RU2792614C1 - Systems and methods for noise reduction using su-bband noise reduction technique - Google Patents

Abstract

FIELD: acoustics.

SUBSTANCE: technical result is achieved due to the noise reduction system, which includes a sub-band noise sensor, a plurality of sub-band suppression modules and an output module. The sub-band noise sensor may be configured to detect noise and generate a plurality of sub-band noise signals in response to the detected noise. Each of the plurality of sub-band noise signals may have a different sub-band of the noise band. Each of the sub-band noise canceling modules may be configured to receive one of the sub-band noise signals from the sub-band noise sensor and generate a sub-band noise correction signal to reduce the received sub-band noise signal. The output module may be configured to receive sub-band noise correction signals and output a noise correction signal for noise reduction based on the sub-band noise correction signals.

EFFECT: increasing of the effect of noise reduction.

9 cl, 17 dwg

Description

The technical field to which the invention belongs

The present disclosure relates generally to noise reduction, and in particular to noise reduction systems and methods using subband noise reduction technology.

State of the art

Noise canceling is often needed to suppress noise (for example, unwanted sound that is unpleasant, loud, or interferes with listening). Conventionally, noise may be passively reduced, such as by eliminating (or partially eliminating) the source of the noise, blocking the transmission of the noise, and/or preventing the user's ear from hearing the noise, or the like. or any combination of them. These noise reduction technologies can be passive and give poor noise reduction effect under some conditions (for example, when the noise has a low frequency below the threshold frequency). Recently, active noise reduction (ANR) technology has been adopted to reduce noise in an active manner by generating a noise reduction signal (eg, a signal having an inverse phase with respect to the noise to be reduced). A conventional ANR device can use a full-band noise reduction technology that generates a single noise correction signal with a bandwidth that overlaps the noise bandwidth for noise suppression. The subband decomposition method can be used in noise reduction to improve the noise reduction effect. Thus, it is desirable to provide systems and methods for noise reduction using a subband noise reduction method.

Disclosure of the essence of the invention

Noise reduction system provided. The system may include a subband noise sensor, a plurality of subband noise reduction modules, and an output module. The subband noise sensor may be configured to detect noise and generate a plurality of subband noise signals in response to the detected noise. Each of the subband noise signals may have a different subband from the noise band. Each of the subband noise canceling modules may be configured to receive one of the subband noise signals from the subband noise sensor and generate a subband noise correction signal to reduce the received subband noise signal. The output module may be configured to receive subband noise correction signals and output a noise correction signal for noise reduction based on the subband noise correction signals.

In some embodiments, the subband noise sensor may include an acoustoelectric transducer and a band splitter. The acoustic transducer may be configured to detect noise and convert the noise into an electrical signal. The band splitter may be connected to an acoustoelectric transducer and configured to split the electrical signal into subband noise signals.

In some embodiments, the band splitter may include a plurality of band pass filters. Each of the bandpass filters may have a unique frequency response and be configured to generate one of the subband noise signals.

In some embodiments, the first bandpass filter of the bandpass filters may have a first frequency response and may be configured to generate a first subband noise signal from the subband noise signals. The second bandpass filter of the bandpass filters may have a second frequency response and may be configured to generate a second subband noise signal from the subband noise signals. The second subband noise signal may be adjacent to the first subband noise signal among the subband noise signals in the frequency domain. The first frequency response and the second frequency response may intersect at a frequency point that is adjacent to at least one of the first frequency response half power point or the second frequency response half power point.

In some embodiments, the first frequency response of the first bandpass filter and the second frequency response of the second bandpass filter may have the same bandwidth or different bandwidths.

In some embodiments, the subband noise reduction module may be integrated into the band separation module.

In some embodiments, the subband noise sensor may include a plurality of acoustoelectric transducers and a plurality of samplers. Each of the acoustoelectric transducers may have a unique frequency response and may be configured to generate an electrical subband noise signal through noise processing. Each of the sampling modules may be configured to receive one electrical subband noise signal from the electrical subband noise signals and sample the received electrical subband noise signal to generate one subband noise signal from the electrical subband noise signals.

In some embodiments, an acoustoelectric transducer of acoustoelectric transducers may include an acoustic channel component and a sound sensitive component. The acoustic channel component may be configured to filter noise to generate subband noise. The sound sensitive component may be configured to convert the subband noise into an electrical subband noise signal.

In some embodiments, an acoustoelectric transducer of acoustoelectric transducers may include a sound sensitive component. The sound sensitive component may be configured to convert the noise into an electrical subband noise signal.

In some embodiments, the first acoustoelectric transducer of the acoustoelectric transducers may have a first frequency response and may be configured to generate an electrical subband noise signal corresponding to the first subband noise signal from the subband noise signals. The second acoustoelectric transducer of the acoustoelectric transducers may have a second frequency response and may be configured to generate an electrical subband noise signal corresponding to a second subband noise signal from the subband noise signals. The second subband noise signal may be adjacent to the first subband noise signal among the subband noise signals in the frequency domain. The first frequency response and the second frequency response may intersect at a frequency point that is adjacent to at least one of the first frequency response half power point or the second frequency response half power point.

In some embodiments, the first frequency response of the first acoustoelectric transducer and the second frequency response of the second acoustoelectric transducer have the same bandwidth or different bandwidths.

In some embodiments, the subband noise signal bands produced by the subband noise sensor may overlap the noise band.

In some embodiments, at least one subband noise reduction module of the subband noise reduction modules may include a phase modulator and an amplitude modulator. The phase modulator may be configured to receive a corresponding subband noise signal and generate a phase modulated signal by modulating the phase of the corresponding subband noise signal. The amplitude modulator may be configured to receive a phase modulated signal from the phase modulator and generate a subband noise correction signal to reduce the corresponding subband noise signal by modulating the amplitude of the phase modulated signal.

In some embodiments, phase modulation of the corresponding subband noise signal may include inverting the phase of the corresponding subband noise signal and optionally compensating for the phase offset of the corresponding subband noise signal as it is transmitted from the subband noise sensor to the phase modulator.

In some embodiments, at least one subband noise reduction module of the subband noise reduction modules may include an amplitude modulator and a phase modulator. The amplitude modulator may be configured to receive a corresponding subband noise signal and generate an amplitude modulated signal by modulating the amplitude of the corresponding subband noise signal. The phase modulator may be configured to receive an amplitude modulated signal from the amplitude modulator and generate a subband noise correction signal to reduce the corresponding subband noise signal by modulating the phase of the amplitude modulated signal.

In some embodiments, phase modulation of the amplitude modulated signal may include inverting the phase of the amplitude modulated signal and optionally compensating for the phase offset of the corresponding subband noise signal as it is transmitted from the subband noise sensor to the phase modulator.

In some embodiments, the noise correction signal may include subband noise correction signals. An output module may include a plurality of output blocks. Each of the output units may be configured to receive one of the subband noise correction signals generated by the subband noise cancellation modules and output the received subband noise correction signal.

In some embodiments, the output module may be configured to receive subband noise correction signals from the subband noise cancellation modules. The output module may also be configured to combine the subband noise correction signals to generate a noise correction signal. The output module may also be configured to output the noise correction signal.

In some embodiments, the implementation of the noise may include environmental noise.

In some embodiments, the system may further include a residual noise sensor and a residual noise reduction module. The residual noise sensor may be configured to detect residual noise and generate a residual noise signal in response to the detected residual noise. The distance between the residual noise sensor and the output module may be less than the distance between the subband noise sensor and the output module. The residual noise reduction module may be configured to receive the residual noise signal and generate a residual noise correction signal to reduce the residual noise.

In some embodiments, the output module may be further configured to receive the residual noise correction signal and output the residual noise correction signal. The system may further include a second output module, configured to receive the residual noise correction signal and output the residual noise correction signal.

In some embodiments, the residual noise signal generated by the residual noise sensor may include a plurality of residual subband noise signals, and the residual noise correction signal may include a plurality of residual subband noise correction signals. Each of the residual subband noise correction signals may be configured to reduce one of the residual subband noise signals.

In some embodiments, the system may include a residual noise sensor and a feedback module. The residual noise sensor may be configured to detect residual noise and generate a residual noise signal in response to the detected residual noise. The distance between the residual noise sensor and the output module may be less than the distance between the subband noise sensor and the output module. The feedback module may be configured to adjust the subband squelch modules in accordance with the residual noise.

In some embodiments, the subband noise sensor may be installed near or within the output module, and the noise may include residual noise.

In some embodiments, the subband noise signals may be analog signals, and the subband noise cancellation modules may include analog signal processing components.

In some embodiments, the subband noise signals may be digital signals, and the subband noise reduction modules may include digital signal processing components.

In some embodiments, the output module may include an electro-acoustic transducer configured to convert the noise correction signal into an audio signal and output the audio signal.

In some embodiments, the output module may include a signal processing unit and an electro-acoustic transducer. The signal processing unit may be configured to process the noise correction signal. The acoustic transducer may be configured to convert the processed noise correction signal into an audio signal and output the audio signal.

Additional features will be set forth in part in the following description, and in part will become apparent to those skilled in the art upon reading the following description with reference to the accompanying drawings, or may be learned using or working with the examples provided. Features of the present disclosure may be practiced and achieved using various aspects of the methodologies, tools, and combinations set forth in the detailed examples below.

Brief description of the drawings

The present disclosure is further described in terms of exemplary embodiments. These exemplary embodiments are described in detail with reference to the drawings. These embodiments are non-limiting exemplary embodiments in which like reference numerals represent like structures in multiple drawing views and in which:

1A is a schematic diagram illustrating an exemplary noise reduction system according to some embodiments of the present disclosure;

1B is a schematic diagram illustrating an exemplary noise reduction system according to some embodiments of the present disclosure;

2 is a schematic diagram illustrating an exemplary noise canceling device according to some embodiments of the present disclosure;

3 is a schematic diagram illustrating an exemplary noise canceling device according to some embodiments of the present disclosure;

4 is a schematic diagram illustrating an example of a subband noise sensor according to some embodiments of the present disclosure;

FIG. 5A shows an exemplary frequency response of a first band pass filter and an exemplary frequency response of a second bandpass filter of a band splitter, according to some embodiments of the present disclosure;

figv - the frequency response of the first bandpass filter (figure 5), and another exemplary frequency response of the second bandpass filter (figure 5) according to some embodiments of the present disclosure;

6 is a schematic diagram illustrating an exemplary subband noise sensor according to some embodiments of the present disclosure;

7 is a schematic diagram illustrating an exemplary subband noise reduction module according to some embodiments of the present disclosure;

8 is a schematic diagram illustrating an exemplary phase modulated signal according to some embodiments of the present disclosure;

9 is a schematic diagram illustrating an exemplary subband noise reduction module according to some embodiments of the present disclosure;

10 is a schematic diagram illustrating an example of a subband noise sensor according to some embodiments of the present disclosure;

11 is a schematic diagram illustrating an exemplary noise reduction system according to some embodiments of the present disclosure;

12 is a schematic diagram illustrating an exemplary noise reduction system according to some embodiments of the present disclosure;

13 is a schematic diagram illustrating an exemplary noise reduction system according to some embodiments of the present disclosure;

14 is a schematic diagram illustrating an exemplary noise reduction system according to some embodiments of the present disclosure; And

15 is a schematic diagram illustrating an exemplary noise reduction system according to some embodiments of the present disclosure.

Implementation of the invention

In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the related disclosure. However, those skilled in the art will appreciate that the present disclosure may be practiced without such details. In other instances, well-known methods, procedures, systems, components, and/or circuits have been described at a relatively high level without detail in order to avoid over-complicating aspects of the present disclosure. Various modifications to the disclosed embodiments will be 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 the present disclosure. Thus, the present disclosure is not limited to the embodiments shown, and is to be within the broadest scope of the claims.

It should be noted that the terms "system", "mechanism", "unit", "module" and/or "device" as used herein are one way of distinguishing between the various components, elements, parts, sections or assemblies of different levels in the order increase. However, terms may be replaced by other expressions if they serve the same purpose.

It should be noted that when a block, mechanism, module or device is referred to as "connected to", "connected to" or "associated with" another block, mechanism, module or device, it may be directly connected to or connected to another block, mechanism , module, or block, or an intermediate block, mechanism, module, or device may be present unless the context clearly indicates otherwise. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.

The terminology used herein is for the purpose of describing specific examples and embodiments only and is not intended to be limiting. As used herein, the singular forms may also mean the inclusion of plural forms, unless the context clearly dictates otherwise. In addition, it should be understood that as used in this disclosure, the terms "includes" and/or "comprises" indicate the presence of integers, devices, modes, declared functions, steps, elements, operations and/or components, but do not exclude the presence or adding one or more other integers, devices, characteristics, functions, steps, elements, operations, components, and/or groups thereof.

Spatial and functional relationships between elements (eg, between layers) are described using various terms, including "connected", "engaged", "coupled" and "coupled". In the present disclosure, if the relationship between the first and second elements is not explicitly indicated as "direct", then this relationship includes a direct relationship in which there are no other intermediate elements between the first and second elements, as well as an indirect relationship in which there are no other intermediate elements between the first and second elements. and the second elements present (spatially or functionally) one or more intermediate elements. In contrast, when an element is referred to as "directly" connected, involved, conjugated, or associated with another element, there are no intermediate elements. In addition, the spatial and functional relationship between elements can be achieved in various ways. For example, a mechanical connection between two elements may include a welded connection, a keyed connection, a pin connection, an interference connection, and the like. or any combination of them. Other words used to describe the relationship between elements should be interpreted in a similar way (eg, "between" or "directly between", "adjacent" or "immediately adjacent", etc.).

One aspect of the present disclosure relates to a noise reduction system. The noise reduction system may include a subband noise sensor, a plurality of subband suppression modules, and an output module. The subband noise sensor may be configured to detect noise and generate a plurality of subband noise signals in response to the detected noise. Each of the plurality of subband noise signals may have a different subband of the noise band. Each of the subband noise canceling modules may be configured to receive one of the subband noise signals from the subband noise sensor and generate a subband noise correction signal to reduce the received subband noise signal. The output module may be configured to receive subband noise correction signals and output the noise correction signal for noise reduction.

According to some embodiments of the present disclosure, a system may reduce noise using a subband noise reduction method that can perform noise reduction on multiple subbands of a noise band. Compared with the full-band noise reduction technology, which performs noise reduction directly in the entire noise band, the sub-band noise reduction method can improve the noise reduction effect. In some embodiments, the noise reduction system may be used in various scenarios to reduce various types of noise. For example, an audio broadcast device may include an environmental noise reduction device for reducing environmental noise and a residual noise cancellation device for reducing residual noise after environmental noise cancellation, each or one of which may be implemented with one or more noise cancellation system components. described above. The combination of the environmental noise reduction device and the residual noise suppression device can effectively reduce unwanted sound, thereby improving the performance of the audio broadcasting device.

FIG. 1A is a schematic diagram illustrating an exemplary noise reduction system 100A according to some embodiments of the present disclosure. The noise reduction system 100A may be configured to reduce or suppress noise (eg, unwanted sound that is unpleasant, loud, or interferes with listening). The noise canceling system 100A can be applied to various areas and/or devices such as headphones (eg, noise canceling headphones, bone conduction headphones), a noise suppressor, an anti-snoring device, and the like. or any combination of them. In some embodiments, the noise cancellation system 100A may be an active noise cancellation system that reduces noise by generating a noise cancellation signal designed to reduce noise (eg, a signal that has an inverted phase with respect to noise).

As shown in FIG. 1A, the noise canceling system 100A may include an environmental noise reducer 120, a residual noise reducer 150, and an output unit 170. In some embodiments, two or more components of noise cancellation system 100A may be connected to and/or interact with each other. For example, each of the environmental noise reduction devices 120 and the residual noise reduction device 150 may be electrically connected to the output module 170 . As used herein, a connection between two components may include a wireless connection, a wired connection, any other communication connection that allows the transmission and/or reception of data, and/or any combination of these connections. The wireless connection may include, for example, a Bluetooth™ link, a Wi-Fi™ link, a WiMax™ link, a WLAN link, a ZigBee link, a mobile network link (e.g., 3G, 4G, 5G, etc.). .), or the like, or a combination thereof. The wired connection may include, for example, a coaxial cable, a communication cable (such as a telecommunications cable), a flexible cable, a spiral cable, a non-metallic sheath cable, a metal sheath cable, a multi-core cable, a twisted pair cable, a ribbon cable, a shielded cable , two-core cable, optical fiber, electric cable, optical cable, telephone wire, etc. or any combination of them.

The environmental noise reducer 120 may be configured to reduce environmental noise 110 . For example, as shown in FIG. 1A, the environmental noise reduction device 120 may detect environmental noise 110 and generate an environmental noise correction signal 130 to reduce environmental noise 110. As used herein, the term "ambient noise 110" can refer to any sound other than the desired sound. For example, environmental noise 110 may include background audio (eg, traffic noise, wind noise, water noise, extraneous speech) that is present when the user is wearing an audio broadcast device (eg, headphones). The ambient noise 110 can be detected by the ambient noise reduction device 120 when the audio broadcasting device is playing sound (eg, music) or not playing sound.

In some embodiments, the ambient noise canceling device 120 may be configured to reduce the ambient noise 110 in accordance with a full-band noise cancellation method or a sub-band noise cancellation method. A full-band noise reduction method may refer to a method that reduces noise by generating a single noise correction signal with a bandwidth that overlaps that of the original noise. For example, the noise correction signal may be an analog signal or a digital signal having an inverse phase with respect to the noise. The subband noise cancellation technology may refer to a technology that can reduce noise by generating a plurality of subband noise correction signals. Each of the subband noise correction signals may have a different subband of the noise band (i.e., a band that is narrower than and within the noise band) and may be configured to reduce a noise portion that has a different other subband.

In some embodiments, environmental noise reduction device 120 may include one or more components for implementing subband noise reduction technology. For example, the environmental noise reduction apparatus 120 may include a first subband noise sensor and a plurality of first subband noise canceling modules. The first subband noise sensor may be configured to detect environmental noise 110 and generate a plurality of environmental subband noise signals. The bandwidth of each subband environmental noise signal may be narrower than and within the bandwidth of the environmental noise 110. The frequency bands of different subband environmental noise signals may differ from each other. The first subband noise canceling modules may be configured to generate a plurality of subband environmental noise correction signals based on the subband environmental noise signals. Each of the subband environmental noise correction signals may be an analog signal or a digital signal used to reduce one of the subband environmental noise signals. The subband environmental noise correction signals may form an environmental noise correction signal 130 or may be processed (eg, combined) to generate an environmental noise correction signal 130 . In some embodiments, the ambient noise reduction device 120 may be implemented as a noise canceling device 200 having one or more components as shown in FIG. 2.

As shown in FIG. 1, the environmental noise correction signal 130 generated by the environmental noise reduction device 120 may be transmitted to the output unit 170 for output. The output module 170 may include an electro-acoustic transducer (eg, speaker, audio player) that may convert an electrical signal into an audio signal to suppress environmental noise 110 . For example, the environmental noise correction signal 130 may be the first combined signal from the environmental subband noise correction signals. The output unit 170 may directly convert the first combined signal into an audio signal for output. Alternatively, output module 170 may include a signal processing unit and an electro-acoustic transducer. The signal processing unit may be configured to process the first combined signal, and the electro-acoustic transducer may be configured to convert the processed first combined signal into an audio signal for output. By way of example only, the first combined signal may be a digital signal. The signal processing unit may convert the first combined signal into a pulse width modulation (PWM) signal or an analog signal. The acoustic transducer can further convert the PWM signal or analog signal into audio for output. In some alternative embodiments, the signal processing unit of output module 170 may be integrated into device 120 to reduce environmental noise. The environment noise reduction apparatus 120 may process the first combined signal and pass the processed first combined signal to the output unit 170 for output.

In some embodiments, the environmental noise correction signal 130 may include a plurality of environmental subband noise correction signals as described above. The output module 170 may include a plurality of output units, each of which may include an electro-acoustic transducer and optionally a signal processing unit. Each of the environmental subband noise correction signals may be transmitted in parallel to one of the output units for output. The output of the subband environmental noise correction signal by the output unit may be performed similarly to the first combined signal of the subband environmental noise correction signals by the output unit 170 as described above.

The ambient noise reduction audio signal 110 output by the output module 170 may interact with the ambient noise 110, where the interference may cancel or partially cancel the environmental noise 110, as shown in FIG. 1A by a dashed line connecting the audio signal output from the output module 170 and the noise 110 environment. In some embodiments, residual noise 140 may be present after environmental noise cancellation 110. Residual noise reduction device 150 may serve as a feedback mechanism for noise reduction system 100A to reduce residual noise 140. For example, as shown in FIG. 1A, residual noise reduction device 150 may detect residual noise 140 and generate a residual noise correction signal 160 to reduce residual noise. 140.

In some embodiments, the residual noise reduction device 150 may be configured to reduce the residual noise 140 in accordance with a full band noise reduction technology or a subband noise reduction technology as discussed above. For example, the residual noise reduction device 150 may produce a single residual noise correction signal 160 that has the same bandwidth as the residual noise 140, but with reversed phase, to reduce the residual noise 140. As another example, the residual noise cancellation device 150 may include one or more components for implementing subband noise reduction technology, such as a second subband noise sensor and a plurality of second subband noise reduction modules. The distance between the sensor of the second sub-band noise may be less than the distance between the sensor of the environmental noise reduction device 120 for measuring the environmental noise 110 (e.g., the first sub-band noise sensor as described above) so that the second sub-band noise sensor can detect residual noise 140. In response to residual noise 140, the second subband noise sensor may generate a plurality of residual subband noise signals, each of which may have a different subband of the residual noise bandwidth 140. Every second subband noise cancellation module may be configured to receive one of residual subband noise signals from the second subband noise sensor; and generating a residual subband noise correction signal to reduce the received residual subband noise signal. The residual subband noise correction signals may form a residual noise correction signal 160 or may be processed (eg, combined) to generate a residual noise correction signal 160. In some embodiments, residual noise reduction device 150 may be implemented as noise canceling device 200 having one or more of the components shown in FIG. 2 and/or a residual noise reduction device 150C having one or more of the components shown in FIG. 14.

The residual noise correction signal 160 generated by the residual noise reduction apparatus 150 may be transmitted to the output unit 170 for output. The output of the residual noise correction signal 160 may be implemented similarly to the output of the environmental noise correction signal 130 as described above. For example, output module 170 may convert the residual noise correction signal 160 into an audio signal for residual noise reduction 140. The audio signal for residual noise reduction 140 may be output along with the audio signal for environmental noise reduction 110 as described above. An audio signal to reduce residual noise 140 may interact with residual noise 140, as shown in FIG. 1A by a dashed line connecting the audio signal output by output module 170 and residual noise 140. In some embodiments, output module 170 may separately output noise correction signal 130 environment and signal 160 correction of residual noise. Alternatively, the environmental noise correction signal 130 and the residual noise correction signal 160 may be combined to produce a second combined signal that may be further output by output module 170 to cancel environmental noise 110 and residual noise 140.

In some alternative embodiments, instead of generating the residual noise correction signal 160, the residual noise reduction device 150 may provide a feedback signal to the environmental noise reduction device 120 in accordance with the detected residual noise 140. For example, the feedback signal may be generated by the feedback module of the device. 150 to reduce residual noise and include information related to residual noise 140. The environmental noise reducer 120 may adjust another parameter related to the generation of the environmental noise correction signal 130 so that an adjusted correction signal 130 can be generated. environmental noise to more effectively suppress environmental noise 110 . As another example, the feedback signal may include an instruction directing the environmental noise reduction device 120 to adjust one or more parameters related to generating the environmental noise correction signal 130 . Additional descriptions regarding the feedback module and/or adjustment of one or more parameters related to the generation of the environmental noise correction signal 130 can be found elsewhere in this disclosure. See, for example, Fig. 13 and its corresponding description.

In some embodiments, noise reduction system 100A may be applied to an audio broadcast device. The noise reduction component 100A can be installed anywhere in the audio broadcasting device. For example, the environmental noise reduction device 120 or part thereof (eg, the environmental noise detection sensor 110) may be installed outside the audio broadcast device. The output module 170 may be installed inside the audio broadcast device. The output module 170 may be configured to output the noise correction signal(s) and optionally serve as an output component of an audio broadcasting device to output a desired sound (eg, music). The residual noise reduction device 150 or a portion thereof (eg, a residual noise detection sensor 140) may be installed near or within the output module 170.

FIG. 1B is a schematic diagram illustrating an exemplary noise reduction system 100B according to some embodiments of the present disclosure. The noise reduction system 100B may be similar to the noise reduction system 100A described with reference to FIG. 1A, except that the noise reduction system 100B may include an output module 170 and an additional output module 180. As shown in FIG. 1B, the output module 170 may be electrically connected to the environmental noise reduction device 120 to output the environmental noise correction signal 130. The output module 180 may be electrically connected to the residual noise reduction device 150 to output the residual noise correction signal 160.

It should be noted that the above description of noise cancellation systems 100A and 100B is intended to be illustrative and not to limit the scope of the present disclosure. Many alternatives, modifications and variations will be apparent to those skilled in the art. Features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to provide additional and/or alternative exemplary embodiments. For example, noise reduction system 100A and/or noise reduction system 100B may include one or more additional components. Additionally or alternatively, one or more of the components of noise reduction system 100A and/or noise reduction system 100B described above may be omitted. For example, one of the environmental noise reduction device 120 and the residual noise reduction device 150 may be omitted. As another example, two or more components of noise reduction system 100A and/or noise reduction system 100B may be combined into one component. By way of example only, in noise reduction system 100B, output module 170 may be integrated into device 120 to reduce environmental noise, and/or output module 180 may be integrated into device 150 to reduce residual noise.

FIG. 2 is a schematic diagram illustrating an exemplary noise canceling device 200 according to some embodiments of the present disclosure. The squelch device 200 may be configured to squelch 210 using subband noise cancellation technology as described elsewhere in this disclosure (eg, see FIG. 1A and the related description).

As shown in FIG. 2, the noise canceling device 200 may include a subband noise sensor 220, a plurality of subband noise canceling modules 230, and an integrated module 240. The noise canceling device 200 may be connected to the output module 170. Bandpass noise sensor 220 may be configured to detect noise 210 (eg, environmental noise 110 or residual noise 140 as described with reference to FIG. 1) and generate a plurality of subband noise signals (eg, subband noise signals S1-Sm) in response to the detected noise. "m" can be any positive integer greater than 1, such as 5, 10, 15, and so on.

Noise 210 may be an audio signal having a specific bandwidth. The subband noise signal may refer to a signal having a narrower bandwidth than, and within, the noise bandwidth 210. For example, noise 210 may have a frequency band ranging from 10 Hz to 30,000 Hz. The bandwidth of the subband noise signal may be 100-200 Hz, which is within the bandwidth of the noise 210. In some embodiments, the combination of the bandwidths of the subband noise signals may span the bandwidth of the noise 210. Additionally or alternatively, at least two of the subband noise signals may have different frequency bands. If desired, each of the subband noise signals may have a distinct frequency band different from one or more frequency bands of one or more other subband noise signals. Different subband noise signals may have the same bandwidth or different bandwidths. In some embodiments, overlap between frequency bands of a pair of adjacent subband noise signals in the frequency domain can be avoided in order to improve the noise reduction effect. In this document, two subband noise signals whose center frequencies are adjacent to each other among the subband noise signals can be considered as adjacent to each other in the frequency domain. Additional description regarding the frequency bands of a pair of adjacent subband noise signals can be found elsewhere in this disclosure. See, for example, FIGS. 5A and 5B and their respective descriptions.

In some embodiments, the subband noise signals generated by the subband noise sensor 220 may be digital signals or analog signals. For illustrative purposes, unless otherwise indicated or evident from the context, the present disclosure has been described with reference to subband noise signals as digital signals and is not intended to limit the scope of the present disclosure. In some embodiments, subband noise sensor 220 may include one or more components, as shown in FIG. 4, which may be configured to convert noise 210 into an electrical signal and separate the electrical signal into subband noise signals. Alternatively, the subband noise sensor 220 may include one or more components, as shown in FIG. 6, that may be configured to generate a plurality of electrical subband noise signals by processing the noise 210 and sampling the electrical subband noise signals to generate subband noise signals. noise. Additional description regarding subband noise sensor 220 can be found elsewhere in this disclosure. See, for example, figures 4-6 and their respective description.

The subband noise reduction modules 230 may include a subband noise reduction module 230-1, a subband noise reduction module 230-2, ... and a subband noise reduction module 230-m as shown in FIG. In some embodiments, the number (or number) of subband noise canceling modules 230 may be equal to the number (or number) of subband noise signals produced by the subband noise sensor 220. Each of the subband noise canceling modules 230 may be configured to receive one of the subband noise signals from the subband noise sensor 220 and generate a subband noise correction signal to reduce the received subband noise signal. For example, as shown in FIG. 2, the subband noise cancellation module 230-i (where i is a positive integer equal to or less than m) may receive the subband noise signal Si from the subband noise sensor 220 and generate a subband noise correction signal Ci to reduce the signal Si subband noise.

In some embodiments, the subband noise signals may be transmitted via parallel transmitters from the subband noise sensor 220 to the subband noise cancellation modules 230 . If necessary, the subband noise signal may be transmitted by a transmitter according to a specific communication protocol for digital signal transmission. Exemplary communication protocols may include the Audio Engineering Society (AES3), European Broadcast Union (EBU), AES/EBU, Automatic Data Accumulator and Transfer (ADAT), inter-integrated audio interface I (Inter-IC Sound, 2S), Time Division Multiplexing (TDM), Musical Instrument Digital Interface (MIDI), CobraNet, Ethernet Audio/Video Bridging, Ethernet AVB), Dante, International Telecommunication Union (ITU)-T G.728, ITU-T G.711, ITU-T G.722, ITU-T G.722.1, ITU-T G.722.1 Appendix C , advanced audio coding (Advanced Audio, AAC)-LD, etc. or their combination. The digital signal can be transmitted in a certain format, including Compact Disc (CD), WAVE, Audio Interchange File Format (AIFF), MPEG (Moving Picture Experts Group)-1, MPEG-2, MPEG-3, MPEG-4, Musical Instrument Digital Interface (MIDI), Windows Audio File Format (Windows Media Audio, WMA), RealAudio, Vector Quantization with Transform Domains and Weighted Interleaving (Transform- domain Weighted Interleave Vector Quantization VQF), Adaptive Multi-Rate (AMR), APE, Free Lossless Audio Codec (FLAC), Advanced Audio Coding (AAC), etc. . or their combination. In some alternative embodiments, the sub-band noise signals may be converted to a single-channel signal using, for example, a frequency division multiplexing technique and transmitted to the sub-band noise reduction modules 230.

In some embodiments, the subband noise cancellation module 230-i may phase modulate and/or amplitude modulate the subband noise signal Si to generate a corresponding subband noise correction signal Ci. In some embodiments, phase modulation and amplitude modulation may be performed sequentially or simultaneously with the subband noise signal Si. For example, the subband noise canceling module 230-i may first phase modulate the subband noise signal Si to generate a phase modulated signal, and then amplitude modulate the phase modulated signal to generate a corresponding subband noise correction signal Ci. Phase modulation of the subband noise signal Si may include inverting the phase of the subband noise signal Si. If desired, in some embodiments, a phase shift (or shift) of the noise 210 may occur during its transmission from a location in the subband noise sensor 220 to a location in the output module 170 (e.g., from a location outside the audio broadcast device to a location in a loudspeaker inside the audio broadcast device) . Phase modulation of the subband noise signal Si may further include compensating for a phase offset of the subband noise signal Si during signal transmission. Alternatively, the subband noise canceling module 230-i may first amplitude modulate the subband noise signal Si to generate an amplitude modulated signal, and then phase modulate the amplitude modulated signal to generate a subband noise correction signal Ci. Additional descriptions relating to the subband noise reduction module 230-i can be found elsewhere in this disclosure. See, for example, FIGS. 7-9 and their respective descriptions.

Combiner 240 may be configured to combine the subband noise correction signals to generate a noise correction signal, as shown in FIG. Combiner 240 may include any component that can combine multiple signals. For example, combiner 240 may generate a mixed signal (ie, a noise correction signal) in accordance with a signal combining method such as a frequency channel multiplexing method. In some alternative embodiments, combiner 240 may be an independent component or part of a component (eg, output module 170) other than noise canceler 200. Alternatively, the combiner 240 may be omitted, and the subband noise correction signals may be transmitted in parallel to the output module 170 for output, as described with reference to FIG.

The output module 170 may be configured to receive a noise correction signal from the combined module 240. The output of the noise correction signal by the output module 170 may be performed similarly to the environmental noise correction signal 130 as described with reference to FIG. 1A. For example, the output unit 170 may convert the noise correction signal into an audio signal for output, or process the noise correction signal and convert the processed noise correction signal into an audio signal for output.

In some embodiments, one or more components of noise reduction system 100A (or noise reduction system 100B) may be implemented on one or more components of noise reduction device 200, respectively or together. For example, the device 120 for reducing environmental noise may be implemented using one or more components of the device 200 for noise reduction. The subband noise sensor 220 of the environmental noise reduction apparatus 120 may be located at a distance greater than a threshold distance from the environmental noise detection output module 170 . By way of example only, the subband noise sensor 220 may be installed outside the audio broadcast device, and the output module 170 may be installed inside the audio broadcast device. Additionally or alternatively, the residual noise reduction device 150 may be implemented by one or more components of the noise canceling device 200. The subband noise sensor 220 of the residual noise reduction device 150 may be installed near or within the output module 170 (eg, located within a threshold distance of the output module 170) to detect residual noise in the noise reduction. For example, subband noise sensor 220 and output module 170 may be installed side by side in an audio broadcasting device.

FIG. 3 is a schematic diagram illustrating an exemplary noise canceling device 300 according to some embodiments of the present disclosure. The noise canceling device 300 may be similar to the noise canceling device 200 except for some components or features. As shown in FIG. 3, the output module 170 may include a plurality of output modules 170-1, 170-2, ... and 170-m. The subband noise correction signals generated by the subband noise canceling modules 230 may be transmitted to the output units 170 in parallel without being combined. Each of the output units may be configured to receive one of the subband noise correction signals and output the received subband noise correction signal. In some embodiments, similar to noise canceling device 200, noise canceling device 300 may be used to implement one or more components of noise canceling system 100A (or noise canceling system 100B), such as noise canceling device 120 and/or residual noise reduction device 150.

It should be noted that the above description of the noise canceling devices 200 and 300 is intended to be illustrative and not to limit the scope of the present disclosure. Many alternatives, modifications and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to provide additional and/or alternative exemplary embodiments. For example, noise canceling device 200 and/or noise canceling device 300 may include one or more additional components. Additionally or alternatively, one or more components of the noise canceling device 200 and/or noise canceling device 300 described above, such as an integrated module 240, may be omitted. As another example, two or more components of the noise canceling device 200 and/or or system 300 noise reduction. By way of example only, the combining module 240 and/or the output module 170 of the noise canceling device 200 may be integrated into the subband noise canceling module 230 of the noise canceling device 200 .

4 is a schematic diagram illustrating an exemplary subband noise sensor 220A according to some embodiments of the present disclosure. Subband noise sensor 220A may be an exemplary embodiment of subband noise sensor 220 as described with reference to FIG. As shown in FIG. 4, the subband noise sensor 220A may include an AE transducer 410 and a band splitter 420 connected to the AE transducer 410.

Electroacoustic transducer 410 may be configured to detect noise 210 and convert noise 210 into an electrical signal. The bandwidth of the electrical signal may be the same (or substantially the same) as the noise 210. Electro-acoustic transducer 410 may include a microphone, hydrophone, acousto-optic modulator (AOM), or any other device that can convert audio signals into electrical signals or any combination of them.

Band splitter 420 may be configured to split the electrical signal into a plurality of subband noise signals (eg, subband noise signals S1-Sm). In some embodiments, band splitter 420 may include a plurality of bandpass filters. Each of the bandpass filters may have a unique frequency response and may be configured to generate one of the subband noise signals by processing the electrical signal. The frequency response of a bandpass filter may refer to the score of the bandpass filter's output spectrum (ie, the corresponding subband noise signal) in response to an input signal (ie, an electrical signal). For example, the frequency response of a bandpass filter may include a center frequency, a bandwidth, a cutoff frequency, and the like. or any combination of them.

In some embodiments, the aggregation of the subband noise signal bands may span the noise band 210. The bandwidths of different subband noise signals may be the same or different from each other. Additionally or alternatively, overlap between frequency bands of a pair of adjacent sub-band noise signals in the frequency domain can be avoided. To this end, in some embodiments, the frequency responses of two bandpass filters that produce a pair of adjacent subband noise signals may intersect at a certain frequency point that satisfies a certain condition.

For illustrative purposes, FIG. 5A shows an exemplary first bandpass filter response 510 and an exemplary second bandpass filter response 520 according to some embodiments of the present disclosure. FIG. 5B shows a first bandpass filter frequency response 510 and another exemplary second bandpass filter response 530 according to some embodiments of the present disclosure. The first band pass filter may be configured to process the electrical signal generated by the acoustoelectric transducer 410 to generate a first subband noise signal from the subband noise signals. The second bandpass filter may be configured to process the electrical signal generated by the acoustoelectric transducer 410 to generate a second subband noise signal from the subband noise signals. The second subband noise signal may be adjacent to the first subband noise signal among the subband noise signals in the frequency domain.

половинной мощности, верхнюю точку

половинной мощности и центральную частоту

. Используемая в данном документе точка половинной мощности определенной частотной характеристики может относиться к точке частоты с определенным ослаблением уровня мощности (например, -3 дБ). Ширина полосы частот частотной характеристики 510 может быть равна разности между

и

. Частотная характеристика 520 второго полосового фильтра имеет нижнюю точку

половинной мощности, верхнюю точку

половинной мощности и центральную частоту

. Ширина полосы частот частотной характеристики 520 может быть равна разности между

и

. Ширины полосы частот первого и второго полосовых фильтров могут быть равны друг другу.In some embodiments, the frequency responses of the first and second bandpass filters may have the same bandwidth. For example, as shown in FIG. 5A, the frequency response 510 of the first band pass filter has a low point

half power, high point

half power and center frequency

. As used herein, the half power point of a specific frequency response may refer to a frequency point with a specific power attenuation (eg, -3 dB). The bandwidth of the frequency response 510 may be equal to the difference between

And

. The frequency response 520 of the second band pass filter has a low point

half power, high point

half power and center frequency

. The bandwidth of the frequency response 520 may be equal to the difference between

And

. The bandwidths of the first and second bandpass filters may be equal to each other.

половинной мощности, верхнюю точку

половинной мощности (которая больше чем

) и центральную частоту

. Ширина полосы частот частотной характеристики 530 второго полосового фильтра может быть равна разности между

и

, которая может быть больше, чем у частотной характеристики 510 первого полосового фильтра. Таким образом, в модуле 420 разделения полосы частот может потребоваться меньшее количество полосовых фильтров для выработки множества сигналов субполосного шума для охвата полосы частот шума 210.Alternatively, the frequency responses of the first and second band pass filters may have different bandwidths. For example, as shown in FIG. 5B, the frequency response 530 of the second band pass filter has a low point

half power, high point

half power (which is more than

) and center frequency

. The bandwidth of the frequency response 530 of the second bandpass filter may be equal to the difference between

And

, which may be greater than the frequency response 510 of the first bandpass filter. Thus, fewer band pass filters may be required in the band splitter 420 to generate multiple subband noise signals to cover the noise band 210.

половинной мощности частотной характеристики 510, которая также является нижней точкой половинной мощности частотной характеристики 520. Используемая в данном документе точка частоты может считаться близкой к точке половинной мощности, если разность уровней мощности между точкой частоты и точкой половинной мощности не превышает порогового значения (например, 2 дБ). В таких случаях могут быть меньшие потери или повторение энергии в частотных характеристиках первого и второго полосовых фильтров, что может привести к надлежащему диапазону перекрытия между частотными характеристиками первого и второго полосовых фильтров. В некоторых вариантах осуществления диапазон перекрытия может считаться относительно небольшим, когда частотные характеристики пересекаются в точке частоты с уровнем мощности больше -5 дБ и/или меньше -1 дБ. В некоторых вариантах осуществления центральные частоты и/или ширины полосы пропускания частотных характеристик первого и второго полосовых фильтров могут быть отрегулированы для получения более узкого или надлежащего диапазона перекрытия между частотными характеристиками первого и второго полосовых фильтров во избежание перекрытия между полосами частот первого и второго сигналов субполосного шума. В некоторых вариантах осуществления частотная характеристика модуля 420 разделения полосы частот может иметь флуктуации уровня мощности в пределах ±1 дБ.In some embodiments, the frequency responses of the first bandpass filter and the second bandpass filter may intersect at a certain frequency point. In some embodiments, the specific frequency point where the frequency responses of the first and second bandpass filters intersect may be near the half power point of the first bandpass filter and/or the half power point of the second bandpass filter. Taking FIG. 5A as an example, frequency response 510 and frequency response 520 intersect at the top point

half power of the frequency response 510, which is also the low point of the half power of the frequency response 520. As used herein, the frequency point can be considered close to the half power point if the power level difference between the frequency point and the half power point does not exceed a threshold value (e.g., 2 dB). In such cases, there may be less loss or repetition of energy in the frequency responses of the first and second bandpass filters, which may result in a proper range of overlap between the frequency responses of the first and second bandpass filters. In some embodiments, the overlap range may be considered relatively small when the frequency responses intersect at a frequency point with a power level greater than -5 dB and/or less than -1 dB. In some embodiments, the center frequencies and/or bandwidths of the frequency responses of the first and second bandpass filters may be adjusted to provide a narrower or appropriate range of overlap between the frequency responses of the first and second bandpass filters to avoid overlap between the bands of the first and second subband noise signals. . In some embodiments, the frequency response of the band splitter 420 may have fluctuations in the power level within ±1 dB.

It should be noted that the examples shown in FIGS. 5A and 5B are intended to be illustrative and not to limit the scope of the present disclosure. A person skilled in the art can make numerous changes and modifications in accordance with the ideas of the present disclosure. However, these variations and modifications are not outside the scope of this disclosure. For example, one or more parameters (eg, bandwidth, high half power point, low half power point, and/or center frequency) of the frequency response of the first bandpass filter and/or the second bandpass filter may be variable.

In some embodiments, the bandpass filters of the bandsplitter 420 may include a Butterworth filter, a Chebyshev filter, a Cauer filter, and the like. or any combination of them. The slope of the frequency response of a bandpass filter may be related to the type and/or order of the bandpass filter. For example, the slope of a Butterworth filter of a certain order may be larger than that of a Chebyshev filter of the same order. The steepness of the front of a Chebyshev filter of a certain order may be greater than that of a Cauer filter of the same order. For a particular bandpass filter having a particular center frequency, the slope of the bandpass filter's frequency response may increase with the order of the bandpass filter. In some embodiments, the band pass filter type of the band splitter 420 may be selected according to the bandwidth of the noise 210 to be reduced. For example, to suppress noise with a narrow bandwidth (for example, with a bandwidth less than the first threshold bandwidth), such as low-frequency noise or high-frequency noise with a narrow bandwidth, a band pass filter having a high order (for example, , an order above a threshold order) and a narrow bandwidth (eg, a bandwidth less than a second threshold bandwidth). The first and second threshold bandwidths may be the same or different from each other.

In some embodiments, the bandpass filter of the bandsplitter 420 may be a finite impulse response filter whose impulse response has a finite duration, or an infinite impulse response filter that depends linearly on a finite number of input samples and a finite number of previous filter outputs.

In some embodiments, the subband noise signals generated by the band splitter 420 may be output in parallel (eg, through multiple electrical cables) for further processing. For example, each bandpass filter of the subband splitter 420 may be electrically coupled to a subband noise reduction module (e.g., subband noise reduction module 230), wherein the subband noise signal produced by the bandpass filter may be transmitted to the connected subband noise reduction module to generate a corresponding subband noise correction signal. Alternatively, the sub-band noise signals may be processed to produce a single-channel signal using, for example, a frequency division multiplexing technique, and output for further processing. In some embodiments, a plurality of subband noise reduction modules may be integrated into the band splitter 420. The integrated band splitter can generate subband noise signals and further generate a plurality of subband noise correction signals to reduce the subband noise signals. Additional description relating to the integrated frequency division module can be found elsewhere in this disclosure. See, for example, Fig. 10 and its corresponding description.

It should be noted that the above description of the subband noise sensor 220A is intended to be illustrative and not to limit the scope of the present disclosure. Many alternatives, modifications and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to provide additional and/or alternative exemplary embodiments. For example, subband noise sensor 220A may include one or more additional components. Additionally or alternatively, one or more components of the subband noise sensor 220A described above may be omitted. As another example, two or more subband noise sensor components 220A may be integrated into one component.

FIG. 6 is a schematic diagram illustrating an example of a subband noise sensor 220B according to some embodiments of the present disclosure. Subband noise sensor 220B may be an exemplary embodiment of subband noise sensor 220 as described with reference to FIG. Subband noise sensor 220B may be configured to detect noise 210 and generate a plurality of subband noise signals (e.g., subband noise signals S1-Sm) in response to the detected noise 210.

As shown in FIG. 6, subband noise sensor 220B may include a plurality of AE transducers 610 (e.g., AE transducers 610-1 - 610-m) and a plurality of samplers 620 (e.g., samplers 620-1 - 620-m) . Each of the AM transducers 610 may have a unique frequency response and may be configured to generate an electrical subband noise signal by noise processing 210. The electrical subband noise signals generated by the AM transducers 610 may be analog signals. Each of the sampling modules 620 may be configured to receive one of the electrical subband noise signals and sample the received electrical subband noise signal to generate one subband noise signal from the subband noise signals (ie, a digital signal).

In some embodiments, the number (or number) of acoustoelectric transducers 610 and the number (or number) of samplers 620 may equal the number (or number) of subband noise signals (ie, m). The value of m may be related to the noise bandwidth 210 and the bandwidths of the generated subband noise signals. For example, a certain number of acoustoelectric transducers 610 may be omitted such that the combining of the subband noise signal bands may overlap the noise band 210. Additionally or alternatively, overlap between the bands of a pair of adjacent subband noise signals among the subband noise signals may be avoided.

In some embodiments, the acoustoelectric transducer 610 may include an acoustic channel component and a sound sensitive component. The acoustic channel component may form the path through which the audio signal (eg, noise 210) is transmitted to the audio component. For example, an acoustic channel component may include one or more chamber structures, one or more tubular structures, and the like. or their combination. The sound sensitive component may convert an audio signal transmitted from the acoustic channel component (eg, original noise 210 or processed noise after passing through the acoustic channel component) into an electrical signal. For example, sound sensitive component 420 may include a diaphragm, plate, cantilever, and so on. Taking the circuit as an example, a diaphragm can be used to convert the change in sound pressure caused by the audio signal on the surface of the diaphragm into mechanical vibration of the diaphragm. The sound sensitive component may be made from one or more materials including, for example, plastic, metal, piezoelectric material, and the like. or any composite material.

In some embodiments, the frequency response of the acoustic transducer 610 may be related to the acoustic structure of the acoustic channel component of the acoustic transducer 610. sound sensitive component of the acoustoelectric transducer 610-i. In some embodiments, the acoustic structure of the acoustic channel component may have a certain acoustic impedance such that the acoustic channel component may function as a noise filter 210 to generate subband noise. The sound sensitive component of the acoustoelectric transducer 610-i can then convert the subband noise into an electrical subband noise signal Ei.

In some embodiments, the acoustic impedance of the acoustic structure may be set according to the noise bandwidth 210. In some embodiments, the acoustic structure, primarily including the chamber structure, may function as a high-pass filter, while the acoustic structure primarily including a tubular structure, can function as a low-pass filter. By way of example only, the acoustic duct component may have a tube-shaped chamber structure. The chamber-tube design can be a series combination of sound volume and acoustic mass, and an inductor-capacitor (LC) resonant circuit can be formed. If an acoustically impeding material is used in the conduit chamber design, a series resistor-inductor-capacitor (RLC) circuit can be formed, and the acoustic impedance of the series RLC circuit can be determined according to equation (1), as shown below:

, (1)

, (1)

относится к акустическому импедансу компонента акустического канала,

относится к угловой частоте конструкции камеры-трубы,

относится к мнимой единице,

относится к акустической массе,

относится к звуковой мощности,

относится к акустическому сопротивлению последовательного контура RLC.Where

refers to the acoustic impedance of the acoustic channel component,

refers to the angular frequency of the chamber-tube design,

refers to the imaginary unit,

refers to the acoustic mass,

refers to sound power,

refers to the acoustic impedance of the series RLC circuit.

. Центральную частоту

полосового фильтра F1 можно регулировать путем регулировки акустической массы

и/или звуковой мощности

. Например, центральная частота

полосового фильтра F1 может быть определена в соответствии с уравнением (2), как показано ниже:The chamber-tube design can function as a band pass filter (designated as F1). Band pass filter F1 can be adjusted by adjusting the acoustic impedance

. center frequency

bandpass filter F1 can be adjusted by adjusting the acoustic mass

and/or sound power

. For example, the center frequency

bandpass filter F1 can be determined according to equation (2) as shown below:

. (2)

. (2)

In some embodiments, the frequency response of the acoustic-electric transducer 610 may be associated with a physical characteristic (e.g., material, design) of the sound-sensitive component of the electro-acoustic transducer 610. A sound-sensitive component having a specific physical characteristic may be sensitive to a certain frequency band of noise 210. multiple elements in a sound sensitive component may cause change(s) in the electrical parameter(s) of the sound sensitive component. The audio sensitive component may be sensitive to a certain frequency band of the audio signal. The bandwidth of the audio signal can cause corresponding changes in the electrical parameters of the sound sensitive component. In other words, the circuit may function as a filter that processes a subband of the audio signal. In some embodiments, noise 210 may be transmitted to the sound sensitive component via the acoustic channel component without (or substantially without) filtering by the acoustic channel component. The physical characteristic of the sound sensitive component can be adjusted so that the sound sensitive component can function as a filter that filters noise 210 and converts the filtered noise into an electrical subband noise signal.

полосового фильтра F2 может быть определена в соответствии с уравнением (3), как показано ниже:By way of example only, the sound sensitive component may include a diaphragm that may function as a bandpass filter (denoted F2). Center frequency

bandpass filter F2 can be determined according to equation (3) as shown below:

, (3)

, (3)

относится к массе диафрагмы,

относится к коэффициенту упругости диафрагмы,

относится к демпфированию диафрагмы. Ширина полосы пропускания полосового фильтра F2 может регулироваться путем регулировки

. Центральную частоту

полосового фильтра F2 можно отрегулировать путем регулировки массы диафрагмы и/или коэффициента упругости диафрагмы.Where

refers to the mass of the diaphragm,

refers to the coefficient of elasticity of the diaphragm,

refers to diaphragm damping. The bandwidth of the F2 bandpass filter can be adjusted by adjusting

. center frequency

The bandpass filter F2 can be adjusted by adjusting the mass of the diaphragm and/or the coefficient of elasticity of the diaphragm.

и/или

) или параметра(ов) звукочувствительного компонента (например,

и/или

). В некоторых альтернативных вариантах осуществления объединение компонента акустического канала и звукочувствительного компонента может функционировать как фильтр. Путем изменения параметров компонента акустического канала и звукочувствительного компонента можно соответствующим образом отрегулировать частотную характеристику комбинации компонента акустического канала и звукочувствительного компонента. Дополнительное описание, касающееся компонента акустического канала и/или звукочувствительного компонента, который функционирует как полосовой фильтр, можно найти, например, в заявке РСТ № PCT/CN2018/105161, поданной 12 сентября 2018 года под названием «SIGNAL PROCESSING DEVICE HAVING MULTIPLE ACOUSTIC-ELECTRIC TRANSDUCERS», содержание которого включено в данный документ путем ссылки.As described above, the acoustic channel component or the sound sensitive component of the acoustoelectric transducer 610 may function as a filter. The frequency response of the acoustoelectric transducer 610 can be adjusted by changing the parameter(s) of the acoustic channel component (e.g.,

and/or

) or parameter(s) of the sound sensitive component (for example,

and/or

). In some alternative embodiments, the combination of the acoustic channel component and the sound sensitive component may function as a filter. By changing the parameters of the acoustic channel component and the sound sensitive component, the frequency response of the combination of the acoustic channel component and the sound sensitive component can be appropriately adjusted. Further description regarding an acoustic channel component and/or a sound sensitive component that functions as a bandpass filter can be found, for example, in PCT Application No. PCT/CN2018/105161 filed on September 12, 2018 under the title "SIGNAL PROCESSING DEVICE HAVING MULTIPLE ACOUSTIC-ELECTRIC TRANSDUCERS", the contents of which are incorporated herein by reference.

In some embodiments, the acoustoelectric transducers 610 may have specific frequency responses such that the subband noise signal bands generated by the subband noise sensor 220B can overlap the noise band 210 and/or overlap between the bands of a pair of adjacent subband noise signals can be avoided. To this end, in some embodiments, the frequency responses of the acoustoelectric transducers 610 that correspond to a pair of adjacent subband noise signals may have the same or similar characteristics as those of the bandpass filters that produce the pair of adjacent subband noise signals, as described with reference to FIG. 4.

For example, among the ac transducers 610, the first ac transducer having a first frequency response may produce an electrical subband noise signal that corresponds to the first subband noise signal of the subband noise. The second acoustoelectric transducer having the second frequency response may generate an electrical subband noise signal that corresponds to a second subband noise signal adjacent to the first subband noise signal in the frequency domain. The first frequency response and the second frequency response may intersect at a frequency point that is adjacent to the half power point of the first frequency response and/or the half power point of the second frequency response. By way of example only, the first frequency response of the first acoustoelectric transducer may be similar to the frequency response 510 of the first band pass filter as shown in FIGS. 5A and 5B. The second frequency response of the second acoustoelectric transducer may be similar to the frequency response 520 of the second bandpass filter as shown in FIG. 5A or the frequency response 530 of the second bandpass filter as shown in FIG. 5B.

In some embodiments, the acoustoelectric transducer 610 may transmit the generated electrical subband noise signal to a sampler 620 via one or more transmitters. An exemplary transmitter can be a coaxial cable, a communication cable (e.g., a telecommunications cable), a flexible cable, a spiral cable, a non-metallic sheath cable, a metal sheath cable, a multicore cable, a twisted pair cable, a ribbon cable, a shielded cable, a two-core cable, an optical fiber, and the like, or combinations thereof. In some embodiments, the electrical subband noise signals may be transmitted to sampler 620 via a plurality of subband transmitters connected in parallel. Each of the plurality of subband transmitters may be connected to the ac transducer 610 and transmit the electrical subband noise signal generated by the ac transducer 610 to a respective sampler 620 . Alternatively, the subband noise signals may be converted to a single channel signal using, for example, frequency division multiplexing technology and transmitted to sampling units 620 via a single transmitter.

In some embodiments, sampling module 620 may sample the electrical subband noise signal using a specific sampling rate. In some embodiments, the sampling rates of different sampling modules 620 may be the same. For example, a particular electrical subband noise signal may have the highest center frequency of all electrical subband noise signals, and the sampling rate of each sampler 620 may be more than twice the highest frequency in the band of the particular electrical subband noise signal. This avoids signal distortion and frequency aliasing between the sub-band noise signals produced by sampling units 620. However, the use of a high sampling rate (eg, a sampling rate above the threshold frequency) may result in increased computational load and/or time.

), частота

дискретизации электрического сигнала Ei субполосного шума может быть определена в соответствии с уравнением (4), как показано ниже:Alternatively, the sampling rates of the different sampling units 620 may be different according to the frequency bands of the electrical sub-band noise signals to be sampled. For example, the sampling rate of sampling module 620-i may be more than twice the highest frequency in the subband noise electrical signal Ei band. In some embodiments, sampling module 620-i may sample the electrical subband noise signal Ei in accordance with a bandpass sampling method. For example, the sampling rate of sampling module 620-i may be at least twice the subband noise electrical signal bandwidth Ei and/or at most four times the subband noise electrical signal bandwidth Ei. As another example, assuming that the subband noise electrical signal bandwidth Ei is (

), frequency

The sampling electrical signal Ei of the subband noise can be determined according to Equation (4) as shown below:

, Уравнение (4)

, Equation (4)

может быть наибольшим целым числом, которое делает определяемую

, равной или большей, чем

. Используя технологию полосовой дискретизации, а не технологию широкополосной дискретизации или технологию дискретизации нижних частот, модуль 620-i дискретизации может выполнять дискретизацию электрического сигнала Ei субполосного шума с относительно низкой частотой дискретизации, тем самым уменьшая сложность и стоимость процесса дискретизации, а также повышая качество дискретизации.Where

can be the largest integer that makes the specified

equal to or greater than

. By using bandpass sampling technology rather than wideband sampling technology or low-pass sampling technology, the sampling unit 620-i can sample the electrical subband noise signal Ei at a relatively low sampling rate, thereby reducing the complexity and cost of the sampling process, as well as improving the sampling quality.

In some embodiments, subband noise signals produced by samplers 620 with different sample rates may have different sample periods. A plurality of subband noise canceling modules (eg, subband noise canceling modules 230) may receive subband noise signals from subband noise sensor 220B and generate a plurality of subband noise correction signals. The subband noise correction signals may have different sampling periods. The subband noise correction signals may need to be combined to produce a noise correction signal according to some embodiments of the present disclosure, as described elsewhere in this disclosure (eg, see FIG. 2 and related description). Before combining, the subband noise correction signals may be downsampled or upsampled so that the sampling periods of the subband noise correction signals can be adjusted to the same value.

It should be noted that the above description of the subband noise sensor 220B is intended to be illustrative and not to limit the scope of the present disclosure. Many alternatives, modifications and variations will be apparent to those skilled in the art. Features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to provide additional and/or alternative exemplary embodiments. For example, one or more components of the subband noise sensor 220B described above may be omitted. In some embodiments, acoustoelectric transducers 610 may directly generate subband noise signals as digital signals through noise processing 210, and samplers 620 may be omitted. Additionally or alternatively, subband noise sensor 220B may include one or more additional components.

из датчика субполосного шума (например, датчика 220 субполосного шума) и выработки сигнала

коррекции субполосного шума для уменьшения сигнала 220 субполосного шума

.

может относиться к коэффициенту затухания амплитуды, относящемуся к шуму (например, шуму 210), который необходимо уменьшить.FIG. 7 is a schematic diagram illustrating an exemplary subband noise reduction module 700 according to some embodiments of the present disclosure. Subband squelch module 700 may be an exemplary embodiment of subband squelch module 230-i as described with reference to FIGS. 2 and 3. Subband squelch module 700 may be configured to receive a subband noise signal.

from a subband noise sensor (eg, subband noise sensor 220) and signal generation

subband noise correction to reduce the subband noise signal 220

.

may refer to an amplitude attenuation factor related to noise (eg, noise 210) to be reduced.

субполосного шума и выработки фазомодулированного сигнала

путем инверсии фазы сигнала

субполосного шума. Например, как показано на фиг.8, фазомодулированный сигнал

может иметь инвертированную фазу по отношению к сигналу

субполосного шума. В некоторых вариантах осуществления смещение фазы (или сдвиг) шума может происходить во время его передачи из местоположения в датчике субполосного шума, который вырабатывает сигнал

субполосного шума в местоположение в модуле вывода (например, модуле 170 вывода) или его части (например, блоке вывода). В некоторых вариантах осуществления фазовым сдвигом можно пренебречь. Фазовый модулятор 710 может вырабатывать фазомодулированный сигнал

, просто выполняя инверсию фазы сигнала

субполосного шума. Звук может передаваться в виде плоской волны в наружном слуховом проходе, если частота звука ниже частоты среза наружного слухового прохода. В иллюстративных целях наружный слуховой проход можно рассматривать как трубчатый канал определенного радиуса, и его граничную частоту можно определить в соответствии с уравнением (5), как показано ниже:As shown in FIG. 7, the subband noise canceling module 700 may include a phase modulator 710 and an amplitude modulator 720. The phase modulator 710 may be configured to receive a signal

subband noise and phase modulated signal generation

by inverting the phase of the signal

subband noise. For example, as shown in Fig. 8, the phase modulated signal

may have an inverted phase with respect to the signal

subband noise. In some embodiments, a phase shift (or shift) of the noise may occur during its transmission from a location in the subband noise sensor that generates the signal

subband noise to a location in an output module (eg, output module 170) or a portion thereof (eg, output unit). In some embodiments, the implementation of the phase shift can be neglected. Phase modulator 710 can produce a phase modulated signal

, by simply performing a phase inversion of the signal

subband noise. Sound can be transmitted as a plane wave in the external auditory canal if the sound frequency is below the cutoff frequency of the external auditory canal. For illustrative purposes, the external auditory meatus can be considered as a tubular canal of a certain radius, and its cutoff frequency can be determined in accordance with equation (5), as shown below:

, Уравнение (5)

, Equation (5)

относится к частоте среза наружного слухового прохода,

относится к скорости звука,

относится к радиусу наружного слухового прохода. Например, если скорость

звука равна 340 метров в секунду, и радиус равен 3,5 миллиметра (мм), частота среза

может быть приблизительно равна 28,4 килогерц (кГц). Любой звук с частотой ниже 28,4 кГц может передаваться в виде плоской волны в наружном слуховом проходе. В общем случае длина волны шума может быть намного больше длины наружного слухового прохода (например, 25 мм). Только в качестве примера, длина волны шума с частотой 3 кГц может быть примерно равна 113 мм, что примерно в четыре раза больше длины наружного слухового прохода. Если шум передается в виде плоской волны в одном направлении во время его передачи из местоположения в датчике субполосного шума в местоположение в выходном модуле (или его части), фазовый сдвиг во время передачи может быть маленьким (например, меньше порогового значения), и им можно пренебречь при выработке фазомодулированного сигнала

.Where

refers to the cutoff frequency of the external auditory canal,

refers to the speed of sound,

refers to the radius of the external auditory meatus. For example, if the speed

sound is 340 meters per second, and the radius is 3.5 millimeters (mm), cutoff frequency

may be approximately equal to 28.4 kilohertz (kHz). Any sound below 28.4 kHz can be transmitted as a plane wave in the external auditory canal. In general, the wavelength of the noise can be much longer than the length of the external auditory canal (for example, 25 mm). By way of example only, the wavelength of noise at 3 kHz may be approximately 113 mm, which is approximately four times the length of the external auditory canal. If the noise is transmitted as a plane wave in one direction during its transmission from a location in the subband noise sensor to a location in the output module (or part thereof), the phase shift during transmission may be small (e.g., less than a threshold) and may be neglect when generating a phase-modulated signal

.

и выработки сигнала

коррекции путем модуляции амплитуды фазомодулированного сигнала

. В некоторых вариантах осуществления амплитуда шума может ослабляться во время его передачи из местоположения в датчике субполосного шума в местоположение в модуле вывода (или его части). Коэффициент

ослабления амплитуды может быть определен для измерения ослабления амплитуды шума во время передачи. Коэффициент

ослабления амплитуды может ассоциироваться с одним или несколькими факторами, включая, например, материал и/или конструкцию компонента акустического канала, по которому передается шум, местоположение датчика субполосного шума относительно модуля вывода (или его части) или тому подобное, или любое их сочетание. В некоторых вариантах осуществления коэффициент

ослабления амплитуды может представлять собой параметр настройки по умолчанию системы 100A шумоподавления (или 100B) или может быть предварительно определен в ходе реального или смоделированного эксперимента. Только в качестве примера, коэффициент

ослабления амплитуды может быть определен путем сравнения амплитуды аудиосигнала вблизи датчика субполосного шума (например, до того, как он поступит в аудиовещательное устройство) и амплитуды аудиосигнала после его передачи в местоположение в модуле вывода. В некоторых альтернативных вариантах осуществления ослабление амплитуды шума можно не учитывать, например, если ослабление амплитуды во время передачи шума меньше порогового значения, и/или коэффициент

ослабления амплитуды по существу равен 1. В таких случаях фазомодулированный сигнал

может быть обозначен как сигнал коррекции субполосного шума сигнала

субполосного шума.Amplitude modulator 720 may be configured to receive a phase modulated signal

and signal generation

correction by modulating the amplitude of the phase-modulated signal

. In some embodiments, the amplitude of the noise may be attenuated during its transmission from a location in the subband noise sensor to a location in the output module (or part thereof). Coefficient

amplitude attenuation can be determined to measure the amplitude attenuation of the noise during transmission. Coefficient

amplitude attenuation may be associated with one or more factors, including, for example, the material and/or design of the acoustic channel component carrying the noise, the location of the subband noise sensor relative to the output module (or part thereof), or the like, or any combination thereof. In some embodiments, the coefficient

The amplitude attenuation may be a default setting of the squelch system 100A (or 100B) or may be predetermined during a real or simulated experiment. By way of example only, the coefficient

Amplitude attenuation can be determined by comparing the amplitude of the audio signal in the vicinity of the subband noise sensor (eg, before it enters the audio broadcast device) and the amplitude of the audio signal after it has been transmitted to a location in the output module. In some alternative embodiments, the noise amplitude attenuation may be ignored, for example, if the amplitude attenuation during noise transmission is less than a threshold, and/or the factor

amplitude attenuation is essentially equal to 1. In such cases, the phase-modulated signal

can be denoted as a signal subband noise correction signal

subband noise.

в соответствии с уравнением (6), как показано ниже:In some embodiments, the implementation of the noise reduction device (for example, the noise reduction device 200, the noise reduction device 300) may include a plurality of subband noise reduction modules 230. Each of the subband noise canceling modules 230 may be of the same design as the subband noise canceling module 700 as shown in FIG. 7 and can be configured to generate a corresponding subband noise correction signal. Multiple subband noise correction signals can be combined into one noise correction signal

according to Equation (6) as shown below:

. Уравнение (6)

. Equation (6)

субполосного шума, принимая во внимание сдвиг фазы сигнала субполосного шума

во время передачи сигнала.FIG. 9 is a schematic diagram illustrating an exemplary subband noise reduction module 900 according to some embodiments of the present disclosure. Subband squelch module 900 may be an exemplary embodiment of subband squelch module 230-i as described with reference to FIGS. noise reduction can be configured to modulate the phase of the signal

subband noise, taking into account the phase shift of the subband noise signal

during signal transmission.

может иметь фазовый сдвиг

во время его передачи из местоположения в датчике субполосного шума (например, датчике 220 субполосного шума) в местоположение в модуле вывода (например, модуле 170 вывода) или его части (например, в блоке вывода). Фазовый сдвиг

можно определить в соответствии с уравнением (7), как показано ниже:By way of example only, the phase of the subband noise signal

may have a phase shift

during its transmission from a location in a subband noise sensor (eg, subband noise sensor 220) to a location in an output module (eg, output module 170) or a portion thereof (eg, in an output unit). Phase shift

can be determined according to Equation (7) as shown below:

, Уравнение (7)

, Equation (7)

может относиться к центральной частоте сигнала

субполосного шума, и

может относиться к скорости распространения звука. Взяв в качестве примера устройство 200 шумоподавления, шум 210, подлежащий уменьшению, может быть получен из источника звука. Если шум 210 является сигналом ближнего поля,

может относиться к разности между расстоянием от источника звука до датчика 220 субполосного шума и расстоянием от источника звука до модуля 170 вывода (или его блока вывода). Если шум 210 является сигналом дальнего поля,

может быть равен

, где

может относиться к расстоянию между датчиком 220 субполосного шума и модулем 170 вывода (или его блоком вывода), и

относится к углу между акустическим источником и датчиком 220 субполосного шума или модулем 170 вывода (или его устройство вывода). Согласно уравнению (6), фазовый сдвиг

может увеличиваться с увеличением

и с увеличением

.Where

can refer to the center frequency of the signal

subband noise, and

may refer to the speed of sound. Taking the noise canceling device 200 as an example, the noise 210 to be reduced can be obtained from a sound source. If noise 210 is a near field signal,

may refer to the difference between the distance from the sound source to the subband noise sensor 220 and the distance from the sound source to the output module 170 (or its output unit). If noise 210 is a far field signal,

may be equal

, Where

may refer to the distance between the subband noise sensor 220 and the output module 170 (or its output unit), and

refers to the angle between the acoustic source and the subband noise sensor 220 or output module 170 (or its output device). According to equation (6), the phase shift

may increase with increasing

and with an increase

.

, фазовый модулятор 710 может выполнять инверсию фазы, а также фазовую компенсацию сигнала

субполосного шума для выработки фазомодулированного сигнала. В некоторых вариантах осуществления фазовый модулятор 710 может включать в себя всепропускающий фильтр. Функция всепропускающего фильтра может быть обозначена как

, где

относится к угловой частоте. В идеальной ситуации амплитудная характеристика

| всепропускающего фильтра может быть равна 1, и фазовая характеристика всепропускающего фильтра может быть равна фазовому сдвигу

. Всепропускающий фильтр может задерживать сигнал

субполосного шума с временной задержкой

для выполнения фазовой компенсации,

можно определить в соответствии с уравнением (8), как показано ниже:To compensate for the phase shift

, the phase modulator 710 can perform phase inversion as well as phase compensation of the signal

subband noise to generate a phase modulated signal. In some embodiments, phase modulator 710 may include an all-pass filter. The function of an all-pass filter can be denoted as

, Where

refers to the angular frequency. In an ideal situation, the amplitude characteristic

| of the all-pass filter may be equal to 1, and the phase response of the all-pass filter may be equal to the phase shift

. An all-pass filter can delay the signal

subband noise with time delay

to perform phase compensation,

can be determined according to Equation (8) as shown below:

. Уравнение (8)

. Equation (8)

субполосного шума для выработки фазомодулированного сигнала

, как показано на фиг.9. Амплитудный модулятор 720 может дополнительно модулировать амплитуду фазомодулированного сигнала

на основе коэффициента

ослабления амплитуды, как описано на фиг.7, чтобы выработать сигнал коррекции субполосного шума (то есть

) для уменьшения сигнала 10 субполосного шума

.In such cases, the phase modulator 710 can perform phase inversion and signal phase compensation.

subband noise to generate a phase modulated signal

, as shown in Fig.9. Amplitude modulator 720 can further modulate the amplitude of the phase modulated signal

based on the ratio

amplitude attenuation as described in FIG. 7 to generate a subband noise correction signal (i.e.

) to reduce signal 10 subband noise

.

коррекции шума в соответствии с уравнением (9), как показано ниже:In some embodiments, the implementation of the noise reduction device may include many modules 230 subband noise reduction. Each of the subband noise canceling modules 230 may be of the same or similar design as the subband noise canceling module 900 as shown in FIG. 9 and may be configured to generate a corresponding subband noise correction signal. Multiple subband noise correction signals can be combined into one signal

noise correction according to Equation (9) as shown below:

. Уравнение (9)

. Equation (9)

It should be noted that the above description of Figures 7 and 9 is intended to be illustrative and not to limit the scope of the present disclosure. Many alternatives, modifications and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to provide additional and/or alternative exemplary embodiments. For example, modules 700 and/or 900 subband noise reduction may include one or more additional components. Additionally or alternatively, one or more components of the subband noise reduction modules 700 and/or 900, such as the amplitude modulator 702 described above, may be omitted.

могут передаваться в амплитудный модулятор 720 для амплитудной модуляции, и затем передаваться в фазовый модулятор 710 для фазовой модуляции. Например, амплитудный модулятор 720 может выработать амплитудно-модулированный сигнал на основе коэффициента

и ослабления амплитуды и выработать соответствующий сигнал коррекции субполосного шума путем выполнения фазовой модуляции (например, инверсии фазы и при необходимости фазовую компенсации) над амплитудно-модулированным сигналом.In some alternative embodiments, the subband noise signals

may be transmitted to an amplitude modulator 720 for amplitude modulation, and then transmitted to a phase modulator 710 for phase modulation. For example, amplitude modulator 720 may generate an amplitude modulated signal based on a gain

and amplitude attenuation and generate an appropriate subband noise correction signal by performing phase modulation (eg, phase inversion and, if necessary, phase compensation) on the amplitude modulated signal.

FIG. 10 is a schematic diagram illustrating an exemplary subband noise sensor 220C according to some embodiments of the present disclosure. Subband noise sensor 220C may be an exemplary subband noise sensor 220A as described with reference to FIG. Subband noise suppression modules (eg, subband noise suppression modules 230) may be integrated into subband noise sensor 220C such that subband noise sensor 220C can perform the functions of both subband noise sensor 220A and subband suppression modules. In other words, subband noise sensor 220C may be configured to detect noise 210 to generate a plurality of subband noise signals and a plurality of subband noise correction signals for correcting the subband noise signals.

As shown in FIG. 10, the subband noise sensor 220C may include an acoustic-electric transducer 410 and a band splitter 1010. Similar to the band splitter 420 described with reference to FIG. 4, the band splitter 1010 may include a plurality of bandpass filters, each of which may bandpass the electrical signal generated by the acoustic-to-electric converter 410 to generate a plurality of subband noise signals. Each bandpass filter may further include a digital signal processor that may implement the function of a subband noise reduction module (eg, subband noise reduction module 700 or 900 as described with reference to FIGS. 7 and 9). By way of example only, a digital signal processor may phase modulate and/or amplitude modulate the subband noise signal to generate a corresponding subband noise correction signal. Thus, the subband noise canceling modules can be omitted from the noise canceling device, which makes it possible to simplify the structure of the noise canceling device.

It should be noted that the above description of the subband noise sensor 220C is intended to be illustrative and not to limit the scope of the present disclosure. Many alternatives, modifications and variations will be apparent to those skilled in the art. Features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to provide additional and/or alternative exemplary embodiments. For example, subband noise sensor 220C may include one or more additional components. Additionally or alternatively, one or more components of the subband noise sensor 220C described above may be omitted. In some embodiments, the band splitter 1010 may generate a subband noise correction signal without performing amplitude modulation.

FIG. 11 is a schematic diagram illustrating an exemplary noise reduction system 1100 according to some embodiments of the present disclosure. The noise reduction system 1100 may be an exemplary embodiment of the noise reduction system 100A as described with reference to FIG. 1A. As shown in FIG. 11, the noise canceling system 1100 may include an environmental noise reducer 120A, a residual noise reducer 150A, an integrated module 1120, and an output module 170. The environmental noise reduction device 120A and the residual noise reduction device 150A may be exemplary embodiments of the environmental noise reduction device 120 and the residual noise reduction device 150, respectively.

The environmental noise reduction device 120A may be configured to reduce the environmental noise 110 using a subband noise reduction technique. As shown in FIG. 11, the environmental noise reduction device 120A may have a similar structure to the noise reduction device 200 as described with reference to FIG. The environmental noise reduction device 120A may include a subband noise sensor 220, a plurality of subband noise suppression modules 230, and a combined module 240. The subband noise sensor 220 may detect environmental noise 110 and generate a plurality of subband environmental noise signals (e.g., A1 signals). -Am subband environmental noise). The sub-band environmental noise signal generated in response to ambient noise 110 may be similar to the sub-band noise signal generated in response to noise 210, as described with reference to FIG.

The subband noise canceling modules 230 may generate a plurality of subband environmental noise correction signals (eg, subband environmental noise correction signals A1'-Am'), each of which is used to reduce one of the subband environmental noise signals. The subband environmental noise correction signal for reducing the subband environmental noise signal may be similar to the subband noise correction signal for reducing the subband noise signal, as described with reference to FIG. The combiner 240 may combine the subband environmental noise correction signals to generate an environmental noise correction signal 130 and transmit the environmental noise correction signal 130 to the combiner 1120 .

The residual noise reduction device 150A may be configured to reduce the residual noise 140 using full band noise reduction technology. The residual noise reduction device 150A may include a residual noise sensor 1130 and a residual noise reduction module 1110. Residual noise sensor 1130 may be configured to detect residual noise 140 and generate a residual noise signal in response to detected residual noise 140. For example, residual noise sensor 1130 may include one acoustic-electric transducer that generates a residual noise signal having or substantially the same) bandwidth as the residual noise 140. In some embodiments, the implementation of the sensor 1130 residual noise may be installed next to the module 170 output or inside it. For example, the residual noise sensor 1130 may be installed in the output module 170 adjacent to the acoustic channel from which the audio signal is generated to reduce environmental noise 110. The residual noise cancellation module 1110 may be configured to receive a residual noise signal from the residual noise sensor 1130 and generate a residual noise correction signal 160 to reduce the residual noise 140. The residual noise correction signal 160 may be transmitted from the residual noise reduction module 1110 to the combining module 1120.

In some alternative embodiments, residual noise reduction device 150A may use residual noise reduction technology to reduce residual noise 140. By way of example only, residual noise reduction device 150A may have a similar design to residual noise reduction device 200, as described with reference to in Fig.2. The residual noise sensor 1130 and the residual noise reduction module 1110 may have functions similar to those of the subband noise sensor 220 and subband noise reduction modules 230, respectively. The residual noise signal generated by the residual noise sensor 1130 may include a plurality of residual subband noise signals, each of which may have a narrower bandwidth than the residual noise 140. The residual noise correction signal 160 produced by the residual noise reduction module 1110 may include a plurality of residual subband noise correction signals to reduce the residual subband noise signals, or be a combined signal of the residual subband noise correction signals.

The combiner 1120 may be configured to combine the environmental noise correction signal 130 and the residual noise correction signal 160 to produce a combined signal that may be passed to the output module 170 for output. In some embodiments, the combined signal generated by combiner 1120 may be a digital signal, and output module 170 may convert the combined signal to an audio signal for output.

FIG. 12 is a schematic diagram illustrating an exemplary noise reduction system 1200 according to some embodiments of the present disclosure. The noise reduction system 1200 may be an exemplary embodiment of the noise reduction system 100B as described with reference to FIG. 1B. The noise reduction system 1200 may be similar to the noise reduction system 1100 described with reference to FIG. 11, except for some components or functions. Compared with the noise reduction system 1100, the noise reduction system 1200 may further include a digital-to-analog converter 1210, a digital-to-analog converter 1230, and an output module 180. The environmental noise correction signal 130 produced by the environmental noise reduction apparatus 120A and the residual noise correction signal 160 produced by the residual noise reduction apparatus 150A can be processed and output, respectively, without combining.

In some embodiments, the environmental noise correction signal 130 and the residual noise correction signal 160 may be digital signals. D/A converters 1210 and 1230 may be configured to convert the environmental noise correction signal 130 and the residual noise correction signal 160 into analog signals 1220 and 1240, respectively. The analog signal 1220 may further be transmitted from the digital-to-analog converter 1210 to the output module 170 for output. The analog signal 1240 may further be transmitted from the digital-to-analog converter 1230 to the output module 180 for output.

FIG. 13 is a schematic diagram illustrating an exemplary noise reduction system 1300 according to some embodiments of the present disclosure. The noise reduction system 1300 may be similar to the noise reduction system 1100 described with reference to FIG. 11, except for some components or functions. As shown in FIG. 13, the noise canceling system 1300 may include an environmental noise reducer 120A, a residual noise reducer 150B, and an output unit 170. The environmental noise correction signal 130 generated by the environmental noise reduction device 120A can be output by the output unit 170 .

) фазового модулятора и/или коэффициента ослабления амплитуды (например,

) амплитудного модулятора таким образом, чтобы не было или по существу не было остаточного шума после подавления окружающего шума 110 сигналом 130 коррекции окружающего шума. Таким образом, модуль 230 субполосного шумоподавления может осуществлять автоматическую регулировку в соответствии с остаточным шумом 140, что повышает точность и стабильность системы шумоподавления 1300.The residual noise reduction device 150B may include a residual noise sensor 1130 and a feedback module 1310. The feedback module 1310 may be configured to adjust the subband cancellers 230 in response to the residual noise 140 in order to cancel the residual noise 140. For example, the adjuster may instruct one or more subband cancellers 230 to adjust one or more parameters of modules 230 subband noise reduction. By way of example only, as described elsewhere in this disclosure (e.g., see FIGS. 7-9 and its corresponding description), subband noise reduction module 230 may include a phase modulator (e.g., phase modulator 710) and/or an amplitude modulator. (eg, amplitude modulator 720). The feedback module 1310 may send a command to the subband noise reduction module 230 to adjust the time delay (for example,

) phase modulator and/or amplitude attenuation factor (for example,

) amplitude modulator such that there is no or substantially no residual noise after ambient noise cancellation 110 by ambient noise correction signal 130. Thus, the subband noise canceling module 230 can automatically adjust according to the residual noise 140, which improves the accuracy and stability of the noise canceling system 1300.

It should be noted that the above description is for illustrative purposes only and is not intended to limit the scope of the present disclosure. Numerous changes and modifications can be made by those skilled in the art in accordance with the teachings of this disclosure. However, these variations and modifications should not go beyond the scope of this disclosure. The noise reduction system (eg, any of the noise reduction systems 1100, 1200, and 1300) may include one or more additional components, and/or one or more components of the noise reduction system may be omitted. By way of example only, the digital-to-analogue converter 1210 may be omitted from the noise reduction system 1200 or integrated into the output module 170. The environmental noise correction signals in the frequency band may be transmitted to a plurality of output blocks of the output module 170 for output.

FIG. 14 is a schematic diagram illustrating an exemplary residual noise reduction apparatus 150C according to some embodiments of the present disclosure. Residual noise reducer 150C may be an exemplary embodiment of residual noise reducer 150 that may be used to reduce residual noise 140 using subband noise reduction technology.

As shown in FIG. 14, the residual noise reduction device 150C may have a structure similar to the noise canceling device 200 as described with reference to FIG. The residual noise reduction apparatus 150C may include a subband noise sensor 220, a plurality of subband noise cancellation modules 230, and a combined module 240. The subband noise sensor 220 may be installed adjacent to the output module 170 to detect residual noise 140 and generate a plurality of residual subband noise signals. (eg, residual subband noise signals R1-Rk). The subband noise canceling modules 230 may generate a plurality of residual subband noise correction signals (eg, residual subband noise correction signals R'1-R'k) that are designed to reduce one of the subband residual noise signals. The combiner 240 may combine the residual subband noise correction signals to generate a residual noise correction signal 160 . The residual noise correction signal 160 may be further transmitted to the output module 170 for output.

In some embodiments, the subband noise cancellation module 230-i may include a phase modulator (eg, a phase inverter) configured to perform a phase inversion on the corresponding residual subband noise signal Ri. Since the subband noise sensor 220 for detecting the residual noise 140 can be installed near the output module 170, the subband noise canceling module 230-i can generate an appropriate residual subband noise correction signal Ri' without performing phase compensation and/or amplitude modulation of the residual subband noise signal Ri .

FIG. 15 is a schematic diagram illustrating an exemplary noise reduction system 1500 according to some embodiments of the present disclosure. The noise reduction system 1500 may be similar to the noise reduction system 1100 described with reference to FIG. 11, except that the noise reduction system 1500 may combine analog signal processing technology to reduce noise. As shown in FIG. 15, the noise canceling system 1500 may include an environmental noise reducer 120B, a residual noise reducer 150D, an integrated module 1505, and an output module 170. As shown in FIG.

The environmental noise reduction apparatus 120B may include a subband noise sensor (not shown in FIG. 15), a plurality of analog signal processing components 1501 (e.g., analog signal processing components 1501-1 to 1501-m), and a combined sensor module 1504. subband noise reduction device 120B can detect the environmental noise 110 and generate subband environmental noise signals (eg, subband environmental noise signals N1-Nm). The subband environmental noise signals generated by the subband noise sensor of the ambient noise reduction apparatus 120B may be analog signals.

The analog signal processing components 1501 may have a function similar to the subband noise canceling modules 230 of the ambient noise reduction device 120A, as described with reference to FIG. For example, the analog signal processing components 1501 may receive subband environmental noise signals and generate a plurality of subband environmental noise correction signals (eg, environmental subband noise correction signals N1'-Nm'). The environmental subband noise correction signals generated by the analog signal processing components 1501 may be analog signals. The subband environmental noise correction signals may be combined by combiner 1504 into an environmental noise correction signal 130', which may be an analog signal to reduce environmental noise.

In some embodiments, the analog signal processing component 1501-i may include one or more first analog circuit components for performing phase modulation of the ambient subband noise signal Ni. Phase modulation by one or more of the first analog circuit components may be performed in a manner similar to that performed by a phase modulator (eg, phase modulator 710) as described elsewhere in this disclosure (eg, see FIGS. 7-9 and its corresponding description). ). For example, one or more of the first analog circuit components may include an amplifier (eg, an inverting amplifier) that is used to perform phase inversion of the ambient subband noise signal Ni. Additionally or alternatively, one or more of the first analog circuit components may include an analog delay line (e.g., inductor-capacitor (LC) circuit delay line, active analog delay line) that is used to perform phase offset compensation of the sub-band environmental noise signal Ni .

The residual noise reduction device 150D may include a residual noise sensor 1503 and an analog signal processing component 1502. The residual noise sensor 1503 can detect the residual noise 140 and generate a residual noise signal as an analog signal. The analog signal processing component 1502 may be configured to generate a residual noise correction signal 160', which may be an analog signal for reducing residual noise 140. The combiner 1505 may be configured to combine the environmental noise correction signal 130' and the correction signal 160' residual noise to produce the combined analog signal. The combined analog signal may be output by the output module 170 .

Using analog signal processing components, the noise reduction system 1500 can reduce ambient noise and residual noise 140 without a sampler (eg, samplers 620), a digital-to-analog converter (eg, digital-to-analog converters 1210 and 1230), an analog-to-digital converter, and the like, thereby simplifying the noise reduction system 1500 and improving the operation speed of the noise reduction system 1500.

Thus, after describing the basic concepts to those skilled in the art upon reading this detailed disclosure, it will be apparent that the previous detailed disclosure is intended to be presented by way of example only and is not limiting. There are various changes, improvements and modifications intended for those skilled in the art, although this is not expressly stated in this document. These changes, improvements, and modifications are intended to be provided in the present disclosure and are within the spirit and scope of the exemplary embodiments of the present disclosure.

Moreover, certain terminology has been used to describe embodiments of the present disclosure. For example, the terms "one embodiment," "an embodiment," and/or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Thus, it should be emphasized that two or more references to "an embodiment" or "one embodiment" or "alternative embodiment" in various parts of this specification do not necessarily refer entirely to the same embodiment. In addition, specific features, structures, or characteristics may be combined in accordance with one or more embodiments of the present disclosure.

In addition, those skilled in the art will appreciate that aspects of the present disclosure may be illustrated and described herein in any of a number of patentable classes or contexts, including any new and useful process, machine, manufacture, or composition of matter, or any new and useful their improvement. Accordingly, aspects of the present disclosure may be implemented entirely in hardware, entirely in software (including firmware, resident software, microcode, etc.), or a combination of software and hardware implementations that are generally may be referred to herein as a "unit", "module", or "system". In addition, aspects of the present disclosure may take the form of a computer program product embodied on one or more computer-readable storage media having a computer-readable program embodied thereon.

The computer-readable signal carrier may include a propagating data signal with computer-readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagating signal may take any of a variety of forms, including electromagnetic, optical, and the like. or any suitable combination thereof. A computer-readable medium can be any computer-readable medium that is not a computer-readable medium and that can transmit, distribute, or transport a program for use by or in connection with a system, hardware device, or instruction execution device. The program code embodied on a computer-readable medium may be transmitted using any suitable medium, including wireless communication, wired communication, fiber optic cable, RF, and the like. or any suitable combination thereof.

Computer program code for performing operations for aspects of this disclosure may be written in any combination of one or more programming languages, including an object-oriented programming language such as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C# .VB. NET, Python, etc., traditional procedural programming languages such as the "C" programming language, Visual Basic, Fortran 2003, Perl, COBOL 2002, PHP, ABAP, dynamic programming languages such as Python, Ruby, and Groovy, or other programming languages. The program code may run entirely on the user's computer, partially on the user's computer as a separate software package, partially on the user's computer, and partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or wide area network (WAN), or the connection may be made to an external computer (for example, via the Internet using an Internet Service Provider) or cloud computing environment, or offered as a service such as software as a service (SaaS).

Furthermore, the order of processing elements or sequences given, or the use of numbers, letters, or other designations, is thus not intended to limit the claimed processes and methods in any order other than that which may be indicated in the claims. While the above disclosure discusses what is now considered to be a variety of useful embodiments of the disclosure through various examples, it should be noted that such details are for that purpose only and that the appended claims are not limited to the disclosed embodiments, but rather are intended to covering modifications and arrangements that are within the spirit and scope of the disclosed embodiments. For example, while the implementation of the various components described above may be implemented in a hardware device, it may also be implemented as a pure software solution, such as installation on an existing server or mobile device.

Similarly, it should be noted that in the above description of embodiments of the present disclosure, various features are sometimes grouped together in one embodiment, figure, or description thereof to streamline the disclosure and aid in understanding one or more of the various embodiments of the disclosure. However, this manner of disclosure should not be interpreted as reflecting the intent that the claimed subject matter requires more features than are expressly stated in each claim. Rather, the claimed subject matter may not comprise all of the features of one of the foregoing disclosed embodiments.

Claims (34)

1. A noise reduction system, comprising: a subband noise sensor configured to detect noise and generate a plurality of subband noise signals in response to the detected noise, each of the subband noise signals having a different subband from the other noise band, the noise including environmental noise; a plurality of subband noise canceling modules, each of the subband noise canceling modules being configured to receive one of the subband noise signals from the subband noise sensor and generate a subband noise correction signal to reduce the received subband noise signal; an output module, configured to receive subband noise correction signals and output a noise correction signal for noise reduction based on the subband noise correction signals; a residual noise sensor configured to detect residual noise and generate a residual noise signal in response to the detected residual noise, wherein the distance between the residual noise sensor and the output module is smaller than the distance between the subband noise sensor and the output module; And a residual noise reduction module, configured to receive the residual noise signal and generate a residual noise correction signal to reduce the residual noise. 2. The system of claim 1, wherein the subband noise sensor comprises: an acoustoelectric transducer configured to detect the noise and convert the noise into an electrical signal; And a band separation module connected to the acoustoelectric converter and configured to separate the electrical signal into subband noise signals, wherein the band splitter comprises a plurality of bandpass filters, each of the bandpass filters having a unique frequency response and configured to generate one of the subband noise signals. 3. The system according to claim 2, in which: the first bandpass filter of the bandpass filters has a first frequency response and is configured to generate a first subband noise signal from the subband noise signals, the second bandpass filter of the bandpass filters has a second frequency response and is configured to generate a second subband noise signal from the subband noise signals, wherein the second subband noise signal is adjacent to the first subband noise signal among the subband noise signals in the frequency domain, wherein the first frequency response and the second frequency response intersect at a frequency point that is adjacent to at least one of the first frequency response half power point or the second frequency response half power point. 4. The system of claim 1, wherein the subband noise sensor comprises: a plurality of acoustoelectric transducers, each having a unique frequency response and configured to generate an electrical subband noise signal by noise processing; And a plurality of sampling modules, each of the sampling modules being configured to receive one electrical subband noise signal from the electrical subband noise signals and sample the received electrical subband noise signal to generate one subband noise signal from the electrical subband noise signals. 5. The system according to claim 4, in which: the first acoustoelectric transducer of the acoustoelectric transducers has a first frequency response and is configured to generate an electrical subband noise signal corresponding to the first subband noise signal from the subband noise signals, the second acoustoelectric transducer of the acoustoelectric transducers has a second frequency response and is configured to generate an electrical subband noise signal corresponding to the second subband noise signal from the subband noise signals, wherein the second subband noise signal is adjacent to the first subband noise signal among the subband noise signals in the frequency domain, wherein the first frequency response and the second frequency response intersect at a frequency point that is adjacent to at least one of the first frequency response half power point or the second frequency response half power point. 6. The system of claim 5, wherein at least one subband noise reduction module of the subband noise reduction modules comprises: a phase modulator configured to receive a corresponding subband noise signal and generate a phase modulated signal by modulating the phase of the corresponding subband noise signal; And an amplitude modulator configured to receive a phase modulated signal from the phase modulator and generate a subband noise correction signal to reduce the corresponding subband noise signal by modulating the amplitude of the phase modulated signal. 7. The system of claim 6, wherein the phase modulation of the corresponding subband noise signal includes phase inversion of the corresponding subband noise signal, and phase modulating the respective subband noise signal further includes compensating for a phase offset of the respective subband noise signal as it is transmitted from the subband noise sensor to the phase modulator. 8. The system according to any one of paragraphs. 1-7, in which: the residual noise signal generated by the residual noise sensor includes a plurality of residual subband noise signals, and the residual noise correction signal includes a plurality of residual subband noise correction signals, each of the residual subband noise correction signals being configured to reduce one of the residual subband noise signals. 9. The system according to any one of paragraphs. 1-8, additionally containing: a feedback module configured to adjust the subband noise reduction modules in accordance with the residual noise. 10. The system according to any one of claims 1-9, in which the output module includes: a signal processing unit configured to process the noise correction signal; And an electro-acoustic transducer configured to convert the processed noise correction signal into an audio signal and output the audio signal.

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