. |
Jin, et al. “A simultaneous equation method-based online secondary path modeling algorithm for active noise control”, Journal of Sound and Vibration, Apr. 25, 2007, pp. 455-474, vol. 303, No. 3-5, London, GB. |
Ray, et al., “Hybrid Feedforward-Feedback Active Noise Reduction for Hearing Protection and Communication”, The Journal of the Acoustical Society of America, American Institute of Physics for the Acoustical Society of America, Jan. 2006, pp. 2026-2036, vol. 120, No. 4, New York, NY. |
Number | Date | Country | |
---|---|---|---|
61815281 | Apr 2013 | US |