Acoustic system and signal processing method

Abstract

An embodiment of the present specification provides an acoustic system and a signal processing method, a pickup assembly in the acoustic system converts an ambient sound into a first audio signal, the ambient sound including a first sound from a speaker and a second sound from a target sound source, a first peripheral circuit connecting a signal processing circuit and the speaker, and a second peripheral circuit connecting the signal processing circuit and the speaker. A reference signal pickup point exists in the first peripheral circuit, and the second peripheral circuit is connected with the reference signal pickup point and the signal processing circuit, obtains a first reference signal from the reference signal pickup point during working, and outputs a second reference signal to the signal processing circuit. Therefore, the signal processing circuit reduces components corresponding to the first sound in the first audio signal based on the second reference signal to obtain a target signal. As the feedback component in the target signal is reduced or eliminated, howling generated by the acoustic system can be avoided or inhibited, and the maximum forward gain which can be obtained by the acoustic system can be improved.

Description

Acoustic system and signal processing method Technical Field

[0001] This specification relates to the field of acoustic technology, and in particular to an acoustic system and a signal processing method. Background Art

[0002] Some acoustic systems include both speakers and sound sensors. These acoustic systems often suffer from the problem of acoustic feedback. Acoustic feedback refers to the process in which a sound sensor collects sound from the environment and obtains a sound signal. This signal is then processed and played back through a speaker, and the sound emitted by the speaker is then re-collected by the sound sensor, forming a closed loop of "speaker->sound sensor->speaker" in the acoustic system. In the above-mentioned acoustic system, the sound from the speaker picked up by the sound sensor can be called feedback sound. The presence of feedback sound causes some problems in the acoustic system. For example, it can cause problems such as howling in the acoustic system and may also limit the maximum forward gain that the acoustic system can achieve. Therefore, there is a need to provide an acoustic solution that can reduce or eliminate feedback components.

[0003] Summary of the Invention

[0004] This specification provides an acoustic system and a signal processing method that can reduce or eliminate feedback sound, thereby avoiding problems such as howling in the acoustic system and further improving the maximum forward gain that can be achieved by the acoustic system.

[0005] In a first aspect, the present specification provides an acoustic system, comprising: a loudspeaker, a sound pickup assembly, a signal processing circuit, a first peripheral circuit, and a second peripheral circuit. The loudspeaker, when in operation, converts a driving signal into a first sound; the sound pickup assembly, when in operation, converts ambient sound into a first audio signal, the ambient sound comprising the first sound and a second sound from a target sound source; the signal processing circuit is connected to the sound pickup assembly; the first peripheral circuit comprises an input port and an output port, the output port being connected to the loudspeaker; a reference signal pickup point is present in the first peripheral circuit; and the second peripheral circuit connects the reference signal pickup point to the signal processing circuit. When in operation, the first peripheral circuit obtains a second audio signal through the input port, converts the second audio signal into the driving signal, and transmits the driving signal to the loudspeaker through the output port; when in operation, the second peripheral circuit obtains a first reference signal from the reference signal pickup point and outputs a second reference signal to the signal processing circuit; and when in operation, the signal processing circuit, based on the second reference signal, reduces a signal component corresponding to the first sound in the first audio signal to obtain a target signal, and performs a target operation on the target signal.

[0006] In some embodiments, the type of the first reference signal includes at least one of an analog signal, a pulse width modulation PWM signal, a pulse density modulation PDM signal, a pulse code modulation PCM signal, an integrated circuit built-in audio I2S signal, or a time division multiplexing TDM signal.

[0007] In some embodiments, the reference signal pickup point is located at the input port; or, the reference signal pickup point is located at the output port.

[0008] In some embodiments, the first peripheral circuit further includes a first processing component, which is connected to the signal processing circuit via the input port, obtains the second audio signal from the signal processing circuit during operation, and performs at least one of a digital-to-analog conversion operation, a modulation operation, and a filtering operation on the second audio signal; and the reference signal pickup point is located between the first processing component and the output port.

[0009] In some embodiments, the first peripheral circuit further includes a second processing component connecting the first processing component and the output port, wherein the reference signal pickup point is located between the first processing component and the second processing component, or the reference signal pickup point is located between the second processing component and the output port, or the second processing component includes multiple circuit elements, and the reference signal pickup point is located between any two circuit elements among the multiple circuit elements.

[0010] In some embodiments, the second audio signal is derived from the target signal.

[0011] In some embodiments, the second audio signal includes a first signal component and a second signal component, wherein the first signal component comes from the target signal and the second signal component comes from a target audio component that is different from the pickup component.

[0012] In some embodiments, the input port includes K branch ports, where K is an integer greater than 1; the second audio signal includes K branch audio signals; and the first peripheral circuit obtains the K branch audio signals through the K input ports and converts the K branch audio signals into the driving signal.

[0013] In some embodiments, the first peripheral circuit further includes a third processing component that performs at least one of a digital-to-analog conversion operation, a modulation operation, a filtering operation, and a stream mixing operation on the K branch audio signals during operation; and the reference signal pickup point is located between the third processing component and the output port.

[0014] In some embodiments, the first peripheral circuit further includes: K branch processing components, respectively connected to the K branch ports, wherein the i-th branch processing component performs at least one of a digital-to-analog conversion operation, a modulation operation, and a filtering operation on the i-th branch audio signal during operation to obtain the i-th intermediate audio signal; and a first mixing component, respectively connected to the K third processing components, performing a mixing operation on the K intermediate audio signals during operation; and the reference signal pickup point is located between the first mixing component and the output port.

[0015] In some embodiments, the first peripheral circuit further includes: a second mixing component, which is respectively connected to the K branch ports, and performs a mixing operation on the K branch audio signals during operation to obtain a mixed audio signal; and a fourth processing component, which is connected to the second mixing component, and performs at least one of a digital-to-analog conversion operation, a modulation operation, and a filtering operation on the mixed audio signal during operation; and the reference signal pickup point is located between the second mixing component and the fourth processing component, or the reference signal pickup point is located between the fourth processing component and the output port.

[0016] In some embodiments, the branch audio signals obtained by the first peripheral circuit through the K branch ports all come from the target signal.

[0017] In some embodiments, the K branch ports include a first portion of branch ports and a second portion of branch ports, wherein the branch audio signal obtained by the first peripheral circuit through the first portion of branch ports comes from the target signal, and the branch audio signal obtained by the first peripheral circuit through the second portion of branch ports comes from a target audio component, and the target audio component is different from the pickup component.

[0018] In some embodiments, when the second peripheral circuit is running, it performs at least one of analog-to-digital conversion, demodulation, filtering, and gain operation on the first reference signal to obtain the second reference signal.

[0019] In some embodiments, to obtain the target signal, the signal processing circuit: performs an adaptive filtering operation on the second reference signal to obtain a filtered signal; and subtracts the filtered signal from the first audio signal to obtain the target signal.

[0020] In some embodiments, the signal processing circuit further updates filtering parameters corresponding to the adaptive filtering operation based on at least one of the target signal and the second reference signal.

[0021] In some embodiments, when executing the target operation, the signal processing circuit: performs a gain amplification operation on the target signal to obtain an amplified signal; and sends the amplified signal to the first peripheral circuit.

[0022] In some embodiments, the sound pickup component includes a sound sensor and a third peripheral circuit, wherein the sound sensor converts the ambient sound into a sound pickup signal when in operation, and the third peripheral circuit converts the sound pickup signal into the first audio signal when in operation.

[0023] In some embodiments, the signal processing circuit includes: at least one storage medium and at least one processor, wherein the at least one storage medium stores at least one instruction set for performing signal processing; the at least one processor is communicatively connected to the first peripheral circuit, the second peripheral circuit, the pickup assembly and the at least one storage medium, wherein, when the acoustic system is operating, the at least one processor reads the at least one instruction set and executes according to the instructions of the at least one instruction set: based on the second reference signal, reducing the signal component corresponding to the first sound in the first audio signal to obtain a target signal, and performing the target operation on the target signal.

[0024] In a second aspect, the present specification also provides a signal processing method, comprising: obtaining, through a signal processing circuit in an acoustic system: a first audio signal, wherein the first audio signal is obtained by converting ambient sound by a sound pickup component in the acoustic system, and the ambient sound includes a first sound and a second sound, the first sound is a sound from a loudspeaker in the acoustic system, and the second sound is a sound from a target sound source; obtaining a second reference signal, wherein the second reference signal is obtained by a second peripheral circuit in the acoustic system based on the first reference signal, wherein the first reference signal is obtained by the second peripheral circuit from a reference signal pickup point of a first peripheral circuit in the acoustic system, and the first peripheral circuit is connected to the signal processor and the loudspeaker; based on the second reference signal, reducing the signal component corresponding to the first sound in the first audio signal to obtain a target signal; and performing a target operation on the target signal.

[0025] In some embodiments, the type of the first reference signal includes at least one of an analog signal, a pulse width modulation PWM signal, a pulse density modulation PDM signal, a pulse code modulation PCM signal, an integrated circuit built-in audio I2S signal, or a time division multiplexing TDM signal.

[0026] In some embodiments, based on the second reference signal, reducing the signal component corresponding to the first sound in the first audio signal to obtain a target signal includes: performing an adaptive filtering operation on the second reference signal to obtain a filtered signal; and subtracting the filtered signal from the first audio signal to obtain the target signal.

[0027] In some embodiments, the method further includes: updating filtering parameters corresponding to the adaptive filtering operation based on at least one of the target signal and the second reference signal.

[0028] As can be seen from the above technical solution, in the acoustic system and signal processing method provided in this specification, the pickup component in the acoustic system converts ambient sound into a first audio signal, wherein the ambient sound includes a first sound from a speaker and a second sound from a target sound source. The first peripheral circuit connects the signal processing circuit and the speaker, and there is a reference signal pickup point in the first peripheral circuit. The second peripheral circuit connects the reference signal pickup point and the signal processing circuit. During operation, a first reference signal is obtained from the reference signal pickup point, and a second reference signal is output to the signal processing circuit. Therefore, the signal processing circuit reduces the component corresponding to the first sound in the first audio signal based on the second reference signal to obtain a target signal. Since the feedback component in the target signal is reduced or eliminated, it is possible to avoid or suppress howling in the acoustic system, and also helps to improve the maximum forward gain that can be achieved by the acoustic system.

[0029] Other functions of the acoustic system and signal processing method provided in this specification will be partially listed in the following description. The creative aspects of the acoustic system and signal processing method provided in this specification can be fully explained by practicing or using the methods, devices and combinations described in the following detailed examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of this specification, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0031] FIG1 shows a schematic diagram of an application scenario provided according to an embodiment of this specification;

[0032] FIG2 is a schematic diagram showing the principle of feedback sound elimination based on AFC technology;

[0033] 3A to 3C show several schematic diagrams of an acoustic system according to an embodiment of this specification;

[0034] 4A to 4C are schematic diagrams showing several locations of reference signal pickup points in an acoustic system;

[0035] 5A to 5C are schematic diagrams showing the connection of K branch ports of a first peripheral circuit in an acoustic system;

[0036] 6A to 6D are schematic diagrams showing several other positions of reference signal pickup points in an acoustic system;

[0037] FIG7 shows a test result of filtering performance of an acoustic system provided according to an embodiment of this specification;

[0038] FIG8 shows a schematic diagram of a hardware structure of an acoustic system provided according to an embodiment of this specification; and

[0039] FIG9 is a schematic flow chart showing a signal processing method according to an embodiment of this specification. DETAILED DESCRIPTION

[0040] The following description provides specific application scenarios and requirements for this specification, with the goal of enabling those skilled in the art to make and use the contents of this specification. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of this specification. Therefore, this specification is not limited to the embodiments shown, but is intended to be accorded the broadest scope consistent with the claims.

[0041] The terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. For example, as used herein, the singular forms "a," "an," and "the" may also include the plural forms unless the context clearly indicates otherwise. When used in this specification, the terms "comprise," "include," and / or "contain" are intended to refer to the presence of the associated integers, steps, operations, elements, and / or components, but do not preclude the presence of one or more other features, integers, steps, operations, elements, components, and / or groups or the addition of other features, integers, steps, operations, elements, components, and / or groups in the system / method.

[0042] These and other features of this specification, as well as the operation and function of the associated elements of the structure, and the economical assembly and manufacture of the components, can be significantly improved with consideration of the following description. Reference is made to the accompanying drawings, all of which form a part of this specification. However, it should be expressly understood that the drawings are for illustration and description purposes only and are not intended to limit the scope of this specification. It should also be understood that the drawings are not drawn to scale.

[0043] The flowcharts used in this specification illustrate operations implemented by systems according to some embodiments of the present specification. It should be clearly understood that the operations of the flowcharts may not be implemented in sequence. Rather, the operations may be implemented in reverse order or simultaneously. Furthermore, one or more additional operations may be added to the flowcharts. One or more operations may be removed from the flowcharts.

[0044] Before describing the specific embodiments of this specification, the following describes the application scenarios of this specification. The solution provided in this specification can be applied to scenarios where feedback sound needs to be reduced or eliminated. An example is provided below with reference to FIG1.

[0045] FIG1 shows a schematic diagram of an application scenario provided according to an embodiment of this specification. As shown in FIG1 , application scenario 001 can be a sound amplification scenario, a hearing aid scenario, an assisted listening scenario, etc. In this scenario, the acoustic system can include a speaker 110 and a sound sensor 120. When the sound sensor 120 is in operation, it collects ambient sound. In this specification, ambient sound refers to the sound in the environment, that is, the ambient sound can include the sound emitted by all sound sources in the environment. During the sound pickup process of the sound sensor 120, if the speaker 110 and the target sound source 160 are both emitting sound, the ambient sound collected by the sound sensor 120 includes both the sound from the target sound source 160 and the sound from the speaker 110. Furthermore, the signal collected by the sound sensor 120 is amplified by the forward gain (G) and then sent to the speaker 110 to drive the speaker 110 to emit sound. In this way, a closed loop of "speaker->sound sensor->speaker" is formed in the acoustic system. In this case, when the sound signal of a certain frequency undergoes self-excited oscillation, a howling phenomenon will occur. Such howling can make users feel uncomfortable and, when severe, can damage components in the acoustic system. Furthermore, the presence of the howling also limits the forward gain amplification of the acoustic system, thereby restricting the maximum forward gain that the acoustic system can achieve.

[0046] It should be noted that the application scenarios shown in FIG1 above are only some of the multiple application scenarios applicable to this application. The acoustic system provided in this application can also be applied to other similar scenarios, which are not listed one by one in this specification. Those skilled in the art should understand that the application of the solution provided in this application to other usage scenarios is also within the scope of protection of this application.

[0047] In summary, the presence of feedback sound can cause a series of problems in the acoustic system, including but not limited to: generating howling and limiting the maximum forward gain that the acoustic system can achieve.

[0048] In some embodiments, the acoustic system may use acoustic feedback cancellation (AFC) technology to reduce or eliminate feedback sound. To facilitate subsequent description, the principle of AFC technology is first introduced below with reference to FIG2 .

[0049] FIG2 is a schematic diagram showing the principle of feedback sound elimination based on AFC technology. As shown in FIG2 , the acoustic system may include a sound generating component 10 , a sound pickup component 20 and a signal processing circuit 150 .

[0050] Among them, the pronunciation component 10 is a component with a pronunciation function. The pronunciation component 10 can be connected to the output end of the signal processing circuit 150, and when working, receives the second audio signal u from the signal processing circuit 150 and converts it into sound and plays it out. Continuing to refer to Figure 2, the pronunciation component 10 may include a loudspeaker 110 and a first peripheral circuit 130 (C1 is used in the accompanying drawings to represent the first peripheral circuit). Among them, the loudspeaker 110 is a device for converting an electrical signal into sound, and can also be called an electroacoustic converter. For example, the loudspeaker 110 can be a speaker. The first peripheral circuit 130 is connected between the output end of the signal processing circuit 150 and the loudspeaker 110. The first peripheral circuit 130 can refer to all circuits or part of the circuits between the output end of the signal processing circuit 150 and the loudspeaker 110. The first peripheral circuit 130 can perform some processing on the electrical signal (i.e., the second audio signal u) output by the signal processing circuit 150, so that the processed electrical signal is suitable for playback by the loudspeaker 110. For ease of description, the electrical signal processed by the first peripheral circuit 130 will be referred to as a driving signal u″′ hereinafter. The first peripheral circuit 130 may include at least one circuit element, and the at least one circuit element includes but is not limited to an operational amplifier device, a power amplifier device, a digital-to-analog converter device, a filter device, a modulation device, a demodulation device, a capacitor, a resistor, an inductor, a chip, and other devices.

[0051] It should be noted that the speaker 110 can be a device that produces sound based on at least one conduction method among gas, liquid, and solid, and the embodiments of this specification do not limit this. The speaker 110 can be the speaker itself, or it can include the speaker and its accompanying simple circuit elements. The number of speakers 110 can be one or more. When the number of speakers 110 is multiple, the multiple speakers 110 can be arranged in an array. In addition, when the number of speakers 110 is multiple, the multiple speakers 110 can be connected to the signal processing circuit 150 through the same first peripheral circuit 130, or the multiple speakers 110 can be connected to the signal processing circuit 150 through different first peripheral circuits 130.

[0052] The sound pickup component 20 is a component with a sound pickup function. The sound pickup component 20 can be connected to the input end of the signal processing circuit 150. When in operation, it picks up ambient sound to generate a first audio signal y and sends the first audio signal y to the signal processing circuit 150. Continuing to refer to Figure 2, the sound pickup component 20 may include a sound sensor 120 and a third peripheral circuit 140 (C3 is used in the figure to represent the third peripheral circuit). Among them, the sound sensor 120 is a device for picking up ambient sound and converting the ambient sound into an electrical signal, and may also be called an acoustic-to-electrical converter. For example, the sound sensor 120 may be a microphone (MIC). For ease of description, the electrical signal obtained by the sound sensor 120 collecting ambient sound and converting it is called the sound pickup signal y′. The third peripheral circuit 140 is connected between the sound sensor 120 and the input end of the signal processing circuit 150. The third peripheral circuit 140 may refer to all circuits or part of the circuits between the sound sensor 120 and the input end of the signal processing circuit 150. The third peripheral circuit 140 can process the electrical signal picked up by the sound sensor 120 (i.e., the sound pickup signal y′), convert it into a first audio signal y, and send the first audio signal y to the signal processing circuit 150. The third peripheral circuit 140 can include at least one circuit element, which can include but is not limited to a power amplifier, an operational amplifier, an analog-to-digital converter, a filter, a modulation device, a demodulation device, a capacitor, a resistor, an inductor, a chip, and other devices.

[0053] It should be noted that the sound sensor 120 can be a device that picks up sound based on at least one conductive method among gas, liquid, and solid, and this specification does not limit this. The sound sensor 120 can be the MIC itself, or it can include the MIC and its accompanying simple circuit elements. The number of sound sensors 120 can be one or more. When the number of sound sensors 120 is multiple, the multiple sound sensors 120 can be arranged in an array. In addition, when the number of sound sensors 120 is multiple, the multiple sound sensors 120 can be connected to the signal processing circuit 150 through the same third peripheral circuit 140, or the multiple sound sensors 120 can also be connected to the signal processing circuit 150 through different third peripheral circuits 140.

[0054] Continuing to refer to Figure 2, the working process of the acoustic system is as follows: the sound component 10 receives the second audio signal u from the signal processing circuit 150 and converts it into a first sound. The target sound source 160 emits a second sound. The target sound source 160 may refer to other sound sources in the environment other than the sound component 10. For example, the target sound source 160 may include an electronic device with a sound playback function (such as a TV, a speaker, a mobile phone, etc.); for another example, the target sound source 160 may also include a human throat. The sound pickup component 20 collects the ambient sound and converts the ambient sound into a first audio signal y. The ambient sound includes a first sound from the sound component 10 and a second sound from the target sound source 160. Therefore, the first audio signal y includes both a signal component x corresponding to the first sound and a signal component v corresponding to the second sound. The sound pickup component 20 sends the first audio signal y to the signal processing circuit 150.

[0055] The signal processing circuit 150 can be a circuit with certain signal processing capabilities. The input of the signal processing circuit 150 is connected to the sound pickup component 20, and the output is connected to the sound production component 10. The signal processing circuit 150 can obtain a first audio signal y from the sound pickup component 20 and perform a preset signal processing process on the first audio signal y using AFC technology to obtain a second audio signal u (i.e., a new second audio signal u, or a second audio signal u at the next moment). Furthermore, the signal processing circuit 150 transmits the second audio signal u to the sound production component 10 to drive the sound production component 10 to produce sound. The signal processing process involved in AFC technology is described in detail below with reference to FIG2.

[0056] Continuing with FIG. 2 , to reduce or eliminate feedback components in an acoustic system, the signal processing circuit 150 may include an acoustic feedback cancellation unit 151. The inputs to the acoustic feedback cancellation unit 151 include a first audio signal y and a second audio signal u. For example, the acoustic feedback cancellation unit 151 may obtain the second audio signal u from other processing units within the signal processing circuit 150 and the first audio signal y from the pickup assembly 20. Based on the second audio signal u, the acoustic feedback cancellation unit 151 may reduce the signal component (i.e., the feedback component) in the first audio signal y corresponding to the first sound, thereby obtaining a signal e.

[0057] Specifically, the principle of the above reduction is as follows: the acoustic feedback cancellation unit 151 can solve and adaptively update a time-varying transfer function F' to fit the transfer function F corresponding to the feedback path (i.e., the transmission path of the feedback sound). For the sake of distinction, the transfer function F' obtained by solution will be referred to as the predicted transfer function F', and the transfer function F corresponding to the feedback path will be referred to as the true transfer function F. Continuing to refer to Figure 2, the acoustic feedback cancellation unit 151 uses the predicted transfer function F' to perform an adaptive filtering operation on the second audio signal u to obtain a signal x', i.e., x'=u*F'. The signal x' can be regarded as a predicted value of the feedback component in the first audio signal y (i.e., the signal component in the first audio signal y corresponding to the first sound). Furthermore, the acoustic feedback cancellation unit 151 can subtract the signal x' from the first audio signal y to obtain a signal e, i.e., e=y-x'. The signal e obtained in this way does not contain or contains less feedback components.

[0058] It should be noted that the acoustic feedback cancellation unit 151 can use a variety of adaptive filtering algorithms to solve the predicted transfer function F', such as least mean square (LMS), normalized least mean square (NLMS), recursive least squares (RLS), other adaptive filtering algorithms, and any derivative algorithms of the above-mentioned algorithms, etc., and this specification does not limit this. In addition, the adaptive filtering algorithm can be adaptive filtering in the time domain, frequency domain, or other transform domains.

[0059] Continuing with FIG2 , the signal processing circuit 150 may further include a gain amplification unit 152. The gain amplification unit 152 may perform a gain amplification operation on the signal e to generate an amplified signal. The signal processing circuit 150 then transmits the amplified signal as the second audio signal u (i.e., a new second audio signal u, or the second audio signal u at the next moment) to the sound generating component 10 to drive the sound generating component 10 to generate sound.

[0060] According to the theory of adaptive filtering algorithm, the update method of the predicted transfer function F' can be achieved by minimizing the expectation of the mean square function of the signal e, that is: min F′ E[e 2 ]=min F′ E[(yu*F′) 2 ] Formula (1-1)

[0061] For example, taking the acoustic feedback cancellation unit 151 using the LMS algorithm as an example, the above formula (1-1) is derived based on the gradient descent optimization method, and the update formula of the predicted transfer function F' can be obtained as follows: F'←F'+μ*e*u Formula (2-1)

[0062] Where μ is the iteration step size.

[0063] It should be understood that when the acoustic feedback cancellation unit 151 adopts algorithms such as NLMS and RLS, the update formula of the predicted transfer function F' can be derived in a similar manner, and this specification does not provide examples one by one for this purpose.

[0064] In summary, the acoustic system shown in FIG2 performs an AFC algorithm based on the first audio signal y and the second audio signal u, which can reduce or eliminate the feedback component in the first audio signal y, thereby avoiding problems such as howling caused by the feedback component, and helps to improve the maximum forward gain that the acoustic system can achieve.

[0065] According to signal processing theory, the closed-loop gain A of the acoustic system shown in Figure 2 can be expressed as follows:

[0066] According to the Nyquist stability criterion, an acoustic system must be able to cancel feedback components if the predicted transfer function F' is exactly equal to the true transfer function F, that is, F' = F. When this requirement is met, the acoustic system is always stable and does not produce howling. Furthermore, the acoustic system can achieve infinite gain. That is, when the forward gain G → ∞, A = G → ∞.

[0067] However, in actual acoustic systems, since the true transfer function F may be time-varying and the convergence process of the iterative solution may oscillate, it is difficult for the iterative process of F' to achieve the ideal condition F' = F. In other words, there is a certain deviation between the predicted transfer function F' obtained by the actual iteration and the true transfer function F. In this case, in order to keep the acoustic system stable, the forward gain G provided by the gain amplifier unit 152 naturally cannot be infinite. The maximum forward gain that the acoustic system can achieve is:

[0068] As can be seen from formula (4), the deviation between the predicted transfer function F′ and the true transfer function F can be used to measure the convergence performance of the adaptive filtering algorithm, and thus the acoustic system's ability to cancel out feedback components. Specifically, the smaller the deviation between the predicted transfer function F′ and the true transfer function F, the better the convergence performance of the adaptive filtering algorithm, and thus the better the acoustic system's ability to cancel out feedback components. The larger the deviation between the predicted transfer function F′ and the true transfer function F, the worse the convergence performance of the adaptive filtering algorithm, and thus the worse the acoustic system's ability to cancel out feedback components.

[0069] In some embodiments, we can also use misalignment (MIS) to measure the convergence performance of the adaptive filtering algorithm. The misalignment MIS can be expressed as follows:

[0070] The unit of offset MIS is decibel (dB). When the predicted transfer function F' is initialized to zero, the offset MIS is 0dB. As the offset MIS decreases and approaches negative infinity, the deviation between the predicted transfer function F' and the true transfer function F decreases, indicating better convergence of the adaptive filtering algorithm and, consequently, better feedback cancellation by the acoustic system. As the offset MIS increases and approaches positive infinity, the deviation between the predicted transfer function F' and the true transfer function F increases, indicating worse convergence of the adaptive filtering algorithm and, consequently, worse feedback cancellation by the acoustic system.

[0071] It should be noted that the convergence performance of the adaptive filtering algorithm in this application includes, but is not limited to, convergence speed, convergence error, etc. The convergence speed may refer to the speed at which the predicted transfer function F′ fits the true transfer function F, and the convergence error may refer to the deviation between the predicted transfer function F′ and the true transfer function F when the convergence condition is met.

[0072] In practical applications, the design architecture of some acoustic systems limits access rights or communication capabilities between different units. For example, the acoustic feedback cancellation unit 151 cannot obtain the second audio signal u from other units within the signal processing circuit 150. Therefore, such acoustic systems cannot use AFC technology to reduce or eliminate feedback components.

[0073] In addition, in the feedback component elimination scheme shown in Figure 2, the reason why a time-varying predicted transfer function F′ can be solved by an adaptive filtering algorithm to fit the actual transfer function F is based on the following ideal assumption: the feedback paths in the acoustic system are all linear transmissions, or in other words, the responses of the feedback paths are all linear responses. However, actual acoustic systems generally cannot meet this ideal assumption. In actual acoustic systems, nonlinear response components are generally present in the first peripheral circuit 130. For example, the digital-to-analog converter devices, filtering devices, modulation devices, etc. in the first peripheral circuit 130 generally exhibit nonlinear responses.

[0074] Based on the principles of the adaptive filtering algorithm, since the acoustic feedback cancellation unit 151 obtains the second audio signal u from other units within the signal processing circuit 150 (i.e., obtains the second audio signal u at a location before the output of the signal processing circuit 150), the feedback path of the feedback sound actually includes the transmission path from the point where the acoustic feedback cancellation unit 151 extracts the second audio signal u (which can be roughly regarded as the output of the signal processing circuit 150) to the point where the acoustic feedback cancellation unit 151 extracts the first audio signal y (which can be roughly regarded as the input of the signal processing circuit 150). In other words, the transmission effect of the above-mentioned feedback path not only includes the transmission effect of the spatial path between the sound producing component 10 and the sound pickup component 20, but also includes the transmission effect of the sound producing component 10 itself (i.e., the transmission effect of the first peripheral circuit 130 and the speaker 110), and the transmission effect of the sound pickup component 20 itself (i.e., the transmission effect of the sound sensor 120 and the third peripheral circuit 140). Therefore, when the feedback component cancellation scheme shown in Figure 2 is applied to an actual acoustic system, the predicted transfer function F′ actually simulates the overall transfer effect of the feedback path, that is, it simulates the overall transfer effect of the first peripheral circuit 130, the speaker 110, the spatial path between the speaker 110 and the sound sensor 120, the sound sensor 120, and the third peripheral circuit 140.

[0075] Since there are nonlinear response components in the first peripheral circuit 130, the nonlinear response components are inevitably introduced into the iterative solution of the predicted transfer function F′, which will result in low convergence performance of the adaptive filtering algorithm, for example, causing the predicted transfer function F′ to fail to converge, converge slowly, or have a large convergence error. In addition, there may also be cached or delay effects in the first peripheral circuit 130. The above cache or delay effects will cause a certain time offset in the solved predicted transfer function F′. Since the order of the adaptive filtering algorithm is usually limited, especially in acoustic systems with high real-time requirements and insufficient computing resources, the order of the adaptive filtering algorithm is low. Therefore, when the above cache or delay effects are significant, the convergence performance of the adaptive filtering algorithm will also be reduced. Those skilled in the art will understand that when the convergence performance of the adaptive filtering algorithm is low, the offset index MIS of the acoustic system deteriorates and the offset effect of the feedback component deteriorates.

[0076] In order to solve at least one of the above technical problems, the acoustic system provided in this specification can obtain a second reference signal from the electrical space, and eliminate the feedback component in the first audio signal y based on the second reference signal.

[0077] Figure 3A shows a schematic diagram of an acoustic system provided according to an embodiment of the present specification. As shown in Figure 3A, the acoustic system may include a sound-producing component 10, a sound-collecting component 20, and a signal processing circuit 150. The sound-producing component 10 may include a speaker 110 and a first peripheral circuit 130, the sound-collecting component 20 may include a sound sensor 120 and a third peripheral circuit 140, and the signal processing circuit 150 may include an acoustic feedback cancellation unit 151. When the acoustic system is working, the sound-collecting component 20 picks up ambient sound, converts the ambient sound into a first audio signal y, and sends the first audio signal y to the signal processing circuit 150. After receiving the first audio signal y, the signal processing circuit 150 uses the acoustic feedback cancellation unit 151 to process the first audio signal y to reduce the feedback component in the first audio signal y, thereby obtaining a target signal e.

[0078] Continuing to refer to Figure 3A, the speaker 110 and the signal processing circuit 150 are connected through the first peripheral circuit 130. The first peripheral circuit 130 may include an input port 131 and an output port 132. The input port 131 refers to the port where the first peripheral circuit 130 is connected to the signal processing circuit 150, and the output port 132 refers to the port where the first peripheral circuit 130 is connected to the speaker 110. When the first peripheral circuit 130 is running, it obtains the second audio signal u through the input port 131, converts the second audio signal u into a driving signal u″′, and sends the driving signal u″′ to the speaker 110 through the output port 132 to drive the speaker 110 to make a sound.

[0079] In some embodiments, the second audio signal u obtained by the first peripheral circuit 130 through the input port 131 can be derived from the target signal e. Here, "the second audio signal u is derived from the target signal e" can include the following two situations. Situation 1: The second audio signal u and the target signal e are the same signal; Situation 2: The second audio signal u is a signal obtained by performing a preset process on the target signal e. The preset process can include one or more of gain amplification, frequency division, filtering, or other possible processing methods. Figure 3A illustrates the above-mentioned situation 2. For example, referring to Figure 3A, the signal processing circuit 150 can further include a gain amplification unit 152, which can perform a gain amplification operation on the target signal e to obtain the second audio signal u. In this case, the input port 131 of the first peripheral circuit 130 can be connected to the gain amplification unit 152. In this way, the second audio signal u obtained by the first peripheral circuit 130 through the input port 131 is a signal obtained by performing a gain amplification on the target signal e. In other words, the second audio signal u is derived from the target signal e.

[0080] In the acoustic system shown in FIG3A , all signal components in the second audio signal u are derived from the target signal e. Thus, a signal loop is formed between the sound pickup assembly 20, the acoustic feedback cancellation unit 151, the gain amplification unit 152, the first peripheral circuit 130, and the speaker 110. However, in some cases, only a portion of the signal components in the second audio signal u may be derived from the target signal e.

[0081] Specifically, the second audio signal u may include a first signal component and a second signal component, wherein the first signal component is derived from the target signal e, and the second signal component is derived from a target audio component. The target audio component is a component other than the sound pickup component 20 that has an audio output function. The target audio component may be a component integrated into the signal processing circuit 150 or a component external to the signal processing circuit 150 (for example, the target audio component may be integrated into another circuit within the acoustic system other than the signal processing circuit 150, or may be another external acoustic device).

[0082] For example, in some embodiments, the target audio component 200 can be a Bluetooth component, which can be integrated into the signal processing circuit 150 or integrated into other circuit systems. The Bluetooth component can receive Bluetooth audio signals from an external acoustic device. In some embodiments, the target audio component 200 can be a codec component built into the signal processing circuit 150, which can decode the built-in audio to generate a prompt tone. In some embodiments, the target audio component 200 can also be other external components / external devices connected to the acoustic system by wire.

[0083] Figure 3B shows another schematic diagram of an acoustic system provided according to an embodiment of the present specification. As shown in Figure 3B, the signal processing circuit 150 may also include a first audio component 200 (marked as Y1 in the accompanying drawings). The first audio component 200 can be connected to the gain amplification unit 152. The first audio component 200 can provide a signal n1 to the gain amplification unit 152. In this way, the gain amplification unit 152 can obtain the target signal e from the acoustic feedback cancellation unit 151 on the one hand, and obtain the signal n1 from the first audio component 200 on the other hand. The gain amplification unit 152 can obtain the second audio signal u after performing gain amplification processing on the target signal e and the signal n1, as well as appropriate mixing and superposition calculations. It can be seen that in this case, part of the signal components in the second audio signal u come from the target signal e, and the other part of the signal components come from the first audio component 200.

[0084] Figure 3C shows another schematic diagram of an acoustic system provided according to an embodiment of the present specification. As shown in Figure 3C, the acoustic system may further include a second audio component 300 (marked as Y2 in the accompanying drawing), and the second audio component 300 is located outside the signal processing circuit 150. The second audio component 300 can be connected to the gain amplification unit 152. The second audio component 300 can provide a signal n2 to the gain amplification unit 152. In this way, the gain amplification unit 152 can obtain the target signal e from the acoustic feedback cancellation unit 151 on the one hand, and obtain the signal n2 from the second audio component 300 on the other hand. The gain amplification unit 152 can perform gain amplification processing on the target signal e and the signal n2, as well as appropriate mixing and superposition calculations to obtain the second audio signal u. It can be seen that in this case, part of the signal components in the second audio signal u come from the target signal e, and the other part of the signal components come from the second audio component 300.

[0085] Those skilled in the art will appreciate that, in practical applications, the above-mentioned Figures 3B and 3C can be combined with each other. For example, the acoustic system includes both a first audio component 200 and a second audio component 300, both of which are connected to the gain amplification unit 152. The first audio component 200 provides a signal n1 to the gain amplification unit 152, the second audio component 300 provides a signal n2 to the gain amplification unit 152, and the acoustic feedback cancellation unit 151 provides a target signal e to the gain amplification unit 152. In this case, the gain amplification unit 152 performs gain amplification processing on the target signal e, the signal n1, and the signal n2, and performs appropriate mixing and superposition calculations to obtain the second audio signal u. In this case, part of the signal components in the second audio signal u come from the target signal e, part of the signal components come from the first audio component 200, and the other part of the signal components come from the second audio component 300.

[0086] 3A to 3C , a reference signal collecting point 133 may exist in the first peripheral circuit 130. The signal flowing through the reference signal collecting point 133 in the first peripheral circuit 130 may be referred to as a first reference signal u′.

[0087] In some embodiments, the first reference signal u′ may be a temporally continuous signal. In some embodiments, the first reference signal u′ may be a temporally discrete signal. In some embodiments, the first reference signal u′ may be a signal modulated by one or more modulation techniques. In some embodiments, the first reference signal u′ may be an unmodulated signal. In some embodiments, the first reference signal u′ may be a mono signal. In some embodiments, the first reference signal u′ may be a binaural signal. In some embodiments, the first reference signal u′ may be a signal formed by overlapping multi-channel signals. In some embodiments, the first reference signal u′ may be a signal that can directly drive the speaker 110 to produce sound. In some embodiments, the first reference signal u′ may be a signal that cannot directly drive the speaker 110 to produce sound, and can only drive the speaker 110 to produce sound after being modulated.

[0088] For example, the signal type (signal format / format) of the first reference signal u′ includes at least one of the following (1) to (6).

[0089] (1) Analog signal. An analog signal is a signal represented by a continuously changing physical quantity, whose amplitude, frequency, or phase changes continuously with time, or whose characteristic quantity representing information can be presented as any value at any moment within a continuous time interval.

[0090] (2) Pulse Width Modulation (PWM) signal. PWM signals are signals modulated using pulse width modulation technology. Pulse width modulation modulates the width of a series of pulses to produce the desired waveform and digitally encodes the analog signal level.

[0091] (3) Pulse Density Modulation (PDM) signal. A PDM signal is a signal modulated using pulse density modulation technology. Pulse density modulation is a modulation method that uses binary numbers 0 and 1 to represent analog signals. In a PDM signal, the amplitude of the analog signal is represented by the density of the area corresponding to the output pulse. For example, in some pulse density modulation methods, the data stream corresponding to the PDM signal only contains 1s and 0s. The greater the density of 1s, the greater the amplitude of the analog signal corresponding to the area. Conversely, the greater the density of 0s, the smaller the amplitude of the analog signal corresponding to the area.

[0092] (4) Pulse Code Modulation (PCM) signal. PCM refers to a signal modulated using pulse code modulation technology. The pulse code modulation process is as follows: the analog signal is first sampled at regular intervals to discretize it, and then the discretized sample values ​​are quantized and encoded to produce the PCM signal. PCM can be considered a monophonic signal.

[0093] (5) Integrated circuit built-in audio I2S (Inter-IC Sound) signal. I2S signal refers to the signal transmitted based on the I2S bus. I2S signal can be regarded as a signal composed of two-channel PCM signals interwoven.

[0094] (6) Time-division multiplexing (TDM) signal. A TDM signal is a signal obtained by interleaving multiple signals using time-division multiplexing technology. For example, a TDM signal can be a signal obtained by interleaving multiple channels of PCM signals using time-division multiplexing technology.

[0095] Among the aforementioned signal types, analog signals, PWM signals, and some PDM signals can directly drive the speaker 110. However, PCM signals, I2S signals, TDM signals, and some other PDM signals cannot directly drive the speaker 110 and must first be demodulated and decoded before driving the speaker 110. Except for analog signals, the other signal types (PWM signals, PDM signals, PCM signals, I2S signals, and TDM signals) can all be considered modulated signals.

[0096] Those skilled in the art will appreciate that the signal types listed above are only some possible examples, and with the evolution and development of technology, the signal type of the first reference signal u′ may also be any other possible type.

[0097] It should be noted that the reference signal pickup point 133 may be located at any position in the first peripheral circuit 130, and the embodiments of this specification do not limit this. The following examples illustrate the location of the reference signal pickup point 133 in conjunction with several possible implementations.

[0098] In some embodiments, the reference signal pickup point 133 may be located at the input port 131, that is, no circuit elements exist between the input port 131 and the reference signal pickup point 133. In this case, the first reference signal u′ at the reference signal pickup point 133 is the same as the second audio signal u.

[0099] In some embodiments, the reference signal pickup point 133 may be located at the output port 132, that is, no circuit elements exist between the reference signal pickup point 133 and the output port 132. In this case, the first reference signal u′ at the reference signal pickup point 133 is the same as the drive signal u″′.

[0100] In some embodiments, the reference signal pickup point 133 may be located somewhere between the input port 131 and the output port 132. That is, there is at least one circuit element between the input port 131 and the reference signal pickup point 133, and there is also at least one circuit element between the reference signal pickup point 133 and the output port 132. In other words, the reference signal pickup point 133 may divide the first peripheral circuit 130 into a first circuit portion and a second circuit portion. The first circuit portion refers to the circuit portion located between the input port 131 and the reference signal pickup point 133, and the second circuit portion refers to the circuit portion located between the reference signal pickup point 133 and the output port 132. Neither the first circuit portion nor the second circuit portion is empty. In this case, the first reference signal u′ at the reference signal pickup point 133 is a signal after the first circuit portion performs preset processing on the second audio signal u. The first reference signal u′ is different from the second audio signal u, and the first reference signal u′ is also different from the drive signal u″′.

[0101] For example, referring again to Figures 3A to 3C , the first peripheral circuit 130 may include a first processing component 134 (labeled DA in the figures). The first processing component 134 is connected to the signal processing circuit 150 via the input port 131. When in operation, the first processing component 134 obtains a second audio signal u from the signal processing circuit 150 and performs at least one of a digital-to-analog conversion operation, a modulation operation, and a filtering operation on the second audio signal u.

[0102] The first processing component 134 may include one or more circuit elements, and the embodiments of this specification do not limit this. Some examples are given below. For example, the first processing component 134 may include a circuit element, and the circuit element may perform at least one of the above-mentioned digital-to-analog conversion operation, modulation operation, and filtering operation. For another example, the first processing component 134 may include three circuit elements, wherein the first circuit element performs the digital-to-analog conversion operation, the second circuit element performs the modulation operation, and the third circuit element performs the filtering operation. For another example, the first processing component 134 may include two circuit elements, wherein the first circuit element performs the digital-to-analog conversion operation and the modulation operation, and the second circuit element performs the filtering operation. It should be noted that the above examples are only for ease of understanding and do not limit the embodiments of this specification.

[0103] 3A to 3C , when the first peripheral circuit 130 includes the first processing component 134, the reference signal pickup point 133 may be located between the first processing component 134 and the output port 132. In other words, the reference signal pickup point 133 may be located anywhere in the signal path after the first processing component 134.

[0104] In some cases, the first peripheral circuit 130 includes no other components except the first processing component 134. In this case, the reference signal pickup point 133 can be set after the first processing component 134, which can also be regarded as the reference signal pickup point 133 being located at the output port 132.

[0105] In other cases, the first peripheral circuit 130 may include, in addition to the first processing component 134, a second processing component 135. The second processing component 135 is connected between the first processing component 134 and the output port 132. The second processing component 135 may be configured to perform at least one of a filtering operation, a gain operation, or other possible operations. The second processing component 135 may include one circuit element or multiple circuit elements. The position of the reference signal pickup point 133 in this case is illustrated below with reference to Figures 4A to 4C.

[0106] Figures 4A to 4C show schematic diagrams of several locations of the reference signal pickup point 133 in the acoustic system. In some embodiments, referring to Figure 4A, the reference signal pickup point 133 can be located between the first processing component 134 and the second processing component 135. In some embodiments, referring to Figure 4B, the reference signal pickup point 133 can be located between the second processing component 135 and the output port 132. In some embodiments, when the second processing component 135 includes multiple circuit elements, the reference signal pickup point 133 can be located between any two of the multiple circuit elements. Figure 4C illustrates an example in which the second processing component 135 includes two circuit elements 135-1 and 135-2. Referring to Figure 4C, the reference signal pickup point 133 can be located between circuit element 135-1 and circuit element 135-2. It should be noted that Figures 4A to 4C are only some possible examples. In addition to Figures 4A to 4C, the location of the reference signal pickup point 133 can also be set in other ways. Those skilled in the art will appreciate that the reference signal pickup point location schemes shown in FIG. 4A to FIG. 4C can be applied to the acoustic system shown in FIG. 3A , the acoustic system shown in FIG. 3B , and the acoustic system shown in FIG. 3C .

[0107] 3A to 3C are described using the example that the first peripheral circuit 130 includes only one input port 131 . In some cases, the first peripheral circuit 130 may include multiple input ports, each of which may be configured to receive a signal source for driving the speaker 110 .

[0108] For ease of description, it is assumed that the input port 131 of the first peripheral circuit 130 includes K branch ports, namely 131-1, 131-2, ..., 131-K. K is an integer greater than 1. In this case, the first peripheral circuit 130 can obtain the branch audio signal u1 through the branch port 131-1, obtain the branch audio signal u2 through the branch port 131-2, and so on, obtain the branch audio signal u1 through the branch port 131-K. K In this case, the first peripheral circuit 130 obtains K branch audio signals through the K branch ports, converts the K branch audio signals into driving signals u″′, and sends the driving signals u″′ to the speaker 110 through the output port 132 .

[0109] In some embodiments, the branch audio signals obtained by the first peripheral circuit 130 through the K branch ports may all come from the target signal e.

[0110] The phrase "the branch audio signal is derived from the target signal e" may include the following two situations: Scenario 1: The branch audio signal and the target signal e are the same signal; Scenario 2: The branch audio signal is obtained by performing a predetermined processing on the target signal e. The predetermined processing may include one or more of gain amplification, frequency division, filtering, or other possible processing methods.

[0111] Figure 5A shows a connection scenario for the K branch ports of the first peripheral circuit 130 in the acoustic system. Figure 5A illustrates the above-mentioned scenario 2. Take K=2 as an example. As shown in Figure 5A, the signal processing circuit 150 includes an acoustic feedback cancellation unit 151 and a gain amplification unit 152. The branch ports 131-1 and 131-2 in the first peripheral circuit 130 are both connected to the gain amplification unit 152. The acoustic feedback cancellation unit 151 processes the first audio signal y to reduce the feedback component in the first audio signal y, thereby obtaining the target signal e. The gain amplification unit 152 performs gain amplification processing on the target signal e to obtain a branch audio signal u1 and a branch audio signal u2. In this way, the first peripheral circuit 130 can obtain the branch audio signal u1 through the branch port 131-1 and the branch audio signal u2 through the branch port 131-2. In this case, both the branch audio signal u1 and the branch audio signal u2 are signals obtained by processing the target signal e. Therefore, both the branch audio signal u1 and the branch audio signal u2 are derived from the target signal e.

[0112] In some embodiments, the K branch ports may include a first portion of branch ports and a second portion of branch ports, wherein the branch audio signals obtained by the first peripheral circuit 130 through the first portion of branch ports are from the target signal e, and the branch audio signals obtained by the first peripheral circuit 130 through the second portion of branch ports are from the target audio component.

[0113] The target audio component is another component having an audio output function that is different from the sound pickup component 20. The target audio component may be a component integrated into the signal processing circuit 150 or a component external to the signal processing circuit 150 (for example, the target audio component may be integrated into another circuit in the acoustic system other than the signal processing circuit 150, or may be another external acoustic device).

[0114] For example, in some embodiments, the target audio component may be a Bluetooth component, which may be integrated within the signal processing circuit 150 or may be integrated into other circuit systems. The Bluetooth component may receive Bluetooth audio signals from an external acoustic device. In some embodiments, the target audio component may be a codec component built into the signal processing circuit 150, which may decode the built-in audio to generate a prompt tone. In some embodiments, the target audio component may also be other external components / external devices connected to the acoustic system by wire.

[0115] Figure 5B shows another connection situation of the K branch ports of the first external circuit 130 in the acoustic system. Figure 5B takes K=2 as an example. As shown in Figure 5B, the signal processing circuit 150 includes an acoustic feedback cancellation unit 151, a gain amplification unit 152 and a first audio component 200 (marked as Y1 in the figure). Among them, the branch port 131-1 in the first peripheral circuit 130 is connected to the gain amplification unit 152, and the branch port 131-2 is connected to the first audio component 200. The acoustic feedback cancellation unit 151 processes the first audio signal y to reduce the feedback component in the first audio signal y, thereby obtaining the target signal e. The gain amplification unit 152 performs gain amplification processing on the target signal e to obtain a branch audio signal u1, and outputs the branch audio signal u1 to the branch port 131-1. The first audio component 200 outputs the branch audio signal u2 to the branch port 131-2. In this way, the first peripheral circuit 130 can obtain the branch audio signal u1 through the branch port 131-1 and the branch audio signal u2 through the branch port 131-2. In this case, the branch audio signal u1 is a signal obtained by processing the target signal e, that is, the branch audio signal u1 comes from the target signal e, and the branch audio signal u2 comes from the first audio component 200.

[0116] Figure 5C shows another connection scenario for the K branch ports of the first external circuit 130 in the acoustic system. Figure 5C takes K=2 as an example. As shown in Figure 5C, the signal processing circuit 150 includes an acoustic feedback cancellation unit 151 and a gain amplification unit 152. The acoustic system also includes a second audio component 300 (labeled as Y2 in the figure), which is located outside the signal processing circuit 150. Branch port 131-1 in the first external circuit 130 is connected to the gain amplification unit 152, and branch port 131-2 is connected to the second audio component 300. The acoustic feedback cancellation unit 151 processes the first audio signal y to reduce the feedback component in the first audio signal y, thereby obtaining the target signal e. The gain amplification unit 152 performs gain amplification on the target signal e to obtain a branch audio signal u1, and outputs the branch audio signal u1 to the branch port 131-1. The second audio component 300 outputs the branch audio signal u2 to the branch port 131-2. In this way, the first peripheral circuit 130 can obtain the branch audio signal u1 through the branch port 131-1 and the branch audio signal u2 through the branch port 131-2. In this case, the branch audio signal u1 is a signal obtained by processing the target signal e, that is, the branch audio signal u1 comes from the target signal e, and the branch audio signal u2 comes from the second audio component 300.

[0117] Those skilled in the art will appreciate that, in practical applications, FIG. 5B and FIG. 5C can be combined. For example, the acoustic system may include both a first audio component 200 and a second audio component 300. The first audio component 200 is located inside the signal processing circuit 150, and the second audio component 300 is located outside the signal processing circuit 150. Both are connected to the branch port in the first peripheral circuit 130. In this case, among the multiple branch audio signals received by the first peripheral circuit 130, some of the branch audio signals come from the target signal e, some of the branch audio signals come from the first audio component 200, and some of the branch audio signals come from the second audio component 300.

[0118] In the case where the first peripheral circuit 130 includes multiple branch ports (as shown in Figures 5A to 5C), the following describes the location of the reference signal pickup point 133 with reference to several examples. The following examples are based on the example of the first peripheral circuit 130 including two branch ports.

[0119] Figure 6A shows a schematic diagram of the location of the reference signal pickup point 133. As shown in Figure 6A, the first peripheral circuit 130 may include a third processing component 136 (marked as DA in the figure). The third processing component 136 obtains the branch audio signal u1 from the branch port 131-1 and the branch audio signal u2 from the branch port 131-2, and performs at least one of a digital-to-analog conversion operation, a modulation operation, a filtering operation, and a stream mixing operation on the above two branch audio signals. It should be noted that the third processing component 136 may include one or more circuit elements, and the embodiments of this specification are not limited to this. In this case, the reference signal pickup point 133 can be located between the third processing component 136 and the output port 132.

[0120] In some cases, the first peripheral circuit 130 includes no other components except the third processing component 136. In these cases, the reference signal pickup point 133 can be set at a position after the third processing component 136, which can also be regarded as the reference signal pickup point 133 being located at the output port 132. In other cases, the first peripheral circuit 130 may include a second processing component 135 in addition to the third processing component 136. The second processing component 135 is connected between the third processing component 136 and the output port 132. The second processing component 135 can be configured to perform at least one of a filtering operation, a gain operation, or other possible operations. The second processing component 135 may include one circuit element or multiple circuit elements. In this case, the position of the reference signal pickup point 133 can be similar to that in Figures 4A to 4C, and will not be described in detail here.

[0121] Figure 6B shows a schematic diagram of the location of the reference signal pickup point 133. As shown in Figure 6B, the first peripheral circuit 130 may include two branch processing components 137-1 and 137-2 (labeled DA1 and DA2 in the figure, respectively, where DA1 and DA2 can perform the same operation or different operations to process the same or different signals) and a first mixing component 138 (labeled C in the figure). The branch processing component 137-1 is connected to the branch port 131-1. During operation, it obtains the branch audio signal u1 from the branch port 131-1 and performs at least one of a digital-to-analog conversion operation, a modulation operation, and a filtering operation on the branch audio signal u1 to obtain an intermediate audio signal u′1. The branch processing component 137-2 is connected to the branch port 131-2. During operation, it obtains the branch audio signal u2 from the branch port 131-2 and performs at least one of a digital-to-analog conversion operation, a modulation operation, and a filtering operation on the branch audio signal u2 to obtain an intermediate audio signal u′2. The first mixing component 138 is connected to the branch processing components 137 - 1 and 137 - 2 respectively, and performs mixing operations on the intermediate audio signals u′ 1 and u′ 2 during operation. In this case, the reference signal pickup point 133 can be located between the first mixing component 138 and the output port 132 .

[0122] In some cases, the first peripheral circuit 130 includes no other components besides the branch processing component 137-1, the branch processing component 137-2, and the first mixing component 138. In these cases, the reference signal pickup point 133 can be set at a position after the first mixing component 138, which can also be regarded as the reference signal pickup point 133 being located at the output port 132. In other cases, the first peripheral circuit 130 may include, in addition to the branch processing components 137-1, 137-2, and the first mixing component 138, a second processing component 135. For example, the second processing component 135 may be connected between the first mixing component 138 and the output port 132. The second processing component 135 may be configured to perform at least one of a filtering operation, a gain operation, or other possible operations. The second processing component 135 may include one circuit element or multiple circuit elements. In this case, the position of the reference signal pickup point 133 may be similar to that in Figures 4A to 4C and will not be described in detail here.

[0123] Figures 6C and 6D show schematic diagrams of several locations of the reference signal pickup point 133. As shown in Figures 6C and 6D, the first peripheral circuit 130 may include a second mixing component 139 (labeled C in the drawings) and a fourth processing component 141 (labeled DA in the drawings). The second mixing component 139 is connected to branch ports 131-1 and 131-2, respectively. The second mixing component 139 obtains a branch audio signal u1 from branch port 131-1 and a branch audio signal u2 from branch port 131-2, and performs a mixing operation on the branch audio signals u1 and u2 to obtain a mixed audio signal. The fourth processing component 141 is connected to the second mixing component 139. The fourth processing component 141 performs at least one of a digital-to-analog conversion operation, a modulation operation, and a filtering operation on the mixed audio signal. In this case, the reference signal pickup point 133 may be located between the second mixing component 139 and the output port 132. 6C , the reference signal pickup point 133 may be located between the second mixing component 139 and the fourth processing component 141 . For example, referring to FIG6D , the reference signal pickup point 133 may be located between the fourth processing component 141 and the output port 132 .

[0124] In some cases, the first peripheral circuit 130 includes no other components besides the second mixing component 139 and the fourth processing component 141. In these cases, the reference signal pickup point 133 can be set at a position after the fourth processing component 141, which can also be regarded as the reference signal pickup point 133 being located at the output port 132. In other cases, the first peripheral circuit 130 may include, in addition to the second mixing component 139 and the fourth processing component 141, a second processing component 135. The second processing component 135 is connected between the fourth processing component 141 and the output port 132. The second processing component 135 can be configured to perform at least one of a filtering operation, a gain operation, or other possible operations. The second processing component 135 may include one circuit element or multiple circuit elements. In this case, the reference signal pickup point 133 can be located at any position after the fourth processing component 141. The specific implementation is similar to that of Figures 4A to 4C and will not be described in detail here.

[0125] Those skilled in the art will appreciate that FIG. 6A to FIG. 6D only illustrate partial circuits in the acoustic system, and these partial circuits can be applied to the acoustic system shown in FIG. 5A or the acoustic system shown in FIG. 5B .

[0126] According to an embodiment of the present specification, the acoustic system may further include a second peripheral circuit 170 (marked as C2 in the accompanying drawings). As shown in Figures 3A to 3C and Figures 5A to 5C, the second peripheral circuit 170 is connected between the reference signal pickup point 133 and the signal processing circuit 150. Specifically, the input end of the second peripheral circuit 170 is connected to the reference signal pickup point 133, and the output end is connected to the signal processing circuit 150. When the second peripheral circuit 170 is running, it obtains a first reference signal u′ from the reference signal pickup point 133, converts the first reference signal u′ into a second reference signal u″, and outputs the second reference signal u″ to the signal processing circuit 150.

[0127] The second reference signal u″ is a digital signal, that is, a signal that can be directly used by the signal processing circuit 150 to perform mathematical operations, and is usually located in the memory or cache of the signal processing circuit 150 or in the cache of the edge device. In the embodiment of this specification, the second reference signal u″ is used to simulate the signal at the speaker 110. For example, the second reference signal u″ can be made equal to or approximately equal to the driving signal u″′ of the speaker 110.

[0128] Because the first reference signal u′ is obtained from the reference signal pickup point 133 in the first peripheral circuit 130, the first reference signal u′ can be considered an intermediate signal obtained after the first circuit portion of the first peripheral circuit 130 performs a preset operation on the second audio signal u. Therefore, after obtaining the first reference signal u′, the second peripheral circuit 170 can perform certain operations (such as the inverse or opposite operation corresponding to the preset operation) on the first reference signal u′ so that the obtained second reference signal u″ closely resembles the signal at the speaker 110.

[0129] In some embodiments, the second peripheral circuit 170 may perform at least one of an analog-to-digital conversion operation, a demodulation operation, a filtering operation, and a gain operation on the first reference signal u′ to obtain a second reference signal u″. Those skilled in the art will appreciate that the specific operations performed by the second peripheral circuit 170 on the first reference signal u′ are related to the operations performed by the first circuit portion of the first peripheral circuit 130 on the second audio signal u, and / or are related to the signal type of the first reference signal u′. Several possible examples of implementations of the second peripheral circuit 170 are provided below.

[0130] For example, the first reference signal u′ is a continuous analog signal. In this case, in some possible implementations, the second peripheral circuit 170 may perform an analog-to-digital conversion operation on the first reference signal u′ to obtain the second reference signal u″.

[0131] For example, the first reference signal u′ is a PWM signal. In this case, in some possible implementations, the second peripheral circuit 170 may first perform a filtering operation on the first reference signal u′ to remove high-frequency carrier components therein, and then perform an analog-to-digital conversion operation on the filtered signal to obtain the second reference signal u″.

[0132] For example, the first reference signal u′ is a PDM signal. In this case, in some possible implementations, the second peripheral circuit 170 may first perform a filtering operation on the first reference signal u′ to filter out the high-frequency carrier component therein, and then perform an analog-to-digital conversion operation on the filtered signal to obtain the second reference signal u″. In addition, in some cases, the signal processing circuit 150 may directly receive and decode the PDM signal through the GPIO digital port. In this case, the second peripheral circuit 170 may perform either a filtering operation or an analog-to-digital conversion operation on the first reference signal u′, or may not perform both of the above operations.

[0133] For another example, the first reference signal u′ is a PCM signal, an I2S signal, or a TDM signal. In some possible implementations, the second peripheral circuit 170 may perform a demodulation operation.

[0134] It should be noted that the above examples are only provided for ease of understanding and should not be construed as limiting the embodiments of this specification. Those skilled in the art will appreciate that the second peripheral circuit 170 may be implemented in a variety of other ways, which are not listed in this specification.

[0135] The second peripheral circuit 170 may include one or more circuit elements, and the embodiments of this specification do not limit this. Some examples are given below. For example, the second peripheral circuit 170 may include a circuit element, and the circuit element may perform at least one of an analog-to-digital conversion operation, a demodulation operation, a filtering operation, and a gain operation. For another example, the second peripheral circuit 170 may include two circuit elements, one of which performs an analog-to-digital conversion operation, and the other performs a demodulation operation. For another example, the second peripheral circuit 170 may include three circuit elements, a first circuit element performs an analog-to-digital conversion operation and a demodulation operation, a second circuit element performs a filtering operation, and a third circuit element performs a gain operation. It should be noted that the above examples are only for ease of understanding and do not limit the embodiments of this specification.

[0136] The following describes the process of canceling feedback components of the acoustic system provided in this specification in conjunction with Figure 3A. It should be noted that the process of canceling feedback components of the acoustic systems shown in Figures 3B, 3C, 5A, 5B, and 5C is similar and will not be described in detail in this specification.

[0137] Referring to Figure 3A, the working process of the acoustic system is as follows: the first peripheral circuit 130 obtains the second audio signal u from the signal processing circuit 150 through the input port 131, converts the second audio signal u into a driving signal u″′, and sends the driving signal u″′ to the speaker 110 through the output port 132. The speaker 110 converts the driving signal u″′ into a first sound. The target sound source 160 emits a second sound. The sound sensor 120 collects the ambient sound and converts the ambient sound into a pickup signal y′, the third peripheral circuit 140 converts the pickup signal y′ into a first audio signal y, and outputs the first audio signal y to the signal processing circuit 150. The second peripheral circuit 170 obtains the first reference signal u′ from the reference signal pickup point 133, converts the first reference signal u′ into a second reference signal u″, and outputs the second reference signal u″ to the signal processing circuit 150.

[0138] After the signal processing circuit 150 obtains the first audio signal y from the third peripheral circuit 140 and the second reference signal u″ from the second peripheral circuit 170, the second reference signal u″ is applied to the AFC technology. That is, the signal processing circuit 150 can reduce the signal component corresponding to the first sound in the first audio signal y based on the second reference signal u″ to obtain the target signal e.

[0139] Specifically, referring to FIG3A , the signal processing circuit 150 may include an acoustic feedback cancellation unit 151. The input of the acoustic feedback cancellation unit 151 includes: a first audio signal y and a second reference signal u″. The acoustic feedback cancellation unit 151 can solve and adaptively update a time-varying transfer function F′ to fit the real transfer function F corresponding to the feedback path (i.e., the transmission path of the feedback sound). The acoustic feedback cancellation unit 151 uses the predicted transfer function F′ to perform an adaptive filtering operation on the second reference signal u″ to obtain a signal x′, i.e., x′=u″*F′. The signal x′ can be regarded as a predicted value of the feedback component in the first audio signal y (i.e., the signal component in the first audio signal y corresponding to the first sound). Furthermore, the acoustic feedback cancellation unit 151 can subtract the signal x′ from the first audio signal y to obtain a target signal e, i.e., e=y-x'. The target signal e obtained in this way does not contain or contains less feedback components.

[0140] After obtaining the target signal e, the signal processing circuit 150 may also update the filtering parameters of the adaptive filtering operation based on at least one of the second reference signal u″ and the target signal e, that is, update the predicted transfer function F′. Specifically, according to the theory of the adaptive filtering algorithm, the update method of the predicted transfer function F′ can be achieved by minimizing the expectation of the mean square function of the target signal e, that is: min F′ E[e 2 ]=min F′E[(yu″*F′) 2 ] Formula (1-2)

[0141] Still taking the acoustic feedback cancellation unit 170 using the LMS algorithm as an example, the above formula (1-2) is derived based on the gradient descent optimization method, and the update formula of the predicted transfer function F′ can be obtained as follows: F′←F′+μ*e*u″ Formula (2-2)

[0142] Where μ is the iteration step size.

[0143] It should be understood that when the acoustic feedback cancellation unit 170 adopts algorithms such as NLMS, RLS, etc., a similar method can be used to derive an update formula for the predicted transfer function F′, which will not be explained one by one in this specification.

[0144] After the acoustic system shown in FIG3A obtains the target signal e, the signal processing circuit 150 can perform a target operation on the target signal e. Continuing with FIG3A , the signal processing circuit 150 can further include a gain amplification unit 152 (labeled G in FIG3A ). The gain amplification unit 152 amplifies the target signal e and transmits the amplified signal as the second audio signal u at the next moment to the first peripheral circuit 130, thereby driving the speaker 110 to produce sound.

[0145] In summary, the acoustic system provided in this specification sets a reference signal pickup point 133 in the first peripheral circuit 130 and sets a second peripheral circuit 140 between the reference signal pickup point 133 and the signal processing circuit 150, so that the second peripheral circuit 140 can obtain the first reference signal u′ from the reference signal pickup point 133 and convert the first reference signal u′ into a second reference signal u″. Thus, the signal processing circuit 150 can apply the second reference signal u″ to the AFC technology, that is, the signal processing circuit 150 can reduce the feedback component in the first audio signal y based on the second reference signal u″ to obtain the target signal e. Since the feedback component in the target signal e is reduced or eliminated, the howling of the acoustic system can be avoided or suppressed, and it also helps to improve the maximum forward gain that can be achieved by the acoustic system.

[0146] Since the acoustic feedback cancellation unit 151 can obtain the second reference signal u″ through the electrical space (i.e., the first peripheral circuit 130 and the second peripheral circuit 170) and use it for the AFC technology, it is no longer necessary to obtain the second audio signal u from other units within the signal processing circuit 150. Therefore, even if there are access restrictions between different units within the signal processing circuit 150, the acoustic system can use the AFC technology to cancel the feedback component, thereby improving the wide application of the AFC technology.

[0147] In the scheme shown in FIG3A , after the signal processing circuit 150 obtains the second reference signal u″ from the electrical space, there is no need to change the internal implementation of the acoustic feedback cancellation unit 151, that is, there is no need to change the update formula of the predicted transfer function F′ and the calculation formula for feedback component cancellation. Instead, it is only necessary to replace the input signal u of the acoustic feedback cancellation unit 151 with u″. It can be seen that the acoustic system shown in FIG3A can be applied, adapted, and compatible with the existing acoustic feedback cancellation unit 151, with low modification difficulty and wide applicability.

[0148] Furthermore, in some embodiments, at least one circuit element in the first processing component 134 exhibits a nonlinear response. The nonlinear response refers to the output signal S of the circuit element. out With the input signal S in If the output signal S of circuit element A is out With the input signal S in If the output signal S of circuit element A is linear, it means that circuit element A has a linear response. out With the input signal S in If there is a nonlinear relationship between them, it means that circuit element A exhibits a nonlinear response. For example, during the design phase of the acoustic system, one or more target components in the first peripheral circuit 130 that have nonlinear responses can be pre-calculated and used as the first processing component 134. The reference signal pickup point 130 is set after the first processing component 134.

[0149] In the solution shown in FIG3A , because reference signal pickup point 133 is located after first processing component 134, predicted transfer function F′ actually fits the transfer characteristics of the second circuit portion, speaker 110, the spatial path between speaker 110 and sound sensor 120, sound sensor 120, and third peripheral circuit 140. Therefore, predicted transfer function F′ no longer needs to fit the transfer characteristics of the first circuit portion (i.e., first processing component 134). Consequently, the nonlinear response of the first circuit portion is not introduced into the iterative solution of predicted transfer function F′, reducing its impact on the convergence performance of the adaptive filtering algorithm and thereby improving the effectiveness of eliminating feedback components.

[0150] FIG7 illustrates the test results of the filtering performance of an acoustic system provided according to an embodiment of this specification. Using the acoustic system shown in FIG3A as the test object, referring to FIG7 , when the scheme shown in FIG2 is employed, and the first processing component 134 has a limiting characteristic, the calculated misalignment (MIS) is shown in Curve A. When the scheme shown in FIG3A is employed, the calculated misalignment (MIS) is shown in Curve B. The method for calculating the misalignment has been described previously and will not be repeated here. In FIG7 , Curve B decreases more rapidly than Curve A during the rapid convergence period and maintains a relatively rapid average downward trend during the stable convergence period. In other words, Curve B remains below Curve A throughout the illustrated time periods. Therefore, the misalignment MIS of the scheme shown in FIG3A is consistently lower than that of the scheme shown in FIG2 , indicating that the scheme shown in FIG3A outperforms the scheme shown in FIG2 in terms of both the degree of convergence and the speed of convergence of the adaptive filtering algorithm. FIG7 : As can be seen from FIG3A , the convergence degree and speed of the adaptive filtering algorithm are significantly improved.

[0151] The signal processing circuit 150 can be configured to execute the signal processing method described in the embodiments of this specification. In some embodiments, the signal processing circuit 150 may include multiple hardware circuits with a connection relationship, each hardware circuit includes one or more electrical components, and implements one or more steps of the signal processing method described in the embodiments of this specification when working. For example, the acoustic feedback cancellation unit 151 and the gain amplification unit 152 can be implemented by different hardware circuits or different electrical components respectively. The above-mentioned multiple hardware circuits cooperate with each other to implement the signal processing method described in the embodiments of this specification when working. In some embodiments, the signal processing circuit 150 may also include a hardware device with a data information processing function and the necessary program required to drive the hardware device to work, and the hardware device implements the signal processing method described in the embodiments of this specification by executing the program. The signal processing method will be described in detail in the following content.

[0152] FIG8 shows a schematic diagram of a hardware structure of an acoustic system provided according to an embodiment of the present specification. As shown in FIG8 , the signal processing circuit 150 may include: at least one storage medium 210 and at least one processor 220. The at least one processor 220 is in communication with the sound producing component 10 and the sound pickup component 20. It should be noted that, for the purpose of demonstration only, the signal processing circuit 150 in the embodiment of the present specification includes at least one storage medium 210 and at least one processor 220. It will be understood by those skilled in the art that the signal processing circuit 150 may also include other hardware circuit structures, which are not limited in the embodiments of the present specification, as long as they can meet the functions mentioned in the embodiments of the present specification without departing from the spirit of the embodiments of the present specification.

[0153] Continuing with FIG8 , in some embodiments, the acoustic system may further include a communication port 230. The communication port 230 is used for data communication between the acoustic system and the outside world. For example, the communication port 230 can be used for data communication between the acoustic system and other devices / systems. In some embodiments, the acoustic system may further include an internal communication bus 240. The internal communication bus 240 can connect different system components. For example, the sound generating component 10, the sound pickup component 20, the processor 220, the storage medium 210, and the communication port 230 can all be connected via the internal communication bus 240.

[0154] The storage medium 210 may include a data storage device. The data storage device may be a non-transitory storage medium or a temporary storage medium. For example, the data storage device may include one or more of a disk 2101, a read-only storage medium (ROM) 2102, or a random access storage medium (RAM) 2103. The storage medium 210 also includes at least one instruction set stored in the data storage device. The instruction set includes instructions, which are computer program codes. The computer program codes may include programs, routines, objects, components, data structures, processes, modules, etc. for executing the signal processing methods provided in the embodiments of this specification.

[0155] At least one processor 220 is used to execute the at least one instruction set mentioned above. When the acoustic system is running, at least one processor 220 reads the at least one instruction set and, according to the instructions of the at least one instruction set, executes the signal processing method provided by the embodiment of this specification. The processor 220 can perform all or part of the steps included in the above-mentioned signal processing method. The processor 220 can be in the form of one or more processors. In some embodiments, the processor 220 can include one or more hardware processors, such as a microcontroller, a microprocessor, a reduced instruction set computer (RISC), an application-specific integrated circuit (ASIC), an application-specific instruction set processor (ASIP), a central processing unit (CPU), a graphics processing unit (GPU), a physical processing unit (PPU), a microcontroller unit, a digital signal processor (DSP), a field programmable gate array (FPGA), an advanced RISC machine (ARM), a programmable logic device (PLD), any circuit or processor capable of performing one or more functions, etc., or any combination thereof. For illustration purposes only, the acoustic system shown in Figure 8 illustrates a case where only one processor 220 is included. However, it should be noted that the acoustic system provided in the embodiments of this specification may also include multiple processors. Therefore, the operations and / or method steps disclosed in the embodiments of this specification may be performed by a single processor or jointly by multiple processors. For example, if the processor 220 of the acoustic system in the embodiments of this specification performs step A and step B, it should be understood that step A and step B may also be performed jointly or separately by two different processors 220 (e.g., the first processor performs step A, the second processor performs step B, or the first and second processors perform steps A and B together).

[0156] FIG9 shows a flow chart of a signal processing method P100 provided according to an embodiment of the present specification. As previously described, the signal processing circuit 150 in the acoustic system can execute the signal processing method P100 of the present specification. Specifically, the processor 220 can read the instruction set stored in its local storage medium and then execute the signal processing method P100 of the present specification according to the provisions of the instruction set. As shown in FIG9 , the signal processing method P100 may include:

[0157] S10: Obtain a first audio signal, where the first audio signal is obtained by converting ambient sound by a sound pickup component in an acoustic system. The ambient sound includes a first sound and a second sound. The first sound is sound from a speaker in the acoustic system, and the second sound is sound from a target sound source.

[0158] S20: Obtain a second reference signal, where the second reference signal is obtained by a second peripheral circuit in the acoustic system based on a first reference signal, wherein the first reference signal is obtained by the second peripheral circuit from a reference signal pickup point of a first peripheral circuit in the acoustic system, and the first peripheral circuit is connected to the signal processor and the speaker.

[0159] It should be understood that the execution order of S10 and S20 can be arbitrary. For example, the signal processing circuit 150 can execute S10 first and then S20, or can execute S20 first and then S10, or can execute S10 and S20 in parallel.

[0160] S30: Based on the second reference signal, reduce the signal component corresponding to the first sound in the first audio signal to obtain a target signal.

[0161] S40: performing a target operation on the target signal.

[0162] In some embodiments, the type of the first reference signal includes at least one of an analog signal, a pulse width modulation PWM signal, a pulse density modulation PDM signal, a pulse code modulation PCM signal, an integrated circuit built-in audio I2S signal, or a time division multiplexing TDM signal.

[0163] In some embodiments, based on the second reference signal, reducing the signal component corresponding to the first sound in the first audio signal to obtain a target signal includes: performing an adaptive filtering operation on the second reference signal to obtain a filtered signal; and subtracting the filtered signal from the first audio signal to obtain the target signal.

[0164] In some embodiments, the method further includes: updating filtering parameters corresponding to the adaptive filtering operation based on at least one of the target signal and the second reference signal.

[0165] It should be noted that the detailed implementation of the signal processing method P100 can be found in the relevant description of the acoustic system above. Its implementation principle and technical effects are similar and will not be repeated here.

[0166] To sum up, in the solution provided in this specification, the acoustic system sets a reference signal pickup point 133 in the first peripheral circuit 130, and sets a second peripheral circuit 140 between the reference signal pickup point 133 and the signal processing circuit 150, so that the second peripheral circuit 140 can obtain the first reference signal u′ from the reference signal pickup point 133, and convert the first reference signal u′ into a second reference signal u″, so that the signal processing circuit 150 can apply the second reference signal u″ to the AFC technology, that is, the signal processing circuit 150 can reduce the feedback component in the first audio signal y based on the second reference signal u″ to obtain the target signal e. Since the feedback component in the target signal e is reduced or eliminated, the acoustic system can avoid or suppress howling, and it also helps to improve the maximum forward gain that the acoustic system can achieve.

[0167] On the other hand, this specification provides a non-transitory storage medium that stores at least one set of executable instructions for performing signal processing. When the executable instructions are executed by a processor, the executable instructions instruct the processor to implement the steps of the signal processing method P100 described in this specification. In some possible implementations, various aspects of this specification can also be implemented in the form of a program product, which includes program code. When the program product is run on an acoustic system, the program code is used to cause the acoustic system to perform the steps of the signal processing method P100 described in this specification. The program product for implementing the above method can use a portable compact disc read-only memory (CD-ROM) to include program code and can be run on the acoustic system. However, the program product of this specification is not limited to this. In this specification, a readable storage medium can be any tangible medium that contains or stores a program that can be used by an instruction execution system or used in combination with it. The program product can use any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media include: an electrical connection having one or more conductors, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The computer-readable storage medium may include a data signal propagated in baseband or as part of a carrier wave, which carries readable program code. Such a propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the foregoing. The computer-readable storage medium may also be any readable medium other than a readable storage medium that can transmit, propagate, or transfer a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the foregoing. Program code for carrying out the operations described herein may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may execute entirely on the acoustic system, partially on the acoustic system, as a stand-alone software package, partially on the acoustic system and partially on a remote computing device, or entirely on the remote computing device.

[0168] The foregoing description of this specification describes specific embodiments. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in an order different from that described in the embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the particular order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0169] In summary, after reading this detailed disclosure, those skilled in the art will appreciate that the foregoing detailed disclosure may be presented by way of example only and may not be limiting. Although not expressly stated herein, those skilled in the art will understand that this specification encompasses various reasonable changes, improvements, and modifications to the embodiments. Such changes, improvements, and modifications are intended to be suggested by this specification and are within the spirit and scope of the exemplary embodiments of this specification.

[0170] Furthermore, certain terms in this specification have been used to describe embodiments of this specification. For example, “one embodiment,” “an embodiment,” and / or “some embodiments” mean that a particular feature, structure, or characteristic described in connection with that embodiment may be included in at least one embodiment of this specification. Therefore, it is emphasized and should be understood that two or more references to “an embodiment,” “one embodiment,” or “an alternative embodiment” in various parts of this specification do not necessarily refer to the same embodiment. Furthermore, particular features, structures, or characteristics may be appropriately combined in one or more embodiments of this specification.

[0171] It should be understood that in the foregoing descriptions of the embodiments of this specification, to facilitate understanding of a feature and to simplify this specification, various features are combined in a single embodiment, figure, or description thereof. However, this does not necessarily mean that these features are combined. When reading this specification, a person skilled in the art may label some of the devices as separate embodiments. In other words, the embodiments of this specification can also be understood as the integration of multiple sub-embodiments. This also applies when each sub-embodiment contains fewer than all the features of a single previously disclosed embodiment.

[0172] Each patent, patent application, patent application publication, and other materials, such as articles, books, specifications, publications, documents, articles, and the like, cited herein, except any historical prosecution documents to which it relates, any equivalent that may be inconsistent or conflicting with this document, or any equivalent historical prosecution documents that may have a limiting effect on the broadest scope of the claims, is hereby incorporated by reference for all purposes now or hereafter connected with this document. In addition, in the event of any inconsistency or conflict between the descriptions, definitions, and / or use of terms associated with any incorporated material and the terminology, descriptions, definitions, and / or use associated with this document, the terminology in this document shall control.

[0173] Finally, it should be understood that the embodiments of the application disclosed herein are illustrative of the principles of the embodiments of this specification. Other modified embodiments are also within the scope of this specification. Therefore, the embodiments disclosed in this specification are merely examples and not limitations. Those skilled in the art can adopt alternative configurations based on the embodiments in this specification to implement the application in this specification. Therefore, the embodiments of this specification are not limited to the embodiments precisely described in the application.

Claims

1. An acoustic system, characterized in that: include: A loudspeaker, which converts the driving signal into a first sound when in operation; A sound pickup component, which converts ambient sound into a first audio signal when in operation, wherein the ambient sound includes the first sound and a second sound from a target sound source; A signal processing circuit connected to the sound pickup assembly; A first peripheral circuit includes an input port and an output port, wherein the output port is connected to the speaker, and a reference signal pickup point exists in the first peripheral circuit; as well as The second peripheral circuit connects the reference signal pickup point and the signal processing circuit, wherein When the first peripheral circuit is running, it obtains a second audio signal through the input port, converts the second audio signal into the driving signal, and sends the driving signal to the speaker through the output port. A second peripheral circuit obtains a first reference signal from the reference signal pickup point during operation and outputs a second reference signal to the signal processing circuit, and When the signal processing circuit is running, based on the second reference signal, it reduces the signal component corresponding to the first sound in the first audio signal to obtain a target signal, and performs a target operation on the target signal.

2. The acoustic system according to claim 1, characterized in that The type of the first reference signal includes at least one of an analog signal, a pulse width modulation PWM signal, a pulse density modulation PDM signal, a pulse code modulation PCM signal, an integrated circuit built-in audio I2S signal, or a time division multiplexing TDM signal.

3. The acoustic system according to claim 1, characterized in that The reference signal pickup point is located at the input port; or The reference signal pickup point is located at the output port.

4. The acoustic system according to claim 1, characterized in that The first peripheral circuit further includes a first processing component, which is connected to the signal processing circuit via the input port, obtains the second audio signal from the signal processing circuit during operation, and performs at least one of a digital-to-analog conversion operation, a modulation operation, and a filtering operation on the second audio signal; and The reference signal pick-off point is located between the first processing component and the output port.

5. The acoustic system according to claim 4, characterized in that The first peripheral circuit further includes a second processing component connected to the first processing component and the output port, wherein: The reference signal pickup point is located between the first processing component and the second processing component, or The reference signal pickup point is located between the second processing component and the output port, or The second processing component includes a plurality of circuit elements, and the reference signal pickup point is located between any two circuit elements of the plurality of circuit elements.

6. The acoustic system according to claim 4, characterized in that The second audio signal is derived from the target signal.

7. The acoustic system according to claim 4, characterized in that The second audio signal comprises a first signal component and a second signal component, wherein The first signal component comes from the target signal, The second signal component comes from a target audio component that is different from the sound pickup component.

8. The acoustic system according to claim 1, characterized in that The input port includes K branch ports, where K is an integer greater than 1; The second audio signal includes K branch audio signals; and The first peripheral circuit obtains the K branch audio signals through the K input ports, and converts the K branch audio signals into the driving signals.

9. The acoustic system according to claim 8, characterized in that The first peripheral circuit further includes a third processing component, which performs at least one of a digital-to-analog conversion operation, a modulation operation, a filtering operation, and a stream mixing operation on the K branch audio signals when in operation; and The reference signal pick-up point is located between the third processing component and the output port.

10. The acoustic system according to claim 8, characterized in that The first peripheral circuit further includes: K branch processing components are connected to the K branch ports respectively, wherein the i-th branch processing component performs at least one of a digital-to-analog conversion operation, a modulation operation, and a filtering operation on the i-th branch audio signal when it is running to obtain an i-th intermediate audio signal, and A first stream mixing component, connected to the K third processing components respectively, and performing a stream mixing operation on the K intermediate audio signals when running; and The reference signal pickup point is located between the first mixing component and the output port.

11. The acoustic system according to claim 8, characterized in that The first peripheral circuit further includes: a second stream mixing component, connected to the K branch ports respectively, and performing a stream mixing operation on the K branch audio signals to obtain a mixed stream audio signal when in operation; and a fourth processing component, connected to the second stream mixing component, and performing at least one of a digital-to-analog conversion operation, a modulation operation, and a filtering operation on the mixed stream audio signal when running; and The reference signal pickup point is located between the second mixing component and the fourth processing component, or the reference signal pickup point is located between the fourth processing component and the output port.

12. The acoustic system according to claim 8, characterized in that The branch audio signals obtained by the first peripheral circuit through the K branch ports all come from the target signal.

13. The acoustic system according to claim 8, characterized in that The K branch ports include a first portion of branch ports and a second portion of branch ports, wherein The branch audio signal obtained by the first peripheral circuit through the first part of the branch ports comes from the target signal, and The branch audio signal obtained by the first peripheral circuit through the second part branch port comes from a target audio component, and the target audio component is different from the pickup component.

14. The acoustic system according to claim 1, characterized in that When the second peripheral circuit is running, it performs at least one of analog-to-digital conversion operation, demodulation operation, filtering operation, and gain operation on the first reference signal to obtain the second reference signal.

15. The acoustic system according to claim 1, characterized in that In order to obtain the target signal, the signal processing circuit: performing an adaptive filtering operation on the second reference signal to obtain a filtered signal; and The target signal is obtained by subtracting the filtered signal from the first audio signal.

16. The acoustic system according to claim 15, characterized in that The signal processing circuit also: Based on at least one of the target signal and the second reference signal, a filtering parameter corresponding to the adaptive filtering operation is updated.

17. The acoustic system according to claim 1, characterized in that When performing the target operation, the signal processing circuit: Performing a gain amplification operation on the target signal to obtain an amplified signal; and The amplified signal is sent to the first peripheral circuit.

18. The acoustic system according to claim 1, characterized in that The pickup assembly includes a sound sensor and a third peripheral circuit, wherein The sound sensor converts the ambient sound into a sound pickup signal when in operation, and The third peripheral circuit converts the picked-up sound signal into the first audio signal when in operation.

19. The acoustic system according to claim 1, characterized in that The signal processing circuit comprises: at least one storage medium storing at least one instruction set for performing signal processing; and at least one processor is communicatively connected to the first peripheral circuit, the second peripheral circuit, the pickup assembly, and the at least one storage medium, wherein when the acoustic system is running, the at least one processor reads the at least one instruction set and executes according to the instructions of the at least one instruction set: Based on the second reference signal, a signal component corresponding to the first sound in the first audio signal is cut to obtain a target signal, and the target operation is performed on the target signal.

20. A signal processing method, characterized in that: Included, through the signal processing circuit in the acoustic system: Obtaining a first audio signal, where the first audio signal is obtained by converting ambient sound by a sound pickup component in the acoustic system, where the ambient sound includes a first sound and a second sound, where the first sound is sound from a speaker in the acoustic system, and the second sound is sound from a target sound source; Obtaining a second reference signal, wherein the second reference signal is obtained by a second peripheral circuit in the acoustic system based on a first reference signal, wherein the first reference signal is obtained by the second peripheral circuit from a reference signal pickup point of a first peripheral circuit in the acoustic system, and the first peripheral circuit is connected to the signal processor and the speaker; Based on the second reference signal, a signal component corresponding to the first sound in the first audio signal is reduced to obtain a target signal; and A target operation is performed on the target signal.

21. The method according to claim 20, characterized in that The type of the first reference signal includes at least one of an analog signal, a pulse width modulation PWM signal, a pulse density modulation PDM signal, a pulse code modulation PCM signal, an integrated circuit built-in audio I2S signal, or a time division multiplexing TDM signal.

22. The method according to claim 20, characterized in that The step of reducing the signal component corresponding to the first sound in the first audio signal based on the second reference signal to obtain a target signal includes: performing an adaptive filtering operation on the second reference signal to obtain a filtered signal; and The target signal is obtained by subtracting the filtered signal from the first audio signal.

23. The method according to claim 22, characterized in that The method further comprises: Based on at least one of the target signal and the second reference signal, a filtering parameter corresponding to the adaptive filtering operation is updated.

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