EP2629289B1 - Feedback active noise control system with a long secondary path - Google Patents
Feedback active noise control system with a long secondary path Download PDFInfo
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- EP2629289B1 EP2629289B1 EP12155561.9A EP12155561A EP2629289B1 EP 2629289 B1 EP2629289 B1 EP 2629289B1 EP 12155561 A EP12155561 A EP 12155561A EP 2629289 B1 EP2629289 B1 EP 2629289B1
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- 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
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1785—Methods, e.g. algorithms; Devices
- G10K11/17853—Methods, e.g. algorithms; Devices of the filter
- G10K11/17854—Methods, e.g. algorithms; Devices of the filter the filter being an adaptive filter
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
- G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
- G10K11/1785—Methods, e.g. algorithms; Devices
- G10K11/17857—Geometric disposition, e.g. placement of microphones
-
- 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
- G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
- G10K2210/10—Applications
- G10K2210/108—Communication systems, e.g. where useful sound is kept and noise is cancelled
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
- G10K2210/10—Applications
- G10K2210/128—Vehicles
- G10K2210/1282—Automobiles
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- 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
- G10K2210/3011—Single acoustic input
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- 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
- G10K2210/3026—Feedback
Definitions
- the invention relates to a feedback ANC system having a long secondary path and, in particular, to a feedback ANC system applicable in vehicle cabins.
- Active noise control (ANC) systems are, for example, known from the publications JP S60-183900 A , US 2008/240456 A1 , US 2005/207585 A1 , US 5,953,428 , JP H11-305784 A , and US 2010/124337 A1 .
- the publication US 2009/220098 A1 describes an adaptive bass management method for adapting sound pressure levels in at least one listening location.
- JPH0632532B discloses a feedback ANC system for a vehicle in which a useful signal (such as a radio or cassette player sound) is added to the ANC signal output by the ANC loudspeaker, and in which a delayed and adjusted version of the useful signal is subtracted from the error signal prior to feeding it to the ANC flter.
- a useful signal such as a radio or cassette player sound
- a microphone is acoustically coupled to a loudspeaker via a secondary path and the loudspeaker is electrically coupled to the microphone via an electrical ANC filter.
- the ANC filter filters the signal from the microphone such that the signal that it provides to the loudspeaker and that is radiated by the loudspeaker to the microphone via the secondary path cancels the noise signal in the vicinity of the microphone.
- the degree of noise cancellation depends on the quality and stabilitiy of the secondary path and the ANC filter.
- Feedback ANC systems are commonly used in arrangements in which the microphone is arranged relatively close ( ⁇ 0.34 m) to the loudspeaker as, for instance, in ANC headphones and, thus, in connection with very short secondary paths.
- feedback ANC systems are often implemented in analog circuitry and/or as non-adaptive fixed filters so that subsequent adaption to different modes of operation is difficult or even impossible.
- vehicle cabins are relatively large rooms with long distances ( ⁇ 0.34 m) between loudspeaker and microphone.
- different modes of operation with widely varying secondary paths are determined by different passengers, a different number of passengers, open doors and open windows etc.
- Feedback ANC systems are not considered suitable for applications in large rooms and are therefore not suitable for automotive applications.
- Common automotive ANC systems are feedforward systems, such as the so-called engine order compensation (EOC) system or the road noise compensation (RNC) system, that use dedicated non-acoustic sensors and operate in a very limited frequency range.
- EOC engine order compensation
- RNC road noise compensation
- feedback ANC systems in general are less complex, require less circuitry, operate in a broader frequency range and exhibit a better performance.
- a feedback ANC system comprises a microphone and a loudspeaker arranged in a distance from each other.
- the microphone is acoustically coupled to the loudspeaker via a secondary path and the loudspeaker is electrically coupled to the microphone via an ANC filter.
- the distance between the microphone and the loudspeaker is larger than a value that is determined by the speed of sound divided by 20 times an upper critical frequency of the ANC system, and smaller than or equal to a value that is determined by the speed of sound divided by two times an upper critical frequency.
- the system further comprises a first subtractor that is connected downstream of the microphone and a first useful-signal path, wherein the ANC filter is connected downstream of the first subtractor.
- the system also comprises a second subtractor that is connected upstream of the loudspeaker, and connected downstream of the ANC filter and a second useful-signal path. Both useful-signal paths are supplied with a useful signal to be reproduced.
- the second useful-signal path comprises a second spectrum shaping filter that has a transfer characteristic that is equal to the inverse secondary path transfer characteristic.
- FIG. 1 is a block diagram illustrating the principles of signal processing in a feedback ANC system.
- an error microphone 1 is acoustically coupled to a loudspeaker 2 via a secondary path 3 and the loudspeaker 2 is electrically coupled to the microphone 1 via a feedback signal path 4 including a microphone pre-amplifier 5, a subsequent ANC filter 6 with a transfer function W(z) and a subsequent loudspeaker driver amplifier 7 whose amplification A 7 is adjustable or controllable.
- the microphone 1 and the loudspeaker 2 are arranged in a room, e.g., a vehicle cabin 10.
- the term “loudspeaker” as used herein means any type of transducer that converts electrical signals it receives into acoustic signals that it radiates. Accordingly, the term “microphone” as used herein means any type of transducer that converts acoustic signals it receives into electrical signals that it provides.
- the microphone 1 receives an acoustic signal that is composed of an acoustic output signal y(t) and an acoustic disturbance signal d(t).
- Output signal y(t) is the output signal of the loudspeaker 2 filtered with a transfer function S(z) of the secondary path 3 and disturbance signal d(t) is the output signal of a noise source 8 filtered with a transfer function P(z) of a primary path 9.
- FIG. 2 shows a vehicle cabin 10 in which the active noise reduction system of FIG. 1 may be applied.
- the microphone 1 is mounted in the left front portion 11 of the cabin 10, close to a driver's head.
- the loudspeaker 2 e.g., a subwoofer, is mounted on the rear shelf 12 of the cabin 10. The distance d between the microphone 1 and the loudspeaker 2 is approximately 3 m.
- FIG. 3 depicts (a) the magnitude frequency response, (b) the phase frequency response, (c) the sensitivity function and (d) the complementary sensitivity function.
- the magnitude frequency response is the magnitude in dB over frequency in Hz.
- the phase frequency response is the phase in degree over frequency in Hz.
- H OL (z) W(z) ⁇ S(z) is the transfer function of the open loop of the feedback ANC system.
- an analog, non-adaptive ANC filter may be used that comprises one boost and one cut equalizing filter with the following dimensioning:
- FIGS 3c and 3d illustrate the corresponding sensitivity function 17 and the complementary sensitivity function 19, each in connection with the error margin18.
- graphs 20 and 21 depict measurements of the attenuation A [dB] over frequency f [Hz] of the system shown in FIGS. 1 and 2 when the ANC system is not active (20) and when it is active (21). It can readily be seen from graph 25 that a maximum attenuation of approximately 8 dB is reached in exact the spectral range identified in the simulations and that the ANC filter used exhibits the so-called "Waterbed Effect" which describes an increase in attenuation in a certain spectral range typical for ANC systems but which may be considered too large in the present case and, thus, may render the system instable under certain conditions.
- Waterbed Effect describes an increase in attenuation in a certain spectral range typical for ANC systems but which may be considered too large in the present case and, thus, may render the system instable under certain conditions.
- the loop gain LP may be decreased by, e.g., up to 3 dB.
- graph 22 which represents a system with low-pass filtering and inactive ANC
- graph 23 which represents a system with low-pass filtering and active ANC
- the difference of graphs 22 and 23 being about 6 dB and represented by graph 24.
- graphs 20 and 21 show that there is no attenuation by the ANC system at higher frequencies.
- the system disclosed herein allows for distances between the microphone and the loudspeaker larger than a value that is determined by the speed of sound divided by 20 times an upper critical frequency.
- a satisfactory performance may be even achieved, e.g., for distances between the microphone and the loudspeaker that are smaller than or equal to a value that is determined by the speed of sound divided by 2 times an upper critical frequency.
- FIG. 5 shows a multi-zone ANC system with four zones of silent FL, FR, RL and RR that correspond to driver/passenger positions front left, front right, rear left and rear right.
- one of microphones 1 fl , 1 fr , 1 rl , 1 rr and one of loudspeakers 2 fl , 2 fr , 2 rl , 2 rr are arranged in a distance d fl , d fr , d rl , d rr > 0.3 m from each other.
- Each one of microphones 1 fl , 1 fr , 1 rl ,1 rr is connected to a corresponding one of loudspeakers 2 fl , 2 fr , 2 rl , 2 rr via one of ANC filters 6fl, 6fr, 6rl, 6rr which are operated independently of each other.
- the feedback ANC systems described herein are capable of distinguishing between wanted signals, i.e., useful signals such as acoustic warning signals, music and speech, and unwanted signals such as noise.
- useful signals such as acoustic warning signals, music and speech
- unwanted signals such as noise.
- Exemplary circuit structures with specific input paths for the useful signals are described below with reference to FIGS. 6 , 7 and 8 .
- FIG. 6 is a block diagram illustrating a general feedback type active noise reduction system in which the useful signal is supplied to both the loudspeaker path and the microphone path.
- the primary path 9 is omitted below, notwithstanding that noise (disturbing signal d[n]) is still present.
- the system of FIG. 6 is based on the system of FIG. 1 , however with an additional subtractor 26 that subtracts the useful signal x[n] from the microphone output signal y[n] to form the ANC filter input signal, i.e., error signal e[n] and with a subtractor 27 that subtracts the useful signal x[n] from the output signal u[n] of ANC filter 6.
- M z S z ⁇ W z ⁇ S z / 1 ⁇ W z ⁇ S z lim W z ⁇ S z ⁇ 1 M z ⁇ M z ⁇ ⁇ lim W z ⁇ S z ⁇ 0 M z ⁇ M z ⁇ S z lim W z ⁇ S z ⁇ ⁇ ⁇ M z ⁇ M z ⁇ 1 .
- the useful signal transfer characteristic M(z) approaches S(z) when the open loop transfer characteristic (W(z) ⁇ S(z)) approaches 0.
- the system of FIG. 6 depends on the transfer characteristic S(z) of the secondary path 3 and its fluctuations due to aging, temperature, change of listener etc.
- FIG. 7 a system is shown that is based on the system of FIG. 6 and that additionally includes an equalizing filter 28 connected upstream of the subtractor 27 in order to filter the useful signal x[n] with the inverse secondary path transfer function 1/S(z).
- the microphone output signal y[n] is identical to the useful signal x[n], which means that signal x[n] is not altered by the system if the characteristic of the equalizing filter is exactly the inverse of the secondary path transfer characteristic S(z).
- the secondary path transfer function S(z) in a car is generally not minimum-phase, as can be seen, e.g., from the phase frequency response shown FIGS. 3a and 3b, only approximations of its inverse exist. The probably simplest way is to take the minimum-phase version of S(z), since this can be inverted.
- y[z] x[z]
- FIG. 8 a system is shown that is based on the system of FIG. 3 and that additionally includes an equalizing filter 28 connected upstream of the subtractor 26 in order to filter the useful signal x[n] with the secondary path transfer function S(z).
- the useful signal transfer characteristic M(z) is identical with the secondary path transfer characteristic S(Z) when the ANC system is active.
- the useful signal transfer characteristic M(z) is also identical with the secondary path transfer characteristic S(Z).
- the aural impression of the useful signal for a listener at a location close to the microphone 1 is the same regardless of whether noise reduction is active or not. This is the most likely way of considering a useful-signal in terms of an automobile environment, since there the useful-signal is mostly music, which should not be disturbed by an algorithm like the feedback ANC system specified here.
- the thereby needed replica of the secondary path S(z) can, without any problems, be realized in a complex form e.g.
- the ANC filter 6 and the equalizing filters 28 and 29 may be fixed filters with constant transfer characteristics or adaptive filters with controllable transfer characteristics.
- the adaptive structure of a filter per se is indicated by an arrow underlying the respective block and the optionality of the adaptive structure is indicated by a broken line.
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Description
- The invention relates to a feedback ANC system having a long secondary path and, in particular, to a feedback ANC system applicable in vehicle cabins. Active noise control (ANC) systems are, for example, known from the publications
JP S60-183900 A US 2008/240456 A1 ,US 2005/207585 A1 ,US 5,953,428 ,JP H11-305784 A US 2010/124337 A1 . The publicationUS 2009/220098 A1 describes an adaptive bass management method for adapting sound pressure levels in at least one listening location. - Furthermore,
JPH0632532B - In active noise control (ANC) systems of the feedback type, a microphone is acoustically coupled to a loudspeaker via a secondary path and the loudspeaker is electrically coupled to the microphone via an electrical ANC filter. The ANC filter filters the signal from the microphone such that the signal that it provides to the loudspeaker and that is radiated by the loudspeaker to the microphone via the secondary path cancels the noise signal in the vicinity of the microphone. The degree of noise cancellation depends on the quality and stabilitiy of the secondary path and the ANC filter. Feedback ANC systems are commonly used in arrangements in which the microphone is arranged relatively close (< 0.34 m) to the loudspeaker as, for instance, in ANC headphones and, thus, in connection with very short secondary paths. Furthermore, feedback ANC systems are often implemented in analog circuitry and/or as non-adaptive fixed filters so that subsequent adaption to different modes of operation is difficult or even impossible. For instance, vehicle cabins are relatively large rooms with long distances (≥ 0.34 m) between loudspeaker and microphone. Furthermore, different modes of operation with widely varying secondary paths are determined by different passengers, a different number of passengers, open doors and open windows etc.
- Feedback ANC systems are not considered suitable for applications in large rooms and are therefore not suitable for automotive applications. Common automotive ANC systems are feedforward systems, such as the so-called engine order compensation (EOC) system or the road noise compensation (RNC) system, that use dedicated non-acoustic sensors and operate in a very limited frequency range. However, feedback ANC systems in general are less complex, require less circuitry, operate in a broader frequency range and exhibit a better performance.
- There is a need to provide an improved large room feedback ANC system in particular for use in vehicle cabins.
- A feedback ANC system is disclosed herein that comprises a microphone and a loudspeaker arranged in a distance from each other. The microphone is acoustically coupled to the loudspeaker via a secondary path and the loudspeaker is electrically coupled to the microphone via an ANC filter. The distance between the microphone and the loudspeaker is larger than a value that is determined by the speed of sound divided by 20 times an upper critical frequency of the ANC system, and smaller than or equal to a value that is determined by the speed of sound divided by two times an upper critical frequency. The system further comprises a first subtractor that is connected downstream of the microphone and a first useful-signal path, wherein the ANC filter is connected downstream of the first subtractor. The system also comprises a second subtractor that is connected upstream of the loudspeaker, and connected downstream of the ANC filter and a second useful-signal path. Both useful-signal paths are supplied with a useful signal to be reproduced. The second useful-signal path comprises a second spectrum shaping filter that has a transfer characteristic that is equal to the inverse secondary path transfer characteristic.
- Various specific embodiments are described in more detail below based on the exemplary embodiments shown in the figures of the drawings. Unless stated otherwise, similar or identical components are labeled in all of the figures with the same reference numbers.
-
FIG. 1 is a block diagram illustrating the principles of signal processing in a feedback ANC system. -
FIG. 2 is a schematic diagram of a vehicle cabin in which the active noise reduction system ofFIG. 1 may be applied. -
FIG. 3 is a diagram depicting simulation results of the system shown inFIGS. 1 and 2 . -
FIG. 4 is a diagram depicting measurements of the attenuation over frequency of the system shown inFIGS. 1 and 2 when the ANC system is active and inactive. -
FIG. 5 is a schematic diagram illustrating a multi-channel ANC system. -
FIG. 6 is a block diagram of a general feedback type active noise reduction system in which a useful signal is supplied to the loudspeaker and microphone signal paths. -
FIG. 7 is a block diagram of the active noise reduction system ofFIG. 6 , in which the useful signal is supplied via a spectrum shaping filter to the loudspeaker path. -
FIG. 8 is a block diagram of the active noise reduction system ofFIG. 6 , in which the useful signal is supplied via a spectrum shaping filter to the microphone path. - Reference is now made to
FIG. 1 , which is a block diagram illustrating the principles of signal processing in a feedback ANC system. In the ANC system ofFIG. 1 , anerror microphone 1 is acoustically coupled to aloudspeaker 2 via asecondary path 3 and theloudspeaker 2 is electrically coupled to themicrophone 1 via afeedback signal path 4 including a microphone pre-amplifier 5, a subsequent ANCfilter 6 with a transfer function W(z) and a subsequentloudspeaker driver amplifier 7 whose amplification A7 is adjustable or controllable. Themicrophone 1 and theloudspeaker 2 are arranged in a room, e.g., avehicle cabin 10. The term "loudspeaker" as used herein means any type of transducer that converts electrical signals it receives into acoustic signals that it radiates. Accordingly, the term "microphone" as used herein means any type of transducer that converts acoustic signals it receives into electrical signals that it provides. - The
microphone 1 receives an acoustic signal that is composed of an acoustic output signal y(t) and an acoustic disturbance signal d(t). Output signal y(t) is the output signal of theloudspeaker 2 filtered with a transfer function S(z) of thesecondary path 3 and disturbance signal d(t) is the output signal of anoise source 8 filtered with a transfer function P(z) of aprimary path 9. From this received acoustic signal y(t)-d(t) themicrophone 1 generates an electrical error signal e(t) which is amplified by the microphone pre-amplifier 5 and then supplied as amplified error signal e'(t) = A5 e(t) to the subsequent ANCfilter 6. For the sake of simplicity, the amplification A5 of microphone pre-amplifier 5 is assumed to be equal to 1 in the considerations below so that e'(t) = e(t), but may have any other appropriate value if required. The ANC system shown inFIG. 1 can be described by the following differential equations in the spectral domain based on the various signals in the time domain, in which D(z), E(z) and Y(z) are the spectral representations of the signals d(t), e(t) and y(t) in the time domain: - The use of feedback ANC systems in vehicles is widely discussed, e.g., by Stephen Elliott, "Signal Processing", Academic Press, London, 2001, paragraphs 6.5.2 and 6.10. His findings include, inter alia, the following:
- (a) Feedback ANC systems are not capable of distinguishing between wanted signals such as acoustic warning signals, music and speech, and unwanted signals such as noise.
- (b) The maximum attenuation in feedback ANC systems is much more sensitive to the plant delay τ of the systems than it is in feedforward ANC systems. Therefore, the plant delay of feedback ANC systems should be kept below 1 millisecond (τ < 1 ms) because above 5 millisecond (τ > 5 ms) the achievable attenuation is almost zero (see Elliot, "Signal Processing", Academic Press, London, 2001, figure 6.18 in paragraph 6.5.2). At τ ≈ 1.5 ms feedback and feedforward systems exhibit similar performances.
- (c) The plant delay τ is composed of the delay times of the ANC filter, analog-to-digital converter, digital-to-analog converter, digital signal processor, loudspeaker, microphone and secondary path; the (acoustic) secondary path has a length d (distance between loudspeaker and microphone) provides as acoustic plant delay τa the relevant contribution to the plant delay τ in which τa /d ≈ 3 [ms/m] with a speed of sound 343 m/s at a temperature of 20°C.
- (d) Thus, plant delays τ < 1 ms can only be achieved in case of distances d < 0.33 m, which is the distance between loudspeaker and microphone. According to Elliot's findings feedback ANC systems cannot be used in vehicle cabins if the distance between loudspeaker and microphone is more than 0.4 m. Most common vehicle cabins require, however, a distance of more than 0.4 m.
- (e) A further finding by Stephen Elliott in "A Review of Active Noise and Vibration Control in Road Vehicles", 2008, is, that even if meeting all the requirements outlined above, the maximum critical frequency fUL of the frequency range under noise control is approximately 1/10 of the acoustic aliasing frequency fAcAl = c/2d, in which c is the speed of sound (343 m/s at a temperature of 20° C) and d is the distance between loudspeaker and microphone. The so-called "zone of silence", which is an area around the microphone with a noise attenuation of more than 6 dB, has, according to Elliott, a radius r, in which
-
FIG. 2 shows avehicle cabin 10 in which the active noise reduction system ofFIG. 1 may be applied. In thevehicle cabin 10, e.g., the interior of a Mercedes W211, themicrophone 1 is mounted in the left front portion 11 of thecabin 10, close to a driver's head. Theloudspeaker 2, e.g., a subwoofer, is mounted on therear shelf 12 of thecabin 10. The distance d between themicrophone 1 and theloudspeaker 2 is approximately 3 m. - Simulations have been conducted on the basis of the arrangement of
FIG. 2 , the results of which are shown inFIG. 3. FIG. 3 depicts (a) the magnitude frequency response, (b) the phase frequency response, (c) the sensitivity function and (d) the complementary sensitivity function. The magnitude frequency response is the magnitude in dB over frequency in Hz. The phase frequency response is the phase in degree over frequency in Hz. The sensitivity function N(z), which is the disturbance signal to error signal ratio, can be described as: - in which HOL(z) = W(z)▪S(z) is the transfer function of the open loop of the feedback ANC system.
-
- Both the sensitivity and the complementary functions are depicted in
FIG. 3 c and d as magnitude in dB over frequency in Hz. - From the Bode diagram (magnitude and phase over frequency) 13 of the secondary path in an open loop HOL(z) as shown in FIGS. 3a and b it can be seen that there is an at least theoretical possibility of extending the range of sufficient attenuation up to frequencies of about 100 Hz. Due to the shape of the secondary path, however, it turned out that a sufficient attenuation can only be reached in a range up to 50 Hz which is, nevertheless, about 10 times higher than expected according to Elliott's observations. In the arrangement described above with reference to
FIGS. 1 and 2 , an analog, non-adaptive ANC filter may be used that comprises one boost and one cut equalizing filter with the following dimensioning: - fcEQ1 = 44 Hz, GEQ1 = 21.4 dB, QEQ1 = 4.04,
- fcEQ2 = 82 Hz, GEQ2 = -3.6 dB, QEQ2 = 6.05,
- LG = 1.9 dB,
- in which fcEQ1, fcEQ2 are the corner frequencies, GEQ1, GEQ2 are the maximum/ minimum gain, QEQ1, QEQ2 are the quality factors, and LG is the loop gain. FIGS 3c and 3d illustrate the
corresponding sensitivity function 17 and thecomplementary sensitivity function 19, each in connection with the error margin18. - Referring now to
FIG. 4 ,graphs FIGS. 1 and 2 when the ANC system is not active (20) and when it is active (21). It can readily be seen fromgraph 25 that a maximum attenuation of approximately 8 dB is reached in exact the spectral range identified in the simulations and that the ANC filter used exhibits the so-called "Waterbed Effect" which describes an increase in attenuation in a certain spectral range typical for ANC systems but which may be considered too large in the present case and, thus, may render the system instable under certain conditions. - For an increase in stability, in particular in view of a possible maximum change in the secondary path behavior, e.g., by opening all doors, the loop gain LP may be decreased by, e.g., up to 3 dB. This particular situation is depicted in
FIG. 4 bygraph 22 which represents a system with low-pass filtering and inactive ANC and bygraph 23 which represents a system with low-pass filtering and active ANC; the difference ofgraphs graph 24. Furthermore,graphs - As can be seen and in contrast to the prevailing opinion, the system disclosed herein allows for distances between the microphone and the loudspeaker larger than a value that is determined by the speed of sound divided by 20 times an upper critical frequency. A satisfactory performance may be even achieved, e.g., for distances between the microphone and the loudspeaker that are smaller than or equal to a value that is determined by the speed of sound divided by 2 times an upper critical frequency.
and, for instance, -
FIG. 5 shows a multi-zone ANC system with four zones of silent FL, FR, RL and RR that correspond to driver/passenger positions front left, front right, rear left and rear right. At each position one ofmicrophones loudspeakers microphones loudspeakers - Further investigations have proven that, by applying dedicated circuit structures, the feedback ANC systems described herein are capable of distinguishing between wanted signals, i.e., useful signals such as acoustic warning signals, music and speech, and unwanted signals such as noise. Exemplary circuit structures with specific input paths for the useful signals are described below with reference to
FIGS. 6 ,7 and 8 . -
FIG. 6 is a block diagram illustrating a general feedback type active noise reduction system in which the useful signal is supplied to both the loudspeaker path and the microphone path. For the sake of simplicity, theprimary path 9 is omitted below, notwithstanding that noise (disturbing signal d[n]) is still present. In particular, the system ofFIG. 6 is based on the system ofFIG. 1 , however with anadditional subtractor 26 that subtracts the useful signal x[n] from the microphone output signal y[n] to form the ANC filter input signal, i.e., error signal e[n] and with asubtractor 27 that subtracts the useful signal x[n] from the output signal u[n] ofANC filter 6. -
-
- It can be seen from the above equations that the useful signal transfer characteristic M(z) approaches S(z) when the open loop transfer characteristic (W(z)▪S(z)) approaches 0. Like the system of
FIG. 1 , the system ofFIG. 6 depends on the transfer characteristic S(z) of thesecondary path 3 and its fluctuations due to aging, temperature, change of listener etc. - In
FIG. 7 , a system is shown that is based on the system ofFIG. 6 and that additionally includes an equalizingfilter 28 connected upstream of thesubtractor 27 in order to filter the useful signal x[n] with the inverse secondarypath transfer function 1/S(z). The differential equations describing the system illustrated inFIG. 7 are as follows: -
- As can be seen from the above equations, the microphone output signal y[n] is identical to the useful signal x[n], which means that signal x[n] is not altered by the system if the characteristic of the equalizing filter is exactly the inverse of the secondary path transfer characteristic S(z). Since the secondary path transfer function S(z) in a car is generally not minimum-phase, as can be seen, e.g., from the phase frequency response shown FIGS. 3a and 3b, only approximations of its inverse exist. The probably simplest way is to take the minimum-phase version of S(z), since this can be inverted. Other, more sophisticated but more complex solutions exist as well, that are able to, at least partly, invert the complex transfer function S(z), thus also taking into account, at least partly, its phase characteristic during the inversion process.
- This configuration acts as an ideal linearizer, i.e. it compensates for any deteriorations of the useful signal resulting from its transfer from the
loudspeaker 2 to the microphone, representing ideally the listener's ear. It therefore compensates for, or linearizes, the disturbing influence of the secondary path S(z) to the useful signal x[n], such that the useful signal arrives at the microphone (listener) as provided by the source, without any negative effect caused by the acoustical properties of the vehicle cabin, i.e., y[z] = x[z]. As such, with the help of such a linearizing filter, it is possible to make a poorly designed sound resemble like an acoustically perfectly adjusted, i.e. linear one. - In
FIG. 8 , a system is shown that is based on the system ofFIG. 3 and that additionally includes an equalizingfilter 28 connected upstream of thesubtractor 26 in order to filter the useful signal x[n] with the secondary path transfer function S(z). -
-
- As can be seen, the useful signal transfer characteristic M(z) is identical with the secondary path transfer characteristic S(Z) when the ANC system is active. When the ANC system is inactive, the useful signal transfer characteristic M(z) is also identical with the secondary path transfer characteristic S(Z). Thus, the aural impression of the useful signal for a listener at a location close to the
microphone 1 is the same regardless of whether noise reduction is active or not. This is the most likely way of considering a useful-signal in terms of an automobile environment, since there the useful-signal is mostly music, which should not be disturbed by an algorithm like the feedback ANC system specified here. Furthermore, the thereby needed replica of the secondary path S(z), can, without any problems, be realized in a complex form e.g. as a FIR filter, which, on the other hand, can be made adaptive very easily, e.g. by utilizing one of the multiple forms of the LMS/RLS algorithms. Hence it is shown that, despite the previously mentioned findings of Elliott et al. it is possible to guide a useful signal through a feedback ANC system. - The
ANC filter 6 and the equalizingfilters - Although various examples of realizing the invention have been disclosed, it will be apparent to those skilled in the art that various changes and modifications can be made which will achieve some of the advantages of the invention without departing from the scope of the invention, as defined by the appended claims.
Claims (10)
- A feedback ANC system comprising a microphone (1) and a loudspeaker (2) arranged in a distance of each other; in whichthe microphone (1) is acoustically coupled to the loudspeaker (2) via a secondary path (3); the loudspeaker (2) being electrically coupled to the microphone (1) via an ANC filter (6); andthe distance (d) between the microphone (1) and the loudspeaker (2) is larger than a value that is determined by the speed of sound divided by twenty times an upper critical frequency (fUL) of the ANC system,wherein the distance (d) between the microphone (1) and the loudspeaker (2) is smaller than or equal to a value that is determined by the speed of sound divided by two times an upper critical frequency (fUL),wherein the system further comprises:a first subtractor (26) that is connected downstream of the microphone (1) and a first useful-signal path, wherein the ANC filter (6) is connected downstream of the first subtractor (26); anda second subtractor (27) that is connected upstream of the loudspeaker (2) and connected downstream of the ANC filter (6) and a second useful-signal path; wherein both useful-signal paths are supplied with a useful signal (x[n]) to be reproduced,characterized in thatthe second useful-signal path comprises a second spectrum shaping filter (28) that has a transfer characteristic (1/S(z)) that is equal to the inverse secondary path transfer characteristic.
- The system of claim 1, in which the distance (d) between loudspeaker (2) and microphone (1) is more than 0.34 meter.
- The system of one of claims 1-2, in which the ANC filter (6) is an analog filter.
- The system of one of claims 1-3, in which the ANC filter (6) is a non-adaptive filter.
- The system of one of claims 1-4, further comprising n ≥ 1 additional microphones (1fl1fr, 1rl, 1rr) and n loudspeakers (2fl, 2fr, 2rl, 2rr), each of the loudspeakers (2fl, 2fr, 2rl, 2rr) being arranged in a distance (dfl, dfr, drl, drr) larger than a value that is determined by the speed of sound divided by twenty times an upper critical frequency (fUL).
- The system of claim 5, in which the distance (dfl, dfr, drl, drr) between each microphone (1fl, 1fr, 1rl, 1rr) and each loudspeaker (2fl, 2fr, 2rl, 2rr) is smaller than or equal to a value that is determined by the speed of sound divided by two times an upper critical frequency (fUL).
- The system of claim 4 or 5, further comprising n additional ANC filters (6fl, 6fr, 6rl, 6rr); each additional ANC filter (6fl, 6fr, 6rl, 6rr) being connected between one of the additional microphones(1fl, 1fr, 1rl, 1rr) and one of the additional loudspeakers (2fl, 2fr, 2rl, 2rr).
- The system of one of claims 1-7, in which at least one of the useful-signal paths comprises at least one spectrum shaping filter (28, 29).
- The system of claim 8, in which the secondary path (3) has a secondary path transfer characteristic (S(z)) and at least one of the spectrum shaping filters (28, 29) has a transfer characteristic that models the secondary path transfer characteristic (S(z)) or linearizes a microphone signal output by the microphone (2) with regard to the useful signal (x[n]).
- The system of one of claims 1-9, in which the first useful-signal path comprises a first spectrum (29) shaping filter that has a transfer characteristic (S(z)) that is equal to the secondary path transfer characteristic.
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CN104616667B (en) * | 2014-12-02 | 2017-10-03 | 清华大学 | A kind of active denoising method in automobile |
EP3338279A1 (en) * | 2015-08-20 | 2018-06-27 | Cirrus Logic International Semiconductor Ltd. | Feedback adaptive noise cancellation (anc) controller and method having a feedback response partially provided by a fixed-response filter |
EP3185241B1 (en) * | 2015-12-23 | 2020-02-05 | Harman Becker Automotive Systems GmbH | Externally coupled loudspeaker system |
CN106143369B (en) * | 2016-07-05 | 2018-07-03 | 同济大学 | A kind of stroke-increasing electric automobile noise impedance device |
TWI609363B (en) * | 2016-11-23 | 2017-12-21 | 驊訊電子企業股份有限公司 | Calibration system for active noise cancellation and speaker apparatus |
DE102017126883B4 (en) * | 2017-11-15 | 2022-07-28 | Linde Material Handling Gmbh | Work vehicle with noise reduction in a driver's cab |
US10339912B1 (en) * | 2018-03-08 | 2019-07-02 | Harman International Industries, Incorporated | Active noise cancellation system utilizing a diagonalization filter matrix |
CN108538304B (en) * | 2018-03-09 | 2021-10-01 | 华侨大学 | Active control system for noise in vehicle |
CN108615523B (en) * | 2018-05-08 | 2022-10-04 | 南京信息工程大学 | Frequency domain self-adaption method for adjusting water bed effect of feedback active control system |
CN114582312B (en) * | 2022-02-14 | 2022-11-22 | 中国科学院声学研究所 | Active control method and system for anti-interference adaptive road noise in vehicle |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0632532B2 (en) * | 1984-11-07 | 1994-04-27 | 日産自動車株式会社 | Vehicle interior noise reduction device |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS60183900A (en) * | 1984-03-02 | 1985-09-19 | Mazda Motor Corp | Device for improving sound in automobile |
US5953428A (en) * | 1996-04-30 | 1999-09-14 | Lucent Technologies Inc. | Feedback method of noise control having multiple inputs and outputs |
JPH11305784A (en) * | 1998-04-24 | 1999-11-05 | Matsushita Electric Ind Co Ltd | Noise controller |
DE602004015242D1 (en) * | 2004-03-17 | 2008-09-04 | Harman Becker Automotive Sys | Noise-matching device, use of same and noise matching method |
JP2008247221A (en) * | 2007-03-30 | 2008-10-16 | Honda Motor Co Ltd | Active noise control device |
ATE518381T1 (en) * | 2007-09-27 | 2011-08-15 | Harman Becker Automotive Sys | AUTOMATIC BASS CONTROL |
US9020158B2 (en) * | 2008-11-20 | 2015-04-28 | Harman International Industries, Incorporated | Quiet zone control system |
-
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---|---|---|---|---|
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