Acoustic device and signal processing method

Abstract

An acoustic device (100, 200, 300) and a signal processing method. A bone-conduction sound generation assembly (110) of the acoustic device (100, 200, 300) produces a first delay when converting a first driving signal into a bone-conduction acoustic wave, and an air-conduction sound generation assembly (120) produces a second delay when converting a second driving signal into an air-conduction acoustic wave, the absolute value of the difference between the second delay and the first delay being greater than 100 microseconds. A signal processing circuit (130) obtains an audio signal when operating, generates the first driving signal on the basis of a first component of the audio signal and sends same to the bone-conduction sound generation assembly (110), and generates the second driving signal on the basis of a second component of the audio signal and sends same to the air-conduction sound generation assembly (120), wherein the transmission of one of the first driving signal and the second driving signal is delayed relative to the transmission of the other, such that the time difference between the time at which the bone-conduction acoustic wave is generated and the time at which the air-conduction acoustic wave is generated is less than or equal to 100 microseconds at at least some frequencies, thereby avoiding the problem of sound distortion.

Description

Acoustic device and signal processing method

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on October 30, 2023, with application number 2023114373637 and application name “Acoustic Device and Signal Processing Method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] This specification relates to the field of acoustic technology, and in particular to an acoustic device and a signal processing method. Background Art

[0003] Portable acoustic devices (such as headphones) have been widely used in people's daily lives. They can be used in conjunction with electronic devices such as mobile phones and computers to provide users with an auditory feast.

[0004] Based on their working principles, acoustic devices can be divided into air-conduction acoustic devices and bone-conduction acoustic devices. Air-conduction acoustic devices conduct sound waves through air, while bone-conduction acoustic devices conduct sound waves through bones.

[0005] The content of the background technology section is merely information known to the inventor personally, and does not mean that the above information has entered the public domain before the application date of this disclosure, nor does it mean that it can become the prior art of the present disclosure.

[0006] Summary of the Invention

[0007] This specification provides an acoustic device and a signal processing method. For an audio signal to be played, a bone conduction sound component is used to play the first component of the audio signal, and an air conduction sound component is used to play the second component of the audio component, and the problem of tone deviation can be avoided.

[0008] In a first aspect, the present specification provides an acoustic device, comprising: a bone conduction pronunciation component, an air conduction pronunciation component, and a signal processing circuit. The bone conduction pronunciation component generates a first time delay when converting a first drive signal into a bone conduction sound wave; the air conduction pronunciation component generates a second time delay when converting a second drive signal into an air conduction sound wave, and the absolute value of the difference between the second time delay and the first time delay is greater than 100 microseconds; the signal processing circuit is in communication with the bone conduction pronunciation component and the air conduction pronunciation component, and during operation: obtains an audio signal, generates the first drive signal based on the first component of the audio signal and sends it to the bone conduction pronunciation component to drive the bone conduction pronunciation component to convert the first drive signal into the bone conduction sound wave, and generates the second drive signal based on the second component of the audio signal and sends it to the air conduction pronunciation component to drive the air conduction pronunciation component to convert the second drive signal into the air conduction sound wave.

[0009] One of the first drive signal and the second drive signal is sent with a delay relative to the other, so that at at least some frequencies, the bone-conducted sound wave is generated at a first moment and the air-conducted sound wave is generated at a second moment, and the time difference between the first moment and the second moment is less than or equal to 100 microseconds.

[0010] In some embodiments, the at least part of the frequencies includes a target frequency, and the target frequency is a frequency corresponding to an intersection of frequency response curves of the bone-conducted sound wave and the air-conducted sound wave.

[0011] In some embodiments, the first time delay varies with the frequency of the bone conduction sound wave, and the second time delay varies with the frequency of the air conduction sound wave; and the signal processing circuit is further configured to: determine the time delay difference information corresponding to the target frequency, the time delay difference information representing the difference between the first time delay generated by the bone conduction sound component at the target frequency and the second time delay generated by the air conduction sound component at the target frequency, based on the time delay difference information, determine to delay sending the first drive signal relative to the second drive signal, or determine to delay sending the second drive signal relative to the first drive signal, and based on the time delay difference information, determine the delay duration corresponding to the delayed sending.

[0012] In some embodiments, in order to achieve delayed sending of the first drive signal relative to the second drive signal, the signal processing circuit: sends the second drive signal to the air conduction sound component; and caches the first drive signal while sending the second drive signal, and sends the first drive signal to the bone conduction sound component after caching the delay time.

[0013] In some embodiments, in order to achieve delayed sending of the second drive signal relative to the first drive signal, the signal processing circuit: sends the first drive signal to the bone conduction sound component; and caches the second drive signal while sending the first drive signal, and sends the second drive signal to the air conduction sound component after caching the delay time.

[0014] In some embodiments, in order to determine the delay difference information corresponding to the target frequency, the signal processing circuit: obtains a pre-stored correspondence relationship, the correspondence relationship including multiple candidate frequencies and the delay difference information corresponding to each candidate frequency; and queries the correspondence relationship based on the target frequency to obtain the delay difference information corresponding to the target frequency.

[0015] In some embodiments, the delay difference information corresponding to each candidate frequency is obtained by testing in the following manner: generating a single-frequency tone test signal corresponding to the candidate frequency; sending the single-frequency tone test signal to the bone conduction pronunciation component to obtain a first test delay generated when the bone conduction pronunciation component converts the single-frequency tone test signal into a bone conduction test sound wave; sending the single-frequency tone test signal to the air conduction pronunciation component to obtain a second test delay generated when the air conduction pronunciation component converts the single-frequency tone test signal into an air conduction test sound wave; and generating the delay difference information corresponding to the candidate frequency based on the first test delay and the second test delay.

[0016] In some embodiments, the target frequency is 2000 Hz or 500 Hz.

[0017] In some embodiments, the at least part of the frequency includes frequencies in a frequency interval [freq, 2*freq], wherein the freq is a frequency corresponding to an intersection point of voltage curves of the first driving signal and the second driving signal.

[0018] In some embodiments, the first component corresponds to a mid-high frequency component in the audio signal; and the second component corresponds to a mid-low frequency component in the audio signal.

[0019] In some embodiments, to generate the first drive signal, the signal processing circuit: filters the audio signal through a first filter to obtain the first component, the first filter being configured to pass the mid- and high-frequency components in the audio signal, and generates the first drive signal based on the first component; and

[0020] To generate the second drive signal, the signal processing circuit: filters the audio signal through a second filter to obtain the second component, where the second filter is configured to pass the mid- and low-frequency components in the audio signal, and generates the second drive signal based on the second component.

[0021] In some embodiments, the air conduction sound generating assembly comprises at least: an air conduction speaker and a digital power amplifier, wherein the digital power amplifier is connected to an input end of the air conduction speaker; and

[0022] The bone conduction pronunciation component at least includes: a bone conduction speaker and an analog power amplifier, and the analog power amplifier is connected to the input end of the bone conduction speaker.

[0023] In a second aspect, this specification also provides a signal processing method applied to an acoustic device, wherein the acoustic device includes a bone conduction pronunciation component, an air conduction pronunciation component and a signal processing circuit, wherein the bone conduction pronunciation component generates a first time delay when converting a first drive signal into a bone conduction sound wave, and the air conduction pronunciation component generates a second time delay when converting a second drive signal into an air conduction sound wave, and the absolute value of the difference between the second time delay and the first time delay is greater than 100 microseconds.

[0024] The method includes: obtaining an audio signal through the signal processing circuit; generating a first drive signal based on a first component of the audio signal and sending the first drive signal to the bone conduction sound component to drive the bone conduction sound component to convert the first drive signal into the bone conduction sound wave; and generating a second drive signal based on a second component of the audio signal and sending the second drive signal to the air conduction sound component to drive the air conduction sound component to convert the second drive signal into the air conduction sound wave.

[0025] One of the first drive signal and the second drive signal is sent with a delay relative to the other, so that at at least some frequencies, the bone-conducted sound wave is generated at a first moment and the air-conducted sound wave is generated at a second moment, and the time difference between the first moment and the second moment is less than or equal to 100 microseconds.

[0026] In some embodiments, the at least part of the frequencies includes a target frequency, and the target frequency is a frequency corresponding to an intersection of frequency response curves of the bone-conducted sound wave and the air-conducted sound wave.

[0027] In some embodiments, the first time delay varies with the frequency of the bone conduction sound wave, and the second time delay varies with the frequency of the air conduction sound wave; and the method further includes, through the signal processing circuit: determining the time delay difference information corresponding to the target frequency, the time delay difference information representing the difference between the first time delay generated by the bone conduction sound component at the target frequency and the second time delay generated by the air conduction sound component at the target frequency; based on the time delay difference information, determining to delay sending the first drive signal relative to the second drive signal, or determining to delay sending the second drive signal relative to the first drive signal; and based on the time delay difference information, determining the delay duration corresponding to the delayed sending.

[0028] In some embodiments, the delayed sending of the first drive signal relative to the second drive signal includes: sending the second drive signal to the air conduction sound component; and caching the first drive signal while sending the second drive signal, and sending the first drive signal to the bone conduction sound component after caching the delay time.

[0029] In some embodiments, the delayed sending of the second drive signal relative to the first drive signal includes: sending the first drive signal to the bone conduction sound component; and caching the second drive signal while sending the first drive signal, and sending the second drive signal to the air conduction sound component after caching the delay time.

[0030] In some embodiments, determining the delay difference information corresponding to the target frequency includes: obtaining a pre-stored correspondence relationship, the correspondence relationship including multiple candidate frequencies and the delay difference information corresponding to each candidate frequency; and querying the correspondence relationship based on the target frequency to obtain the delay difference information corresponding to the target frequency.

[0031] In some embodiments, the delay difference information corresponding to each candidate frequency is obtained by testing in the following manner: generating a single-frequency tone test signal corresponding to the candidate frequency; sending the single-frequency tone test signal to the bone conduction pronunciation component to obtain a first test delay generated when the bone conduction pronunciation component converts the single-frequency tone test signal into a bone conduction test sound wave; sending the single-frequency tone test signal to the air conduction pronunciation component to obtain a second test delay generated when the air conduction pronunciation component converts the single-frequency tone test signal into an air conduction test sound wave; and generating the delay difference information corresponding to the candidate frequency based on the first test delay and the second test delay.

[0032] In some embodiments, the at least part of the frequency includes frequencies in a frequency interval [freq, 2*freq], wherein the freq is a frequency corresponding to an intersection point of voltage curves of the first driving signal and the second driving signal.

[0033] In some embodiments, the first component corresponds to a mid-high frequency component in the audio signal; and the second component corresponds to a mid-low frequency component in the audio signal.

[0034] In some embodiments, generating the first drive signal based on the first component of the audio signal includes: filtering the audio signal through a first filter to obtain the first component, the first filter being configured to pass the mid- and high-frequency components in the audio signal, and generating the first drive signal based on the first component; and

[0035] Generating the first drive signal based on the first component of the audio signal includes: filtering the audio signal through a second filter to obtain the second component, the second filter being configured to pass the mid- and low-frequency components in the audio signal, and generating the second drive signal based on the second component.

[0036] As can be seen from the above technical solutions, the acoustic device and signal processing method provided in this specification, for the audio signal to be played, uses a bone conduction sound component to play the first component (e.g., mid-high frequency component) of the audio signal, and uses an air conduction sound component to play the second component (e.g., mid-low frequency component) of the audio signal, thereby achieving the mutual fusion of bone conduction and air conduction sound transmission methods. The mid-low frequency air conduction sound waves can be used as a supplement to the mid-high frequency bone conduction sound waves, which can avoid the problem that the bone conduction sound component has poor performance in the low frequency part and brings a strong vibration feeling to the user. In addition, the total output of the acoustic device can cover mid-low frequencies and mid-high frequencies, thereby providing a better sound listening experience. Furthermore, the acoustic device delays the transmission of one of the first drive signal and the second drive signal relative to the other, so that the time difference between the generation moment of the bone conduction sound wave and the generation moment of the air conduction sound wave at at least some frequencies is small (less than or equal to 100 microseconds), so that the target user will not feel the asynchrony between the bone conduction sound wave and the air conduction sound wave, thereby avoiding the problem of pitch deviation.

[0037] Other functions of the acoustic device and signal processing method provided in this specification will be partially listed in the following description. The creative aspects of the acoustic device 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

[0038] 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.

[0039] FIG1 shows an example diagram of a system architecture of an acoustic device provided according to an embodiment of this specification;

[0040] FIG2 is a schematic diagram showing the working time delay of a bone conduction pronunciation component and an air conduction pronunciation component under one situation;

[0041] FIG3 shows a schematic diagram of the working time delay of the bone conduction pronunciation component and the air conduction pronunciation component in another case;

[0042] FIG4 shows a schematic diagram of a system architecture of another acoustic device provided according to an embodiment of this specification;

[0043] FIG5 is a schematic diagram showing frequency response curves of bone-conducted sound waves and air-conducted sound waves output by an acoustic device;

[0044] FIG6A shows a schematic diagram of a 30-cycle single-tone test signal;

[0045] FIG6B shows a recording result of 30 cycles of bone conduction test sound waves generated by the bone conduction pronunciation component;

[0046] FIG6C shows a recording result of 30 cycles of air conduction test sound waves generated by the air conduction pronunciation component;

[0047] FIG7 shows a schematic diagram of delayed sending of the first driving signal;

[0048] FIG8 is a schematic diagram showing delayed sending of the second driving signal;

[0049] FIG9 shows a schematic diagram of a system architecture of another acoustic device provided according to an embodiment of this specification; and

[0050] FIG10 is a schematic flow chart showing a signal processing method according to an embodiment of this specification. DETAILED DESCRIPTION

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] In the embodiments of this specification, prefixes such as "first" and "second" are used solely to distinguish and describe different items belonging to the same category and do not constrain the order or quantity of the items. For example, "first information" and "second information" simply refer to information with different contents or purposes. There is no temporal or priority relationship between the two. The first information may be one or more items, and the second information may also be one or more items.

[0056] In the embodiments of this specification, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the following three situations: A exists alone; A and B exist at the same time; B exists alone; wherein A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can represent: a; b; c; a and b; a and c; b and c; or a, b, and c. wherein a, b, and c can be single or multiple.

[0057] The acoustic device provided in this specification is a wearable acoustic device. The acoustic device can be worn on the head of the target user and output sound to the target user. For example, the acoustic device can be worn near the two ears of the target user, in which case the acoustic device can also be called headphones. It should be noted that the acoustic device provided in this specification can be designed in a variety of forms, such as: earmuff type, glasses type, ear hook type, ear hook + back hook type, ear clip type (ear clip type), etc. This specification does not limit the specific form of the acoustic device.

[0058] The acoustic device provided in this specification may be a headset that combines bone conduction and air conduction. That is, the acoustic device can transmit sound to the human ear through both bone conduction (e.g., skull bone conduction) and air conduction. The acoustic device provided in this specification is described in detail below with reference to the accompanying drawings.

[0059] Fig. 1 shows an exemplary system architecture diagram of an acoustic device 100 according to an embodiment of this specification. As shown in Fig. 1 , the acoustic device 100 may include a bone conduction sound component 110, an air conduction sound component 120, a signal processing circuit 130, and an audio input component 140.

[0060] Both the bone conduction sound component 110 and the air conduction sound component 120 are communicatively connected to the signal processing circuit 130. The bone conduction sound component 110 can receive electrical signals carrying audio information from the signal processing circuit 130 and convert them into bone-conducted sound waves. Bone-conducted sound waves refer to sound waves transmitted from mechanical vibrations through the bones to the ear, and can also be referred to as bone-conducted sound. The air conduction sound component 120 can receive electrical signals carrying audio information from the signal processing circuit 130 and convert them into air-conducted sound waves. Air-conducted sound waves refer to sound waves transmitted from mechanical vibrations through the air to the ear, and can also be referred to as air-conducted sound.

[0061] For the sake of distinction, this specification refers to the electrical signal received by the bone conduction sound component 110 from the signal processing circuit 130 as the first driving signal, and the electrical signal received by the air conduction sound component 120 from the signal processing circuit 130 as the second driving signal.

[0062] 1 , the bone conduction sound generating assembly 110 may include a bone conduction speaker 112. The bone conduction speaker 112 is a device for converting electrical signals into bone-conducted sound waves, and may also be referred to as an electroacoustic transducer or a bone conduction speaker.

[0063] In addition to the bone conduction speaker 112, the bone conduction sound component 110 may also include a first peripheral circuit (e.g., a first power amplifier 111). The first peripheral circuit may be located at the input end of the bone conduction speaker 112. For example, in FIG1 , the first peripheral circuit may be connected between the signal processing circuit 130 and the bone conduction speaker 112. The first peripheral circuit may receive a first drive signal from the signal processing circuit 130 and perform some processing on the first drive signal so that the processed electrical signal is suitable for playback by the bone conduction speaker 112 and has a better listening effect. In some embodiments, the first peripheral circuit may include one or more circuit elements, such as a power amplifier element, a digital-to-analog / analog-to-digital conversion element, a filter element, a capacitor, an inductor, and the like. Those skilled in the art will appreciate that, for ease of illustration, FIG1 only shows the power amplifier element in the first peripheral circuit and labels it as the first power amplifier 111.

[0064] 1 , the air conduction sound generating assembly 120 may include an air conduction speaker 122. The air conduction speaker 122 is a device for converting electrical signals into air conduction sound waves, and may also be referred to as an electroacoustic transducer or an air conduction speaker.

[0065] In addition to the air conduction speaker 122, the air conduction sound generating component 120 may also include a second peripheral circuit (e.g., a second power amplifier 121). The second peripheral circuit may be located at the input end of the air conduction speaker 122. For example, in FIG1 , the second peripheral circuit may be connected between the signal processing circuit 130 and the air conduction speaker 122. The second peripheral circuit may receive a second drive signal from the signal processing circuit 130, and perform some processing on the second drive signal so that the processed electrical signal is suitable for playback by the air conduction speaker 122 and has a better listening effect. In some embodiments, the second peripheral circuit may include one or more circuit elements, such as a power amplifier element, a digital-to-analog / analog-to-digital conversion element, a filter element, a capacitor, an inductor, and the like. Those skilled in the art will appreciate that, for the sake of convenience, FIG1 only shows the power amplifier element in the second peripheral circuit, and it is marked as the second power amplifier 121.

[0066] The signal processing circuit 130 is a circuit with certain signal processing capabilities. Referring to Figure 1, the signal processing circuit 130 can be communicatively connected to the audio input component 140. The signal processing circuit 130 can obtain the audio signal to be played from the audio input component 140. In some embodiments, the audio input component 140 can be a component with a storage function, and the audio signal can be a signal pre-stored in the audio input component 140. In this case, the signal processing circuit 130 can obtain the audio signal from the audio input component 140. In some embodiments, the audio input component 140 can correspond to the audio interface of the acoustic device 100. The acoustic device 100 can be communicatively connected to a control device (such as a mobile phone, tablet, computer, etc.) through the audio interface and receive the audio signal from the control device. In some embodiments, the audio input component 140 can correspond to the sound pickup component of the acoustic device 100. The acoustic device 100 picks up ambient sound through the sound pickup component and converts it into the audio signal, and the signal processing circuit 130 can obtain the audio signal from the sound pickup component.

[0067] The signal processing circuit 130 is in communication with the bone conduction sound component 110 and the air conduction sound component 120. After obtaining the audio signal to be played, the signal processing circuit 130 can perform a frequency division operation on the audio signal to generate a first drive signal and a second drive signal. Furthermore, the signal processing circuit 130 can send the first drive signal to the bone conduction sound component 110 and the second drive signal to the air conduction sound component 120.

[0068] When performing the frequency division operation, the signal processing circuit 130 may generate the first drive signal based on the first component in the audio signal, and generate the second drive signal based on the second component in the audio signal. The first component and the second component may correspond to different frequency components in the audio signal, respectively. For example, in some embodiments, the first component may correspond to a mid-high frequency component in the audio signal, and the second component may correspond to a mid-low frequency component in the audio signal.

[0069] In this specification, different frequency ranges can be determined according to actual needs. For example, low frequency can refer to the frequency band of approximately 20Hz to 150Hz, medium frequency can refer to the frequency band of approximately 150Hz to 5KHz, high frequency can refer to the frequency band of approximately 5KHz to 20KHz, medium-low frequency can refer to the frequency band of approximately 150Hz to 500Hz, and medium-high frequency can refer to the frequency band of 500Hz to 5KHz. For another example, low frequency can refer to the frequency band of approximately 20-300Hz, medium frequency range can refer to the frequency band of approximately 300Hz-3kHz, high frequency range can refer to the frequency band of 3kHz-20kHz, medium-low frequency can refer to the frequency band of 100Hz-1kHz, and medium-high frequency can refer to the frequency band of 1kHz-10kHz. Those skilled in the art will understand that the distinction between the above frequency bands is only given as an example. The definition of the above frequency bands can change with different industries, different application scenarios and different classification standards. For example, in some other application scenarios, low frequency refers to the frequency band of approximately 20Hz to 80Hz, mid-low frequency may refer to the frequency band of approximately 80Hz-160Hz, mid-frequency may refer to the frequency band of approximately 160Hz to 1280Hz, mid-high frequency may refer to the frequency band of approximately 1280Hz-2560Hz, and high frequency may refer to the frequency band of approximately 2560Hz to 20kHz. It should be noted that in some scenarios, there may be overlapping frequencies between different frequency ranges.

[0070] In some embodiments, the signal processing circuit 130 can generate the first drive signal in the following manner. The signal processing circuit 130 filters the audio signal through a first filter to obtain a first component. The first filter is configured to allow the mid- and high-frequency components in the audio signal to pass through, and therefore, the first filter can also be called a high-pass filter. It should be noted that this specification does not limit the type of the first filter. For example, in some embodiments, the first filter can adopt a 4th-order digital filter. After obtaining the first component, the signal processing circuit 130 can generate the first drive signal based on the first component. For example, the first drive signal can be obtained after performing a target operation on the first component. In some embodiments, the target operation may include but is not limited to one or more of a filtering operation and a gain operation. Those skilled in the art will understand that the first drive signal generated in the above manner corresponds to the mid- and high-frequency signal components in the audio signal.

[0071] In some embodiments, the signal processing circuit 130 can generate the second drive signal in the following manner. The signal processing circuit 130 filters the audio signal through a second filter to obtain a second component. The second filter is configured to allow the mid- and low-frequency components in the audio signal to pass through. Therefore, the second filter can also be called a low-pass filter. It should be noted that this specification does not limit the type of the second filter. For example, in some embodiments, the second filter can adopt a 4th-order digital filter. After obtaining the second component, the signal processing circuit 130 can generate the second drive signal based on the second component. For example, a target operation can be performed on the second component to obtain the second drive signal. In some embodiments, the target operation can include but is not limited to one or more of a filtering operation and a gain operation. Those skilled in the art will understand that the second drive signal generated in the above manner corresponds to the mid- and low-frequency signal components in the audio signal.

[0072] The acoustic device 100 provided in this specification converts the mid- and high-frequency components of the audio signal into bone-conducted sound waves through the bone conduction sound component 110, and converts the mid- and low-frequency components of the audio signal into air-conducted sound waves through the air conduction sound component 120. This achieves the integration of bone conduction and air conduction sound transmission methods. The mid- and low-frequency air-conducted sound waves can be used to supplement the mid- and high-frequency bone-conducted sound waves, thus avoiding the problem of poor low-frequency performance of the bone conduction sound component 110, which can cause strong vibration sensations to the user. The total output of the acoustic device 100 can cover both mid- and low-frequency frequencies, thereby providing a better listening experience.

[0073] Based on the system architecture of the acoustic device 100 shown in Figure 1, both the bone conduction sound component 110 and the air conduction sound component 120 have a certain time delay during operation. For the convenience of description, in this specification, the "time delay generated by the bone conduction sound component 110 when converting the first drive signal into a bone conduction sound wave" is referred to as the first time delay, and the "time delay generated by the air conduction sound component 120 when converting the second drive signal into an air conduction sound wave" is referred to as the second time delay. The first time delay may refer to: the time interval between the bone conduction sound component 110 receiving the first drive signal and outputting the bone conduction sound wave. The second time delay may refer to: the time interval between the air conduction sound component 120 receiving the second drive signal and outputting the air conduction sound wave.

[0074] Those skilled in the art will appreciate that the aforementioned first time delay is related to the hardware solution adopted by the bone conduction sound component 110 (i.e., the components used in the bone conduction sound component 110). When the bone conduction sound component 110 adopts different hardware solutions, the first time delay generated during the operation of the bone conduction sound component 110 will be different. Similarly, the aforementioned second time delay is related to the hardware solution adopted by the air conduction sound component 120 (i.e., the components used in the air conduction sound component 120). When the air conduction sound component 120 adopts different hardware solutions, the second time delay generated during the operation of the air conduction sound component 120 will also be different.

[0075] In actual applications, the bone conduction sound component 110 and the air conduction sound component 120 typically employ different hardware solutions to meet the needs of different scenarios. In some embodiments, when the acoustic device 100 is used in a scenario with high power consumption requirements, in order to reduce the overall power consumption of the acoustic device 100, the following hardware solution is typically adopted: the first power amplifier 111 in the bone conduction sound component 110 is an analog power amplifier, while the second power amplifier 121 in the air conduction sound component 120 is a digital power amplifier.

[0076] When the first power amplifier 111 is an analog power amplifier and the second power amplifier 121 is a digital power amplifier, the operating speeds of the analog and digital power amplifiers differ. Therefore, the first time delay generated by the bone conduction sound component 110 differs from the second time delay generated by the air conduction sound component 120. Furthermore, if the first and second time delays differ, if the bone conduction sound component 110 and the air conduction sound component 120 receive a drive signal simultaneously, the bone conduction sound waves and the air conduction sound waves will not be emitted synchronously. This is illustrated below with reference to Figures 2 and 3.

[0077] Figure 2 shows a schematic diagram of the operating delays of the bone conduction sound component 110 and the air conduction sound component 120 under one scenario. As shown in Figure 2, assume that the first delay generated by the bone conduction sound component 110 during operation is less than the second delay generated by the air conduction sound component 120 during operation. In this scenario, if the bone conduction sound component 110 and the air conduction sound component 120 receive drive signals simultaneously, that is, the bone conduction sound component 110 receives the first drive signal at time T1, and the air conduction sound component 120 receives the second drive signal at time T1, because the first delay generated by the bone conduction sound component 110 during operation is less than the second delay generated by the air conduction sound component 120 during operation, the bone conduction sound component 110 will emit sound waves before the air conduction sound component 120. That is, the bone conduction sound component 110 emits bone-conducted sound waves at time T2, while the air conduction sound component 120 emits air-conducted sound waves at time T3, with time T2 being earlier than time T3.

[0078] Figure 3 shows a schematic diagram of the operating delays of the bone conduction sound component 110 and the air conduction sound component 120 under another scenario. As shown in Figure 3 , assume that the first delay generated by the bone conduction sound component 110 is greater than the second delay generated by the air conduction sound component 120. In this scenario, if the bone conduction sound component 110 and the air conduction sound component 120 receive drive signals simultaneously, that is, the bone conduction sound component 110 receives the first drive signal at time T1, and the air conduction sound component 120 receives the second drive signal at time T1, because the first delay generated by the bone conduction sound component 110 is greater than the second delay generated by the air conduction sound component 120, the air conduction sound component 120 will emit sound waves before the bone conduction sound component 110. That is, the air conduction sound component 120 emits air conduction sound waves at time T4, while the bone conduction sound component 110 emits bone conduction sound waves at time T5, with time T4 being earlier than time T5.

[0079] As can be seen from Figures 2 and 3, when the first time delay generated when the bone conduction sound component 110 is working is different from the second time delay generated when the air conduction sound component 120 is working (for example, the first time delay is less than the second time delay, or the first time delay is greater than the second time delay), the acoustic device 100 cannot synchronously emit bone conduction sound waves and air conduction sound waves. Assuming that the acoustic device 100 generates bone conduction sound waves at the first moment and generates air conduction sound waves at the second moment, there is a time difference between the first moment and the second moment. Furthermore, when the above-mentioned time difference is large (for example, greater than 100 microseconds), the target user can more clearly feel the asynchrony between the bone conduction sound waves and the air conduction sound waves, resulting in a sound deviation problem. In this specification, sound deviation refers to a user's sense of hearing, that is, the position of the sound perceived by the user is biased to the left or right. The sound deviation problem will reduce the user's experience of using the acoustic device 100.

[0080] To this end, this specification also provides an acoustic device 200. After generating a first drive signal and a second drive signal based on an audio signal, the acoustic device 200 delays the transmission of at least one of the first drive signal and the second drive signal, so that at at least some frequencies, the time difference between the generation time of the bone-conducted sound wave and the generation time of the air-conducted sound wave is small (e.g., less than or equal to 100 microseconds), thereby avoiding the problem of sound deviation. The acoustic device 200 provided in this specification is described in detail below with reference to FIG4.

[0081] Figure 4 shows a schematic diagram of the system architecture of another acoustic device 200 provided according to an embodiment of this specification. Comparing Figure 4 with Figure 1 shows that the system architecture of acoustic device 200 is similar to that of acoustic device 100. The difference between the two is that after the signal processing circuit 130 generates the first drive signal and the second drive signal by performing a frequency division operation, it can perform a "delayed transmission operation" on at least one of the first drive signal and the second drive signal, so that one of the first drive signal and the second drive signal is delayed relative to the other. For example, the first drive signal is delayed relative to the second drive signal, or the second drive signal is delayed relative to the first drive signal.

[0082] It should be noted that the “delayed sending operation” in FIG4 is marked with a dotted box, which means that the signal processing circuit 130 can selectively perform the “delayed sending operation”. For example, the signal processing circuit 130 can perform the “delayed sending operation” on the first drive signal, but not perform the “delayed sending operation” on the second drive signal, so that the first drive signal is delayed in sending relative to the second drive signal. For another example, the signal processing circuit 130 can perform the “delayed sending operation” on the second drive signal, but not perform the “delayed sending operation” on the first drive signal, so that the second drive signal is delayed in sending relative to the first drive signal. For another example, the signal processing circuit 130 can perform the “delayed sending operation” on both the first drive signal and the second drive signal, but the delay durations of the two are different, so that one of them is delayed in sending relative to the other.

[0083] The signal processing circuit 130 performs a "delayed transmission operation" on at least one of the first and second drive signals to delay transmission of one relative to the other. This reduces the time difference between the bone-conducted sound wave and the air-conducted sound wave at at least some frequencies. For example, the time difference can be less than or equal to 100 microseconds. Consequently, the target user does not perceive asynchrony between the bone-conducted and air-conducted sound waves, thus avoiding sound distortion.

[0084] The sound received by the target user is a composite of bone-conducted and air-conducted sound waves. Figure 5 shows a schematic diagram of the frequency response curves of the bone-conducted and air-conducted sound waves output by the acoustic device. As shown in Figure 5, Curve 1 is the frequency response curve for the air-conducted sound wave, and Curve 2 is the frequency response curve for the bone-conducted sound wave. Based on Curves 1 and 2, it can be seen that in the low-frequency range (for example, the frequency range below F1), the intensity of the air-conducted sound waves received by the target user is much greater than that of the bone-conducted sound waves. In other words, the target user's hearing experience is primarily determined by the air-conducted sound waves. Therefore, in the low-frequency range, even if there is a time difference between the generation time of the bone-conducted sound wave and the generation time of the air-conducted sound wave, the target user generally does not perceive a noticeable sound offset. In the high-frequency range (for example, the frequency range above F2), the intensity of the bone-conducted sound waves received by the target user is much greater than that of the air-conducted sound waves. In other words, the target user's hearing experience is primarily determined by the bone-conducted sound waves. Therefore, in the high-frequency range, even if there is a time difference between the generation time of the bone-conducted sound wave and the generation time of the air-conducted sound wave, the target user generally does not perceive a noticeable sound offset. In the mid-frequency band (for example, the frequency range between F1 and F2), the intensity of the bone-conducted sound wave is not much different from that of the air-conducted sound wave. Therefore, when there is a time difference between the generation time of the bone-conducted sound wave and the generation time of the air-conducted sound wave, especially when the time difference is greater than 100 microseconds, the target user will feel a significant sound deviation.

[0085] From the above analysis, it can be seen that the problem of sound deviation can be effectively avoided when the acoustic device meets the following condition A. Condition A: At frequencies corresponding to the intermediate frequency band, the time difference between the generation moment of the bone-conducted sound wave and the generation moment of the air-conducted sound wave is small (less than or equal to 100 microseconds). Therefore, in some embodiments, the at least some frequencies may include frequencies in the intermediate frequency band. In other words, the signal processing circuit 130 can perform a "delayed transmission operation" on at least one of the first drive signal and the second drive signal so that the time difference between the generation moment of the bone-conducted sound wave and the generation moment of the air-conducted sound wave at frequencies in the intermediate frequency band is small (less than or equal to 100 microseconds).

[0086] In some embodiments, at least some of the frequencies may include frequencies in a frequency interval [freq, 2*freq], where freq is the frequency corresponding to the intersection of the voltage curves of the first drive signal and the second drive signal. For example, assuming that the frequency corresponding to the intersection between the voltage curve of the first drive signal and the voltage curve of the second drive signal is 1200 Hz, the signal processing circuit performs a "delayed transmission operation" on at least one of the first drive signal and the second drive signal, such that at least some frequencies in the frequency interval [1200 Hz, 2400 Hz] have a small time difference (less than or equal to 100 microseconds) between the generation time of the bone conduction sound wave and the generation time of the air conduction sound wave. The voltage curve of the first drive signal and the voltage curve of the second drive signal can both be obtained by detecting the output signal of a circuit board (the circuit board corresponding to the signal processing circuit 130).

[0087] Continuing with Figure 5 , the intersection of Curve 1 and Curve 2 is denoted as Q, and the frequency corresponding to intersection Q is called target frequency F0. Since target frequency F0 corresponds to the intersection of the bone-conducted sound wave and the air-conducted sound wave, the intensity of the air-conducted sound wave is greater than that of the bone-conducted sound wave before target frequency F0, and greater than that of the air-conducted sound wave after target frequency F0. Therefore, target frequency F0 can also be called the crossover frequency between the bone-conducted sound wave and the air-conducted sound wave (i.e., the frequency corresponding to the crossover point).

[0088] It should be noted that the above-mentioned target frequency F0 refers to the frequency corresponding to the acoustic crossover point between the bone conduction sound wave and the air conduction sound wave, that is, the crossover point in the hearing perception of the target user. In actual applications, due to the low energy conversion efficiency of the bone conduction speaker 112, the current intensity of the driving signal of the bone conduction speaker 112 is usually increased, thereby increasing the volume output by the bone conduction speaker 112. This will cause the frequency response curve of the bone conduction sound wave obtained in the actual test to shift upward as a whole. The frequency response curve after the upward shift is shown in curve 3 in Figure 5 (represented by a dotted line). As can be seen from Figure 5, the intersection point of the frequency response curve of the bone conduction sound wave obtained in the actual test and the frequency response curve of the air conduction sound wave will shift to the left to point P. When the target frequency is 2000Hz, the frequency corresponding to the intersection point P obtained by actual measurement is approximately 1200Hz. In some embodiments, considering that the frequency response curve of bone-conducted sound waves is not very convenient to test, the electrical signal corresponding to the bone-conducted sound waves (i.e., curve 3 in FIG5 ) can be used to replace the frequency response curve of the bone-conducted sound waves. In this case, the intersection point of the frequency response curves of the bone-conducted sound waves and the air-conducted sound waves is P.

[0089] Because the target frequency F0 corresponds to the intersection point Q of the frequency curves of the bone-conducted and air-conducted sound waves, the intensities of the bone-conducted and air-conducted sound waves at the target frequency F0 are equal. This means that they have a comparable impact on the user's hearing experience. Therefore, the time delay between the bone-conducted and air-conducted sound waves at the target frequency F0 has a significant impact on sound distortion. In other words, sound distortion in acoustic devices is largely caused by the asynchrony between the bone-conducted and air-conducted sound waves at the target frequency F0.

[0090] From the above analysis, it can be seen that the acoustic device can more effectively avoid the problem of sound deviation when it meets the following condition B. Condition B: At the target frequency F0, the time difference between the generation moment of the bone-conducted sound wave and the generation moment of the air-conducted sound wave is small (less than or equal to 100 microseconds). Therefore, in some embodiments, the at least some frequencies may include the target frequency F0. In other words, the signal processing circuit 130 can perform a "delayed transmission operation" on at least one of the first drive signal and the second drive signal, so that the time difference between the generation moment of the bone-conducted sound wave and the generation moment of the air-conducted sound wave at the target frequency F0 is small (less than or equal to 100 microseconds).

[0091] In some embodiments, the target frequency F0 can be 500 Hz. In this case, air-conducted sound waves primarily cover the frequency range below 500 Hz, while bone-conducted sound waves primarily cover the frequency range above 500 Hz. Because bone-conducted sound waves barely vibrate in the human body above 500 Hz, when the target frequency is 500 Hz, the user barely feels the vibration of the acoustic device, improving the wearing experience.

[0092] In some embodiments, the target frequency F0 can be 2000Hz. In this case, the air-conducted sound waves mainly cover the frequency range below 2000Hz, and the bone-conducted sound waves mainly cover the frequency range above 2000Hz. The bone-conduction sound component 110 has a lower sensitivity than the air-conduction sound component 120. Therefore, the power consumption generated by the bone-conduction sound component 110 is higher, and the power consumption generated by the air-conduction sound component 120 is lower. Increasing the target frequency F0 from 500Hz to 2000Hz increases the frequency range covered by the air-conducted sound waves and reduces the frequency range covered by the bone-conducted sound waves while avoiding a sense of vibration to the user. This is equivalent to making full use of the advantage of the lower power consumption of the air-conduction sound component 120, and therefore, can reduce the overall power consumption of the acoustic device.

[0093] The following describes in detail how the signal processing circuit 130 determines which drive signal to perform the delayed transmission operation on and how to perform the delayed transmission operation. The test data described below is illustrated by taking the first power amplifier 111 as an analog power amplifier and the second power amplifier 121 as a digital power amplifier as an example.

[0094] The inventors found in actual research that the first time delay generated by the bone conduction sound component 110 during operation is not fixed, but varies with the frequency. For example, the first time delay generated at the frequency f1 when the bone conduction sound component 110 is The first delay generated at frequency f2 is Similarly, the second time delay generated by the air conduction sound component 120 during operation is not fixed, but varies with the frequency. For example, the second time delay generated at the frequency f1 when the air conduction sound component 120 is working is The second delay generated at frequency f2 is

[0095] Furthermore, the inventors have found in actual research that the relationship between the first delay and the second delay is not fixed, but varies with the frequency. For example, for frequency f1, the first delay generated when the bone conduction sound component 110 works is The second time delay generated when the air conduction pronunciation component 120 works is For frequency f2, the first time delay generated when the bone conduction pronunciation component 110 works is The second time delay generated when the air conduction pronunciation component 120 works is That is, at some frequencies, the first delay generated by the bone conduction sound component 110 is greater than the second delay generated by the air conduction sound component 120, while at other frequencies, the first delay generated by the bone conduction sound component 110 is less than the second delay generated by the air conduction sound component 120.

[0096] Based on the above analysis, in some embodiments, the signal processing circuit 130 may determine which driving signal to delay sending and determine the delay duration corresponding to the delayed sending in the following manner.

[0097] (1) Determine the time delay difference information corresponding to the target frequency F0, wherein the time delay difference information represents the difference between a first time delay generated by the bone conduction sound component 110 at the target frequency F0 and a second time delay generated by the air conduction sound component 120 at the target frequency F0.

[0098] According to the above analysis, at different frequencies, the difference between the first time delay generated by the bone conduction sound component 110 and the second time delay generated by the air conduction sound component 120 may have different manifestations. For example, at frequency f1, the first time delay generated by the bone conduction sound component 110 may be greater than the second time delay generated by the air conduction sound component 120, while at frequency f2, the first time delay generated by the bone conduction sound component 110 may be less than the second time delay generated by the air conduction sound component 120. Therefore, before the acoustic device 200 leaves the factory, the bone conduction sound component 110 and the air conduction sound component 120 can be tested for multiple candidate frequencies to obtain the time delay difference information corresponding to each candidate frequency. Among them, the candidate frequency refers to the frequency that may serve as the crossover point between the bone conduction sound wave and the air conduction sound wave. For example, the multiple candidate frequencies may include 2000Hz and 500Hz.

[0099] Among them, the testing method for each candidate frequency is as follows: generate a single-frequency tone test signal corresponding to the candidate frequency; send the single-frequency tone test signal to the bone conduction pronunciation component 110 to obtain a first test delay generated when the bone conduction pronunciation component 110 converts the single-frequency tone test signal into a bone conduction test sound wave; send the single-frequency tone test signal to the air conduction pronunciation component 120 to obtain a second test delay generated when the air conduction pronunciation component 120 converts the single-frequency tone test signal into an air conduction test sound wave; based on the first test delay and the second test delay, generate delay difference information corresponding to the candidate frequency.

[0100] For ease of understanding, the following describes the delay difference information testing process by taking the candidate frequency 2000 Hz as an example with reference to FIG. 6A to FIG. 6C .

[0101] First, generate a k-cycle 2000Hz single-frequency tone test signal. The value of k is not limited, but it is necessary to ensure that the k-cycle single-frequency tone test signal contains a certain number of cycles of amplitude-stable signals. For example, the value of k can be 30, in which case a 30-cycle single-frequency tone signal typically contains 12 cycles of amplitude-stable signals. Figure 6A shows a schematic diagram of a 30-cycle single-frequency tone test signal.

[0102] The above-mentioned 30-cycle single-frequency tone test signal is sent to the bone conduction pronunciation component 110 and the air conduction pronunciation component 120 respectively. The bone conduction pronunciation component 110 converts the above-mentioned 30-cycle single-frequency tone test signal into 30-cycle bone conduction test sound waves, and the air conduction pronunciation component 120 converts the above-mentioned 30-cycle single-frequency tone test signal into 30-cycle air conduction test sound waves. During the above-mentioned test process, the working process of the bone conduction pronunciation component 110 is recorded using Audition software, so as to obtain the 30-cycle bone conduction test sound waves generated by the bone conduction pronunciation component 110, and obtain the generation time corresponding to each cycle of the bone conduction test sound waves. Similarly, during the above-mentioned test process, the working process of the air conduction pronunciation component 120 is recorded using Audition software, so as to obtain the 30-cycle air conduction test sound waves generated by the air conduction pronunciation component 120, and obtain the generation time corresponding to each cycle of the air conduction test sound waves. Figure 6B shows the recording result of 30 cycles of bone conduction test sound waves generated by the bone conduction sound component 110. Figure 6B shows the generation time corresponding to each cycle of the bone conduction test sound waves. Figure 6C shows the recording result of 30 cycles of air conduction test sound waves generated by the air conduction sound component 120. Figure 6C shows the generation time corresponding to each cycle of the air conduction test sound waves.

[0103] After recording Figures 6B and 6C, the time delay difference information can be obtained by comparing the generation moments of the bone conduction test sound waves and the air conduction test sound waves of the same period. In order to improve the accuracy of the time delay difference information, a period with stable amplitude can be selected for comparison. For example, one or more periods can be selected for comparison from the 9th to the 20th period. In conjunction with Figures 6B and 6C, taking the selection of the 9th period for comparison as an example, it can be concluded through comparison that the time delay difference information corresponding to the candidate frequency 2000Hz is: the first time delay generated by the bone conduction pronunciation component 110 at a frequency of 2000Hz is 0.85 milliseconds greater than the second time delay generated by the air conduction pronunciation component 120 at a frequency of 2000Hz.

[0104] Those skilled in the art will appreciate that the above description is based on an example of the test process for the delay difference information using the candidate frequency 2000 Hz, and similar test methods can be used for other candidate frequencies, which will not be described one by one in this specification.

[0105] After the delay difference information corresponding to each candidate frequency is obtained through testing, the corresponding relationship can be pre-stored in the acoustic device 200. The above-mentioned corresponding relationship may include: multiple candidate frequencies and the delay difference information corresponding to each candidate frequency. For example, taking two candidate frequencies of 2000Hz and 500Hz as an example, assuming that the delay difference information corresponding to the candidate frequency 2000Hz is: the first delay generated by the bone conduction sound component 110 at a frequency of 2000Hz is 0.85 milliseconds greater than the second delay generated by the air conduction sound component 120 at a frequency of 2000Hz; the delay difference information corresponding to the candidate frequency 500Hz is: the first delay generated by the bone conduction sound component 110 at a frequency of 500Hz is 0.20 milliseconds less than the second delay generated by the air conduction sound component 120 at a frequency of 500Hz. Then, the corresponding relationship shown in Table 1 below can be stored in the acoustic device 200.

[0106] Table 1 Candidate frequencies and their corresponding test results

[0107] In this way, when the signal processing circuit 130 needs to determine the delay difference information corresponding to the target frequency F0, it can obtain the above-mentioned pre-stored corresponding relationship, and query the corresponding relationship based on the target frequency F0 to obtain the delay difference information corresponding to the target frequency F0. For example, assuming that the target frequency F0 is 500Hz, the signal processing circuit 130 queries Table 1 based on the target frequency 500Hz to obtain the delay difference information corresponding to the target frequency 500Hz. For another example, assuming that the target frequency F0 is 2000Hz, the signal processing circuit 130 queries Table 1 based on the target frequency 2000Hz to obtain the delay difference information corresponding to the target frequency 2000Hz. The above method pre-measures the delay difference information corresponding to multiple candidate frequencies and stores the measurement results. On the one hand, it can quickly obtain the delay difference information corresponding to the target frequency based on the pre-stored measurement results, and on the other hand, it can also ensure the accuracy of the obtained delay difference information.

[0108] (2) Based on the delay difference information, determining to delay sending the first drive signal relative to the second drive signal, or determining to delay sending the second drive signal relative to the first drive signal.

[0109] In other words, the signal processing circuit 130 can determine which drive signal to delay based on the delay difference information. Specifically, if the delay difference information indicates that the first delay generated by the bone conduction sound component 110 at the target frequency F0 is greater than the second delay generated by the air conduction sound component 120, the signal processing circuit 130 determines to delay the transmission of the second drive signal relative to the first drive signal. If the delay difference information indicates that the first delay generated by the bone conduction sound component 110 at the target frequency F0 is less than the second delay generated by the air conduction sound component 120, the signal processing circuit 130 determines to delay the transmission of the first drive signal relative to the second drive signal.

[0110] (3) Based on the delay difference information, determine the delay duration corresponding to the delayed transmission.

[0111] Specifically, after determining which driving signal is to be delayed in sending, the signal processing circuit 130 may further determine how long to delay sending the driving signal based on the delay difference information.

[0112] Table 1 is used as an example.

[0113] If the target frequency F0 is 2000 Hz, based on Table 1, since the first delay generated by the bone conduction sound component 110 at a frequency of 2000 Hz is 0.85 milliseconds greater than the second delay generated by the air conduction sound component 120 at a frequency of 2000 Hz, the signal processing circuit 130 can determine that the second drive signal is delayed relative to the first drive signal, and determine that the delay duration corresponding to the delayed transmission is 0.85 milliseconds.

[0114] If the target frequency F0 is 500 Hz, based on Table 1, since the first delay generated by the bone conduction sound component 110 at a frequency of 500 Hz is 0.20 milliseconds smaller than the second delay generated by the air conduction sound component 120 at a frequency of 500 Hz, the signal processing circuit 130 can determine that the first drive signal is delayed relative to the second drive signal, and determine that the delay duration corresponding to the delayed transmission is 0.20 milliseconds.

[0115] In some embodiments, after pre-testing and obtaining the time delay difference information corresponding to multiple candidate frequencies, the delay scheme corresponding to each candidate frequency (i.e., which drive signal is delayed and how long the delay is) can be determined based on the time delay difference information corresponding to each candidate frequency. For example, for the candidate frequency of 2000 Hz, it can be determined that the second drive signal needs to be delayed relative to the first drive signal, and the delay time corresponding to the delayed transmission is 0.85 milliseconds. For the candidate frequency of 500 Hz, it can be determined that the first drive signal needs to be delayed relative to the second drive signal, and the delay time corresponding to the delayed transmission is 0.2 milliseconds. Thus, the delay schemes corresponding to the multiple candidate frequencies are obtained, as shown in Table 2.

[0116] Table 2 Candidate frequencies and their corresponding delay schemes

[0117] Furthermore, the delay scheme shown in Table 2 can be pre-stored in the acoustic device 200. In this way, the signal processing circuit 130 can query Table 2 based on the target frequency F0 to obtain the delay scheme corresponding to the target frequency F0, thereby determining which drive signal to delay and the duration of the delayed transmission. For example, assuming that the target frequency F0 is 2000Hz, by querying Table 2, it can be determined that the second drive signal is delayed and the corresponding delay duration is 0.85 milliseconds. For another example, assuming that the target frequency is 500Hz, by querying Table 2, it can be determined that the first drive signal is delayed and the corresponding delay duration is 0.2 milliseconds.

[0118] 7 and 8 , an example is given below to illustrate how the signal processing circuit 130 implements delayed transmission.

[0119] Figure 7 shows a schematic diagram of delaying the transmission of the first drive signal. Assuming a target frequency of 500 Hz, the signal processing circuit 130, using the method described above, can determine that the first drive signal needs to be delayed by 0.2 milliseconds relative to the second drive signal. In this case, the signal processing circuit 130 can send the second drive signal to the air conduction sound component 120 at time T0, and while sending the second drive signal, buffer the first drive signal and, after buffering for the delay period (0.2 ms), send the first drive signal to the bone conduction sound component 110. For example, referring to Figure 7, the signal processing circuit sends the first drive signal to the bone conduction sound component 110 at time T6, where T6 - T0 = 0.2 ms. Thus, at 500 Hz, the bone conduction sound wave generated by the bone conduction sound component 110 is the same as the air conduction sound wave generated by the air conduction sound component 120, or the time difference between the two is small (less than or equal to 1 ms).

[0120] As shown in FIG7 , by buffering the first drive signal for 0.2 milliseconds before sending it, the signal processing circuit 130 can delay sending the first drive signal by 0.2 milliseconds relative to the second drive signal. This ensures that at the target frequency of 500 Hz, the bone conduction sound wave and the air conduction sound wave are generated at the same time, or the time difference between the two is small (less than or equal to 1 ms). This avoids the problem of sound distortion.

[0121] Figure 8 shows a schematic diagram of delaying the transmission of the second drive signal. Assuming the target frequency is 2000 Hz, the signal processing circuit 130, using the method described above, can determine that the second drive signal needs to be delayed by 0.85 milliseconds relative to the first drive signal. In this case, the signal processing circuit 130 can send the first drive signal to the bone conduction sound component 110 at time T0, and simultaneously buffer the second drive signal while sending the first drive signal. After buffering for the delay period (0.85 ms), the second drive signal is sent to the air conduction sound component 120. In other words, the signal processing circuit 130 sends the second drive signal to the air conduction sound component 120 at time T7, where T7 - ​​T0 = 0.85 ms. Thus, at 2000 Hz, the bone conduction sound wave generated by the bone conduction sound component 110 coincides with the air conduction sound wave generated by the air conduction sound component 120, or the time difference between the two is small (less than or equal to 1 ms).

[0122] As shown in FIG8 , by buffering the second drive signal for 0.85 milliseconds before sending it, the signal processing circuit 130 can delay sending the second drive signal by 0.85 milliseconds relative to the first drive signal. This ensures that at the target frequency of 2000 Hz, the bone conduction sound wave and the air conduction sound wave are generated at the same time, or the time difference between the two is small (less than or equal to 1 ms). This avoids the problem of sound deviation.

[0123] FIG9 shows a schematic diagram of the system architecture of another acoustic device 300 provided according to an embodiment of the present specification. As shown in FIG9 , the acoustic device 300 may include a bone conduction sound component 110, an air conduction sound component 120, and a signal processing circuit 130. Among them, the signal processing circuit 130 may include: at least one storage medium 210 and at least one processor 220. It should be noted that, for the purpose of demonstration only, the signal processing circuit 130 in this application includes at least one storage medium 210 and at least one processor 220. It can be understood by those skilled in the art that the signal processing circuit 130 may also include other hardware circuit structures, which are not limited in this application, as long as they can meet the functions mentioned in this application without deviating from the spirit of this application.

[0124] Continuing with FIG9 , in some embodiments, the acoustic device 300 may further include a communication port 230. The communication port 230 is used for data communication between the acoustic device and the outside world. For example, the communication port 230 may be used for data communication between the acoustic system and other devices / systems. In some embodiments, the acoustic device 300 may further include an internal communication bus 240. The internal communication bus 240 may connect different system components. For example, the bone conduction sound component 110, the air conduction sound component 120, the processor 220, the storage medium 210, and the communication port 230 may all be connected via the internal communication bus 240.

[0125] 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 method provided in this application. The signal processing method will be introduced later.

[0126] At least one processor 220 is used to execute the at least one instruction set mentioned above. When the acoustic system 003 is running, the 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 in this application. 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 device 300 shown in Figure 9 illustrates a case where only one processor 220 is included. However, it should be noted that the acoustic device 300 provided in the present application may also include multiple processors. Therefore, the operations and / or method steps disclosed in the present application may be performed by a single processor or jointly by multiple processors. For example, if the processor 220 of the acoustic device 300 in the present application 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).

[0127] FIG10 is a flow chart illustrating a signal processing method P400 according to an embodiment of this specification. The signal processing circuit 130 may be configured to execute the signal processing method P400. Specifically, the processor 220 in the signal processing circuit 130 reads at least one instruction set stored in the memory 210 and executes the signal processing method P400 according to the instructions of the at least one instruction set.

[0128] As shown in FIG10 , the signal processing method P400 may include:

[0129] S410: Obtain an audio signal.

[0130] S420: Generate a first driving signal based on the first component of the audio signal and send the signal to the bone conduction sound component to drive the bone conduction sound component to convert the first driving signal into bone conduction sound waves.

[0131] S430: Generate a second driving signal based on the second component of the audio signal and send the signal to the air conduction sound component to drive the air conduction sound component to convert the second driving signal into air conduction sound waves.

[0132] One of the first drive signal and the second drive signal is sent with a delay relative to the other, so that at at least some frequencies, the bone-conducted sound wave is generated at a first moment and the air-conducted sound wave is generated at a second moment, and the time difference between the first moment and the second moment is less than or equal to 100 microseconds.

[0133] In some embodiments, the at least part of the frequencies includes a target frequency, and the target frequency is a frequency corresponding to an intersection of frequency response curves of the bone-conducted sound wave and the air-conducted sound wave.

[0134] In some embodiments, the first time delay varies with the frequency of the bone conduction sound wave, and the second time delay varies with the frequency of the air conduction sound wave; and the method further includes: determining the time delay difference information corresponding to the target frequency, the time delay difference information representing the difference between the first time delay generated by the bone conduction sound component at the target frequency and the second time delay generated by the air conduction sound component at the target frequency, and based on the time delay difference information, determining whether to delay sending the first drive signal relative to the second drive signal, or determining whether to delay sending the second drive signal relative to the first drive signal, and based on the time delay difference information, determining the delay duration corresponding to the delayed sending.

[0135] In some embodiments, the delayed sending of the first drive signal relative to the second drive signal includes: sending the second drive signal to the air conduction sound component; and caching the first drive signal while sending the second drive signal, and sending the first drive signal to the bone conduction sound component after caching the delay time.

[0136] In some embodiments, the delayed sending of the second drive signal relative to the first drive signal includes: sending the first drive signal to the bone conduction sound component; and caching the second drive signal while sending the first drive signal, and sending the second drive signal to the air conduction sound component after caching the delay time.

[0137] In some embodiments, determining the delay difference information corresponding to the target frequency includes: obtaining a pre-stored correspondence relationship, the correspondence relationship including multiple candidate frequencies and the delay difference information corresponding to each candidate frequency; and querying the correspondence relationship based on the target frequency to obtain the delay difference information corresponding to the target frequency.

[0138] In some embodiments, the delay difference information corresponding to each candidate frequency is obtained by testing in the following manner: generating a single-frequency tone test signal corresponding to the candidate frequency; sending the single-frequency tone test signal to the bone conduction pronunciation component to obtain a first test delay generated when the bone conduction pronunciation component converts the single-frequency tone test signal into a bone conduction test sound wave; sending the single-frequency tone test signal to the air conduction pronunciation component to obtain a second test delay generated when the air conduction pronunciation component converts the single-frequency tone test signal into an air conduction test sound wave; and generating the delay difference information corresponding to the candidate frequency based on the first test delay and the second test delay.

[0139] In some embodiments, the first component corresponds to a mid-high frequency component in the audio signal; and the second component corresponds to a mid-low frequency component in the audio signal.

[0140] In some embodiments, generating the first drive signal based on the first component of the audio signal includes: filtering the audio signal through a first filter to obtain the first component, the first filter being configured to allow the mid- and high-frequency components in the audio signal to pass through, and generating the first drive signal based on the first component; and generating the first drive signal based on the first component of the audio signal includes: filtering the audio signal through a second filter to obtain the second component, the second filter being configured to allow the mid- and low-frequency components in the audio signal to pass through, and generating the second drive signal based on the second component.

[0141] It should be noted that the specific implementation method and technical effects of the signal processing method P400 provided in this specification can be found in the relevant description above and will not be repeated here.

[0142] On the other hand, this specification provides a non-transitory storage medium that stores at least one set of executable instructions for 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 P400 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 device, the program code is used to cause the acoustic device to perform the steps of the signal processing method P400 described in this specification. The program product for implementing the above method can use a portable compact disk read-only memory (CD-ROM) to include program code and can be run on the acoustic device. 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 or in combination with an instruction execution system. 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 of the present specification 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 device, partially on the acoustic device, as a stand-alone software package, partially on the acoustic device and partially on a remote computing device, or entirely on the remote computing device.

[0143] 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.

[0144] 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.

[0145] 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.

[0146] 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. The content of each sub-embodiment is also valid even when it includes fewer than all the features of a single previously disclosed embodiment.

[0147] Each patent, patent application, patent application publication, and other materials, such as articles, books, specifications, publications, documents, articles, and the like, cited herein, except to the extent that it is inconsistent or conflicting with this document or that it has 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 description, definition, and / or use of a term in any material and the description, definition, and / or use of a term in this document, the term in this document shall control.

[0148] 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 device, characterized in that: include: The bone conduction pronunciation component generates a first time delay when converting the first driving signal into a bone conduction sound wave; an air conduction sound generation component, which generates a second time delay when converting a second driving signal into an air conduction sound wave, wherein an absolute value of a difference between the second time delay and the first time delay is greater than 100 microseconds; and The signal processing circuit is connected to the bone conduction pronunciation component and the air conduction pronunciation component in communication, and when in operation: Get the audio signal, generating the first driving signal based on the first component of the audio signal and sending the first driving signal to the bone conduction sound producing component to drive the bone conduction sound producing component to convert the first driving signal into the bone conduction sound wave, and generating the second driving signal based on the second component of the audio signal and sending the second driving signal to the air conduction sound component to drive the air conduction sound component to convert the second driving signal into the air conduction sound wave, One of the first drive signal and the second drive signal is sent with a delay relative to the other, so that at least part of the frequency, the bone conduction sound wave is generated at a first moment and the air conduction sound wave is generated at a second moment, and the time difference between the first moment and the second moment is less than or equal to 100 microseconds.

2. The acoustic device according to claim 1, characterized in that The at least part of the frequencies includes a target frequency, and the target frequency is a frequency corresponding to an intersection point of frequency response curves of the bone conduction sound wave and the air conduction sound wave.

3. The acoustic device according to claim 2, characterized in that The first time delay varies with the frequency of the bone-conducted sound wave, and the second time delay varies with the frequency of the air-conducted sound wave; and The signal processing circuit is further configured to: Determine the time delay difference information corresponding to the target frequency, wherein the time delay difference information represents the difference between the first time delay generated by the bone conduction pronunciation component at the target frequency and the second time delay generated by the air conduction pronunciation component at the target frequency, Based on the delay difference information, determining to delay sending the first drive signal relative to the second drive signal, or determining to delay sending the second drive signal relative to the first drive signal, and Based on the delay difference information, a delay duration corresponding to the delayed sending is determined.

4. The acoustic device according to claim 3, characterized in that In order to achieve delayed sending of the first driving signal relative to the second driving signal, the signal processing circuit: sending the second driving signal to the air conduction sound generation component; as well as The first driving signal is buffered while the second driving signal is sent, and the first driving signal is sent to the bone conduction sound producing component after buffering the delay time.

5. The acoustic device according to claim 3, characterized in that In order to achieve delayed transmission of the second driving signal relative to the first driving signal, the signal processing circuit: Sending the first driving signal to the bone conduction sound producing component; as well as The second driving signal is buffered while the first driving signal is sent, and the second driving signal is sent to the air conduction sound generation component after buffering the delay time.

6. The acoustic device according to claim 3, characterized in that In order to determine the delay difference information corresponding to the target frequency, the signal processing circuit: Obtaining a pre-stored corresponding relationship, where the corresponding relationship includes at least one candidate frequency and delay difference information corresponding to each candidate frequency; as well as The corresponding relationship is queried based on the target frequency to obtain delay difference information corresponding to the target frequency.

7. The acoustic device according to claim 6, characterized in that The delay difference information corresponding to each candidate frequency is obtained by testing in the following way: generating a single-frequency tone test signal corresponding to the candidate frequency; Sending the single-frequency tone test signal to the bone conduction sounding component to obtain a first test delay generated when the bone conduction sounding component converts the single-frequency tone test signal into a bone conduction test sound wave; sending the single-frequency tone test signal to the air conduction sound component to obtain a second test delay generated when the air conduction sound component converts the single-frequency tone test signal into an air conduction test sound wave; and Delay difference information corresponding to the candidate frequency is generated based on the first test delay and the second test delay.

8. The acoustic device according to claim 2, characterized in that The target frequency is 2000 Hz or 500 Hz.

9. The acoustic device according to claim 1, characterized in that The at least part of the frequency includes frequencies in a frequency interval [freq, 2*freq], wherein the freq is a frequency corresponding to an intersection point of voltage curves of the first drive signal and the second drive signal.

10. The acoustic device according to claim 1, characterized in that The first component corresponds to the mid-high frequency component in the audio signal; and The second component corresponds to a mid- and low-frequency component in the audio signal.

11. The acoustic device according to claim 10, characterized in that In order to generate the first driving signal, the signal processing circuit: filtering the audio signal through a first filter to obtain the first component, wherein the first filter is configured to allow the mid-high frequency components in the audio signal to pass through, and generating the first drive signal based on the first component; and In order to generate the second driving signal, the signal processing circuit: filtering the audio signal through a second filter to obtain the second component, wherein the second filter is configured to allow the mid- and low-frequency components in the audio signal to pass through, and The second drive signal is generated based on the second component.

12. The acoustic device according to claim 1, characterized in that The air conduction pronunciation component at least comprises: Air conduction speakers, and a digital power amplifier connected to an input terminal of the air conduction speaker; and The bone conduction pronunciation component at least comprises: Bone conduction speakers, and The analog power amplifier is connected to the input end of the bone conduction speaker.

13. A signal processing method, characterized in that: Applied to an acoustic device, the acoustic device includes a bone conduction pronunciation component, an air conduction pronunciation component and a signal processing circuit, the bone conduction pronunciation component generates a first time delay when converting a first drive signal into a bone conduction sound wave, the air conduction pronunciation component generates a second time delay when converting a second drive signal into an air conduction sound wave, and the absolute value of the difference between the second time delay and the first time delay is greater than 100 microseconds, and the method includes: Obtaining an audio signal; Generate the first driving signal based on the first component of the audio signal and send it to the bone conduction sound producing component to drive the bone conduction sound producing component to convert the first driving signal into the bone conduction sound wave; as well as generating the second driving signal based on the second component of the audio signal and sending the second driving signal to the air conduction sound component to drive the air conduction sound component to convert the second driving signal into the air conduction sound wave, One of the first drive signal and the second drive signal is sent with a delay relative to the other, so that at least part of the frequency, the bone conduction sound wave is generated at a first moment and the air conduction sound wave is generated at a second moment, and the time difference between the first moment and the second moment is less than or equal to 100 microseconds.

14. The method according to claim 13, characterized in that The at least part of the frequencies includes a target frequency, and the target frequency is a frequency corresponding to an intersection point of frequency response curves of the bone conduction sound wave and the air conduction sound wave.

15. The method according to claim 14, characterized in that The first time delay varies with the frequency of the bone-conducted sound wave, and the second time delay varies with the frequency of the air-conducted sound wave; and The method further comprises, by the signal processing circuit: Determine the time delay difference information corresponding to the target frequency, wherein the time delay difference information represents the difference between the first time delay generated by the bone conduction pronunciation component at the target frequency and the second time delay generated by the air conduction pronunciation component at the target frequency, Based on the delay difference information, determining to delay sending the first drive signal relative to the second drive signal, or determining to delay sending the second drive signal relative to the first drive signal, and Based on the delay difference information, a delay duration corresponding to the delayed sending is determined.

16. The method according to claim 15, characterized in that The delaying the sending of the first driving signal relative to the second driving signal comprises: sending the second driving signal to the air conduction sound generating component; and The first driving signal is buffered while the second driving signal is sent, and the first driving signal is sent to the bone conduction sound producing component after buffering the delay time.

17. The method according to claim 15, characterized in that The delaying sending of the second driving signal relative to the first driving signal comprises: sending the first driving signal to the bone conduction sound producing component; and The second driving signal is buffered while the first driving signal is sent, and the second driving signal is sent to the air conduction sound generation component after buffering the delay time.

18. The method according to claim 15, characterized in that The determining the delay difference information corresponding to the target frequency includes: Obtaining a pre-stored corresponding relationship, the corresponding relationship including a plurality of candidate frequencies and delay difference information corresponding to each candidate frequency; and The corresponding relationship is queried based on the target frequency to obtain delay difference information corresponding to the target frequency.

19. The method according to claim 18, characterized in that The delay difference information corresponding to each candidate frequency is obtained by testing in the following way: generating a single-frequency tone test signal corresponding to the candidate frequency; Sending the single-frequency tone test signal to the bone conduction sounding component to obtain a first test delay generated when the bone conduction sounding component converts the single-frequency tone test signal into a bone conduction test sound wave; sending the single-frequency tone test signal to the air conduction sound component to obtain a second test delay generated when the air conduction sound component converts the single-frequency tone test signal into an air conduction test sound wave; and Delay difference information corresponding to the candidate frequency is generated based on the first test delay and the second test delay.

20. The method according to claim 13, characterized in that The at least part of the frequency includes frequencies in a frequency interval [freq, 2*freq], wherein the freq is a frequency corresponding to an intersection point of voltage curves of the first drive signal and the second drive signal.

21. The method according to claim 13, characterized in that The first component corresponds to the mid-high frequency component in the audio signal; and The second component corresponds to a mid- and low-frequency component in the audio signal.

22. The method according to claim 21, characterized in that The generating the first drive signal based on the first component of the audio signal comprises: filtering the audio signal through a first filter to obtain the first component, wherein the first filter is configured to allow the mid-high frequency components in the audio signal to pass through, and generating the first drive signal based on the first component; and The generating the first drive signal based on the first component of the audio signal comprises: filtering the audio signal through a second filter to obtain the second component, wherein the second filter is configured to allow the mid- and low-frequency components in the audio signal to pass through, and The second drive signal is generated based on the second component.

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