CN112086101A - Noise reduction circuit, voice recognition module and electronic equipment - Google Patents
Noise reduction circuit, voice recognition module and electronic equipment Download PDFInfo
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- G10L21/00—Speech or voice signal processing techniques to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
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Abstract
The application relates to a noise reduction circuit, a voice recognition module and electronic equipment. The noise reduction circuit includes: the main differential driving module is connected with the main sound pickup equipment and used for driving the main sound pickup equipment to work so that the main sound pickup equipment converts the collected voice signals into voice differential signals; the main differential-to-single-ended module is connected with the main differential driving module and used for converting the voice differential signal into a voice single-ended signal; the auxiliary differential driving module is connected with the auxiliary sound pickup equipment and used for driving the auxiliary sound pickup equipment to work so that the auxiliary sound pickup equipment converts the collected environmental sound signals into environmental differential signals; the auxiliary differential-to-single-ended module is connected with the auxiliary differential driving module and used for converting the environment differential signal into an environment single-ended signal; and the denoising module is respectively connected with the main differential to single-ended conversion module and the auxiliary differential to single-ended conversion module and is used for filtering the environment single-ended signal from the voice single-ended signal. The noise reduction circuit provided by the application has strong anti-interference performance.
Description
Technical Field
The present application relates to the field of electronic circuit technology, and in particular, to a noise reduction circuit, a voice recognition module, and an electronic device.
Background
With the development of technology, speech recognition is increasingly applied to electronic devices. In the speech recognition process, the sound of the surrounding environment can cause the collected speech to be doped with a large amount of background noise, and if noise reduction processing is not carried out, the noise is filtered, so that the success rate of the speech recognition is greatly reduced.
In the conventional technology, noise reduction processing is mainly performed by a software algorithm. Firstly, establishing a data model of background noise, then comparing the voice signal with the background noise model, if the voice signal is similar to the background noise model, judging the voice signal as noise, and filtering the noise signal through a software algorithm.
However, this method is easily affected by the electromagnetic interference of the circuit board itself, and has a problem of poor interference resistance.
Disclosure of Invention
Therefore, it is necessary to provide a noise reduction circuit, a voice recognition module and an electronic device for solving the problem of poor anti-interference capability.
A noise reduction circuit, comprising:
the main differential driving module is connected with the main sound pickup equipment and used for driving the main sound pickup equipment to work so that the main sound pickup equipment converts collected voice signals into voice differential signals;
the main differential-to-single-ended module is connected with the main differential driving module and used for converting the voice differential signal into a voice single-ended signal;
the auxiliary differential driving module is connected with the auxiliary sound pickup equipment and used for driving the auxiliary sound pickup equipment to work so that the auxiliary sound pickup equipment converts the collected environmental sound signals into environmental differential signals;
the auxiliary differential-to-single-ended module is connected with the auxiliary differential driving module and used for converting the environment differential signal into an environment single-ended signal;
and the denoising module is respectively connected with the main differential to single-ended conversion module and the auxiliary differential to single-ended conversion module and is used for filtering the environment single-ended signal from the voice single-ended signal.
In one embodiment, the method further comprises the following steps:
the echo differential-to-single-ended module is connected with the audio output unit and used for receiving the echo differential signal output by the audio output unit and converting the echo differential signal into an echo single-ended signal;
the echo differential-to-single-ended module is connected with the denoising module, and the denoising module is further used for filtering the echo single-ended signal from the voice single-ended signal.
In one embodiment, the method further comprises the following steps:
the main low-pass filtering module is connected with the main differential-to-single-ended module and the denoising module, and is used for filtering high-frequency noise signals in the voice single-ended signals;
the auxiliary low-pass filtering module is connected with the auxiliary differential to single-ended conversion module and the denoising module, and is used for filtering high-frequency noise signals in the environment single-ended signals;
and the echo low-pass filtering module is connected with the echo differential-to-single-ended module and the denoising module, and is used for filtering high-frequency noise signals in the echo single-ended signals.
In one embodiment, the method further comprises the following steps:
the main high-pass filtering module is connected with the main differential-to-single-ended module and the denoising module, and is used for filtering low-frequency noise signals in the voice single-ended signals;
the auxiliary high-pass filtering module is connected with the auxiliary differential to single-ended conversion module and is connected with the denoising module, and the auxiliary high-pass filtering module is used for filtering low-frequency noise signals in the environment single-ended signals;
and the echo high-pass filtering module is connected with the echo differential-to-single-ended module and the denoising module, and is used for filtering low-frequency noise signals in the echo single-ended signals.
In one embodiment, the denoising module comprises:
the same-direction input end of the operational amplification unit is connected with the main differential-to-single-ended module, and the reverse input end of the operational amplification unit is respectively connected with the auxiliary differential-to-single-ended module and the echo differential-to-single-ended module;
the homodromous filtering unit is connected with the homodromous input end of the operational amplification unit and is used for filtering noise signals at the homodromous input end of the operational amplification unit;
and the reverse filtering unit is connected with the reverse input end of the operational amplification unit and is used for filtering noise signals at the reverse input end of the operational amplification unit.
In one embodiment, the operational amplification unit includes:
an operational amplifier U4, wherein the same-direction input end of the operational amplifier U4 is connected with the same-direction filtering unit, and the reverse input end of the operational amplifier U4 is connected with the reverse filtering unit;
one end of the resistor R14 is connected with the main differential-to-single-ended module, and the other end of the resistor R14 is connected with the equidirectional input end of the operational amplifier U4;
one end of the resistor R16 is connected with the auxiliary differential-to-single-ended module, and the other end of the resistor R16 is connected with the inverting input end of the operational amplifier U4;
one end of the resistor R21 and one end of the resistor R21 are connected with the echo differential-to-single-ended module, and the other end of the resistor R21 is connected with the reverse input end of the operational amplifier U4.
In one embodiment, the main differential-to-single-ended module includes:
one end of the resistor R4 is connected with the positive electrode output end of the main differential drive module;
one end of the resistor R5 is connected with the negative electrode output end of the main differential drive module;
the same-direction input end of the operational amplifier U1 is connected with the other end of the resistor R4, the reverse-direction input end of the operational amplifier U1 is connected with the other end of the resistor R5, and the output end of the operational amplifier U1 is connected with the denoising module.
In one embodiment, the main differential-to-single-ended module further includes:
one end of the capacitor C3 is connected with the positive electrode output end of the main differential drive module, and the other end of the capacitor C3 is connected with one end of the resistor R4;
one end of the capacitor C6, one end of the capacitor C6 is connected to the negative output end of the main differential drive module, and the other end of the capacitor C6 is connected to one end of the resistor R5.
A speech recognition module comprising:
a noise reduction circuit as described above;
and the voice recognition circuit is connected with the denoising module.
An electronic device comprises the voice recognition module.
In the noise reduction circuit, the voice recognition module and the electronic device, the noise reduction circuit comprises a main differential drive module, a main differential to single-ended conversion module, an auxiliary differential drive module, an auxiliary differential to single-ended conversion module and a noise reduction module. The noise reduction is realized through the circuit, the noise of the electromagnetic interference of the circuit board of the electronic equipment can be effectively received and filtered, and the anti-interference capability is improved. Meanwhile, the driving of the main pickup equipment is realized through the main differential driving module, and the driving of the auxiliary pickup equipment is realized through the auxiliary differential driving module, so that the voice signals are not easily influenced by electromagnetic interference noise of a circuit board of the electronic equipment, the anti-interference capability is further improved, the noise reduction effect is improved, and the accuracy of voice recognition is improved. In addition, above-mentioned circuit, speech recognition module and electronic equipment of making an uproar falls adopts the circuit of making an uproar of falling of two pickup equipment, filters the ambient sound signal that vice pickup equipment gathered from the speech signal that main pickup equipment gathered, compares in the circuit of making an uproar of falling of single pickup equipment, and is more comprehensive to ambient sound's collection, discernment to the filtering is also more thorough, improves the noise reduction effect.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of a noise reduction circuit in the related art;
FIG. 2 is a schematic block diagram of another noise reduction circuit in the related art;
FIG. 3 is a schematic block diagram of a noise reduction circuit provided in one embodiment of the present application;
FIG. 4 is a schematic block diagram of a noise reduction circuit provided in another embodiment of the present application;
fig. 5 is a schematic circuit diagram of a noise reduction circuit according to an embodiment of the present application.
Detailed Description
In order to make the purpose, technical solution and advantages of the present application more clearly understood, the noise reduction circuit, the voice recognition module and the electronic device of the present application are further described in detail below by embodiments and with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings). In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present application and for simplicity in description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be considered as limiting the present application.
In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
Many electronic products are equipped with a voice recognition module. In the speech recognition process, noise may be present under the influence of the environment. Taking a vehicle-mounted electronic device as an example, such as a vehicle-mounted streaming media rearview mirror, the vehicle-mounted electronic device has a voice recognition function. However, in the vehicle-mounted environment, due to interferences such as vehicle vibration, noise of an engine, wind noise of a window and the like, a large amount of background noise is doped in the voice, and if the background noise is not filtered, the success rate of voice recognition is greatly reduced. Therefore, in order to improve the voice recognition effect, noise reduction processing may be performed on the acquired voice signal before voice recognition.
In the related art, there are several noise reduction processing techniques:
1) noise reduction is performed by software algorithms. Specifically, a background noise data model is established first, then the voice signal is compared with the background noise data model, if the voice signal and the background noise data model are similar, the voice signal is judged to be a noise signal, and the noise signal is filtered out through software.
2) A high-pass filter circuit and an operational amplifier circuit are formed by the resistor and the capacitor to filter the noise signal, as shown in fig. 1.
3) The echo of the device is filtered and cancelled by using a virtual microphone circuit, see fig. 2.
For the scheme 1), since the noise data model is fixed, while the background noise is variable and uncertain, and the background noise of different scenes is different, the scheme 1) has the problems of poor noise filtering effect and poor speech recognition effect. Meanwhile, the pre-established noise data model mainly aims at the noise in the external environment, but the circuit board of the electronic equipment can generate electromagnetic interference noise, and the noise data model cannot identify the electromagnetic interference noise and filter the noise, so the scheme 1) also has the problem of poor anti-interference capability.
With respect to scheme 2), the following problems mainly exist:
a. inability to filter strong noise
Because the scheme 2) only uses a high-pass filter circuit and only filters low-frequency noise, the scheme cannot achieve due filtering effect when external noise is strong enough (such as noise in a vehicle-mounted environment), and leaked noise, especially high-frequency noise, still enters a post-stage system.
b. Not capable of filtering echo
Scheme 2) can only filter background noise from the microphone and cannot filter echoes. Therefore, if the electronic device has its own speaker and the sound emitted by the electronic device is received by its own microphone, the sound is erroneously recognized as a voice command, which may result in an erroneous determination.
c. Poor anti-interference capability
Because the microphone circuit uses a single-end driving mode, voice signals are easily subjected to electromagnetic interference noise of an electronic equipment circuit board, and the anti-interference capability is poor.
For scheme 3), the following problems mainly exist:
a. inability to filter background noise
According to the scheme, only the echo output by the electronic equipment is filtered, and environmental noise can still be introduced to influence the accuracy of voice recognition.
b. Poor anti-interference capability
Because the microphone circuit uses a single-end driving mode, voice signals are easily subjected to electromagnetic interference noise of the electronic equipment circuit board, and the anti-interference capability is poor.
Referring to fig. 3, an embodiment of the present application provides a noise reduction circuit 10, which is used for performing noise reduction processing on a voice signal collected by a sound pickup apparatus. The sound pickup apparatus includes a main sound pickup apparatus 21 and a sub sound pickup apparatus 22, the main sound pickup apparatus 21 being configured to collect a voice signal, and the sub sound pickup apparatus 22 being configured to collect an ambient sound signal. The voice signal includes a voice command, and may further include an environmental sound signal, an echo signal, and the like. Specifically, when the main sound pickup apparatus 21 is set, the main sound pickup apparatus may be aligned with the direction of generation of the voice command to acquire a voice signal including the voice command; and the secondary pickup 22 may be positioned in a direction offset from the direction of voice command generation to capture ambient sound signals. The primary and secondary pickup devices 21 and 22 include, but are not limited to, microphones.
The noise reduction circuit 10 includes a main differential driving module 110, a main differential-to-single-ended module 120, an auxiliary differential driving module 130, an auxiliary differential-to-single-ended module 140, and a noise reduction module 150.
The input end of the main differential driving module 110 is connected to the output end of the main sound pickup device 21, and the output end of the main differential driving module 110 is connected to the input end of the main differential-to-single end conversion module 120. The output terminal of the main differential-to-single-ended module 120 is connected to a first input terminal of the denoising module 150.
The input end of the sub differential driving module 130 is connected to the output end of the sub sound pickup apparatus 22, and the output end of the sub differential driving module 130 is connected to the input end of the sub differential-to-single end conversion module 140. The output end of the sub-differential to single-ended module 140 is connected to a second input end of the denoising module 150.
The noise reduction circuit 10 operates as follows:
the main differential driving module 110 drives the main sound pickup device 21 to work, so that the main sound pickup device 21 converts the collected voice signals into signals in a differential form, and voice differential signals are obtained. The main differential driving module 110 inputs the voice differential signal to the main differential to single-ended conversion module 120, and the main differential to single-ended conversion module 120 converts the voice differential signal into a single-ended signal to obtain a voice single-ended signal. The main differential-to-single-ended module 120 inputs the voice single-ended signal to a first input terminal of the denoising module 150.
The secondary differential driving module 130 drives the secondary sound pickup apparatus 22 to operate, so that the secondary sound pickup apparatus 22 converts the collected ambient sound signal into a signal in a differential form, and obtains an ambient differential signal. The sub differential driving module 130 inputs the environment differential signal to the sub differential to single-ended module 140, and the sub differential to single-ended module 140 converts the environment differential signal into a single-ended signal to obtain an environment single-ended signal. The sub-differential to single-ended module 140 inputs the ambient single-ended signal into a second input terminal of the de-noising module 150 through the sub-differential to single-ended module 140. The denoising module 150 filters the environment single-ended signal from the voice single-ended signal, so as to achieve denoising of the voice signal. The denoising module 150 may filter the environmental single-ended signal in various forms, including but not limited to a subtraction circuit. Taking the subtraction circuit as an example, the denoising module 150 performs subtraction on the voice single-ended signal input by the first input terminal and the environment single-ended signal input by the second input terminal, and the signal output by the output terminal of the denoising module 150 is the voice single-ended signal after the environment single-ended signal is filtered out.
In this embodiment, the noise reduction circuit 10 includes a main differential driving module 110, a main differential to single-ended module 120, an auxiliary differential driving module 130, an auxiliary differential to single-ended module 140, and a noise reduction module 150. The noise reduction is realized through the circuit, the noise of the electromagnetic interference of the circuit board of the electronic equipment can be effectively received and filtered, and the anti-interference capability is improved. Meanwhile, the driving of the main sound pickup device 21 is realized through the main differential driving module 110, and the driving of the auxiliary sound pickup device 22 is realized through the auxiliary differential driving module 130, so that the voice signal is not easily influenced by the electromagnetic interference noise of the circuit board of the electronic device, the anti-interference capability is further improved, the noise reduction effect is improved, and the accuracy of voice recognition is improved. In addition, in this embodiment, the noise reduction circuit of two sound pickup apparatuses is adopted, and the ambient sound signal collected by the auxiliary sound pickup apparatus 22 is filtered from the voice signal collected by the main sound pickup apparatus 21, so that the collection and recognition of the ambient sound are more comprehensive compared with the noise reduction circuit of a single sound pickup apparatus, and thus the filtering is more thorough, and the noise reduction effect is improved.
Referring to fig. 4, in an embodiment, the noise reduction circuit 10 further includes an echo differential-to-single-ended module 160. The input terminal of the echo differential-to-single-ended module 160 is connected to the audio output unit 23 of the electronic device. The audio output unit 23 of the electronic apparatus is used to output an audio signal. The audio signal output by the audio output unit 23 is released to the environment through a speaker or the like, and is received by the sound pickup apparatus, that is, echo is formed. The audio signal output by the audio output unit 23 is a differential signal named echo differential signal.
The echo differential-to-single-ended module 160 converts the echo differential signal output by the audio output unit 23 into a single-ended signal, obtains an echo single-ended signal, and outputs the echo single-ended signal to the third input terminal of the denoising module 150. The denoising module further filters the echo single-ended signal from the voice single-ended signal, namely: the filtering module 150 filters the environment single-ended signal and the echo single-ended signal from the voice single-ended signal, so as to implement noise reduction processing and obtain a voice command.
The noise reduction circuit provided by the embodiment can not only realize the filtration of background noise, but also realize the filtration of echo, and improves the filtering effect on speech signals, thereby improving the accuracy of subsequent speech recognition.
In one embodiment, the noise reduction circuit 10 further includes a low pass filtering module and a high pass filtering module. The low-pass filtering module and the high-pass filtering module may be connected after the main differential-to-single-ended module 120, the sub differential-to-single-ended module 140, and the echo differential-to-single-ended module 160 and before the denoising module 150. The low-pass filtering module and the high-pass filtering module may also be connected after the denoising module 150, i.e., connected to the output of the denoising module 150. The low-pass filtering module is used for filtering high-frequency noise signals in the sound signals, the high-pass filtering module is used for filtering low-frequency noise signals in the sound signals, and the signal-to-noise ratio of the circuit can be improved by filtering the high-frequency noise signals and the low-frequency noise signals.
In one embodiment, the low pass filtering module includes a primary low pass filtering module 171, a secondary low pass filtering module 172, and an echo low pass filtering module 173. The high-pass filtering module includes a main high-pass filtering module 181, a sub high-pass filtering module 182, and an echo high-pass filtering module 183.
The input end of the main low-pass filter module 171 is connected to the output end of the main differential-to-single-ended module 120, and the output end of the main low-pass filter module 171 is connected to the input end of the main high-pass filter module 181. The main low-pass filtering module is used for filtering high-frequency noise signals in the voice single-ended signal. The output end of the main high-pass filtering module 181 is connected to the first input end of the denoising module 150, and the main high-pass filtering module 181 is configured to filter a low-frequency noise signal in the voice single-ended signal. The high-frequency noise signal and the low-frequency noise signal in the voice single-ended signal are filtered by the main low-pass filtering module 171 and the main high-pass filtering module 181, so that the signal-to-noise ratio of the circuit can be improved.
The input end of the sub low-pass filtering module 172 is connected to the output end of the sub differential-to-single-ended module 140, and the output end of the sub low-pass filtering module 172 is connected to the input end of the sub high-pass filtering module 182. The auxiliary low-pass filtering module is used for filtering high-frequency noise signals in the environment single-ended signal. The output end of the secondary high-pass filtering module 182 is connected to the second input end of the denoising module 150, and the secondary high-pass filtering module 182 is configured to filter a low-frequency noise signal in the environmental single-ended signal. The high-frequency noise signal and the low-frequency noise signal in the environment single-ended signal are filtered by the auxiliary low-pass filtering module 172 and the auxiliary high-pass filtering module 182, so that the signal-to-noise ratio of the circuit can be further improved.
The input end of the echo low-pass filtering module 173 is connected to the output end of the echo differential-to-single-ended module 160, and the output end of the echo low-pass filtering module 173 is connected to the output end of the echo high-frequency filtering module 183. The echo low-pass filtering module 173 is used to filter out the high-frequency noise signal in the echo single-ended signal. The output end of the echo high-pass filtering module 183 is connected to the third input end of the denoising module 150, and the echo high-pass filtering module 183 is configured to filter a low-frequency noise signal in the echo single-ended signal. The echo low-pass filtering module 173 and the echo high-pass filtering module 183 filter the high-frequency noise signal and the low-frequency noise signal in the echo single-ended signal, so that the signal-to-noise ratio of the circuit can be further improved.
It is understood that the low-pass filtering module and the high-pass filtering module may be provided separately, or may be combined and integrated with other functional modules in the noise reduction circuit 10. In one embodiment, each differential-to-single-ended module may be combined with a corresponding low-pass filtering module to form a differential-to-single-ended low-pass module. Further, the noise reduction circuit 10 may further include an amplifying module to amplify each part, and the amplifying module may also be combined and integrated with the differential-to-single-ended low-pass module to form the differential-to-single-ended low-pass amplifying module. The following is a further description with reference to the embodiments and the drawings.
Referring to fig. 5, in an embodiment, the main differential driving module 110 includes a resistor R1, a resistor R2, a resistor R7, a resistor R9, and a capacitor C4. The resistor R1 and the resistor R2 are connected in series between the positive output end of the main sound pickup device 21 and the power supply MIC _ BIAS. Resistors R7 and R9 are connected in series between the negative output terminal of the main sound pickup device 21 and ground. A capacitor C4 is connected in parallel between the positive and negative output terminals of the main sound pickup device 21. In one embodiment, the main differential driver module 110 may further include a power filter unit, wherein the power filter unit includes a capacitor C1, and the capacitor C1 is connected in series between the power supply MIC _ BIAS and the ground terminal. The capacitor C1 is used to provide clean power to the microphone.
In one embodiment, the main differential driving module 110 may further include a differential signal filtering unit. The differential signal filtering unit includes a capacitor C5, a capacitor C9, and a capacitor C10. The capacitor C5 is connected in parallel between the positive output terminal and the negative output terminal of the main sound pickup apparatus 21, the capacitor C9 is connected in series between the negative output terminal and the ground terminal of the main sound pickup apparatus 21, and the capacitor C10 is connected in series between the positive output terminal and the ground terminal of the main sound pickup apparatus 21. The capacitor C5, the capacitor C9 and the capacitor C10 are used for filtering the voice differential signal.
In one embodiment, the main differential-to-single-ended module 120 includes a resistor R4, a resistor R5, and an operational amplifier U1. The main low pass filter module 171 includes a capacitor C2, a resistor R3, a capacitor C8, and a resistor R6. One end of the resistor R4 is connected to the positive output terminal of the main differential driving module 110, and the other end of the resistor R4 is connected to the non-inverting input terminal of the operational amplifier U1. One end of the resistor R5 is connected to the negative output terminal of the main differential driving module 110, and the other end of the resistor R5 is connected to the inverting input terminal of the operational amplifier U1. The capacitor C2 and the resistor R3 are connected in parallel and then connected between the homodromous input end and the ground end of the operational amplifier U1. The capacitor C8 is connected in parallel with the resistor R6 and then connected between the inverting input terminal and the output terminal of the operational amplifier U1. An output of the operational amplifier U1 is connected to a first input of the denoising module 150. The main differential to single-ended conversion module 120 can be integrated with the main low-pass filtering module 171, which not only can realize the differential to single-ended conversion function, but also has the amplification and low-pass filtering functions, and simplifies the circuit.
In one embodiment, the main differential-to-single-ended module 120 further includes a capacitor C3 and a capacitor C6. The capacitor C3 is connected in series between the positive output terminal of the main differential driving module 110 and the resistor R4, and the capacitor C6 is connected in series between the negative output terminal of the main differential driving module 110 and the resistor R5. And the capacitor C3 and the capacitor C6 are used for isolating direct-current components, so that the sound pickup effect of the main sound pickup equipment is ensured.
In one embodiment, the main high-pass filtering module 181 includes a capacitor C7 and a resistor R8, and the capacitor C7 is connected in series between the output of the main differential-to-single-ended module 120 and the first input of the denoising module 150, i.e., between the output of the operational amplifier U1 and the first input of the denoising module 150. The resistor R8 is connected in series between the first input terminal of the denoising module 150 and the ground.
In one embodiment, the secondary differential driving module 130 may include a resistor R10, a resistor R12, a resistor R22, a resistor R23, a capacitor C16, a capacitor C11, a capacitor C17, a capacitor C21, and a capacitor C23. The connection relationship and the functions of the components of the sub differential driving module 130 refer to fig. 3 and the main differential driving module 110, which are not described herein again. The sub-differential to single-ended module 140 may include a capacitor C14, a capacitor C18, a resistor R15, a resistor R18, and an operational amplifier U2. The secondary low pass filter module 172 may include a capacitor C13, a resistor R13, a capacitor C20, and a resistor R19. The connection relationship and the functions of the components of the sub-differential to single-ended module 140 and the sub-low-pass filter module 172 refer to fig. 3 and the main differential to single-ended module 120 and the main low-pass filter module 171, which are not described herein again. The secondary high pass filter module 182 includes a capacitor C15 and a resistor R20. The connection relationship and functions of the components of the secondary high-pass filtering module 182 refer to fig. 3 and the primary high-pass filtering module 181, which are not described herein again.
In one embodiment, the echo differential-to-single ended module 160 includes a capacitor C24, a capacitor C26, a resistor R25, a resistor R26, and an operational amplifier U3. The echo low pass filter module 173 may include a capacitor 23, a resistor R24, a resistor R27, and a capacitor C27. The connection relationship and functions of the components of the echo differential-to-single-ended module 160 refer to fig. 3 and the main differential-to-single-ended module 120, which are not described herein again. The connection relationship and functions of the elements of the echo low-pass filter module 173 refer to fig. 3 and the main low-pass filter module 171, which are not described herein again. The echo high-pass filtering module 183 includes a capacitor C25 and a resistor R28. The connection relationship and functions of the elements of the echo high-pass filter module 183 refer to fig. 3 and the main high-pass filter module 181, which are not described herein again.
In one embodiment, the denoising module 150 includes an operational amplification unit, a homodromous filtering unit, and a backward filtering unit. The same-direction input end of the operational amplification unit is connected with the output end of the main differential-to-single-ended module, and the reverse input end of the operational amplification unit is respectively connected with the output end of the auxiliary differential-to-single-ended module and the output end of the echo differential-to-single-ended module. The operational amplification unit is used for filtering the signal input by the reverse input end from the signal input by the same-direction input end. The homodromous filtering unit is connected with the homodromous input end of the operational amplification unit and is used for filtering noise signals of the homodromous input end of the operational amplification unit. The reverse filtering unit is connected with the reverse input end of the operational amplification unit and is used for filtering noise signals at the reverse input end of the operational amplification unit.
In a specific embodiment, the operational amplification unit includes a resistor R14, a resistor R15, a resistor R16, and an operational amplifier U4. The resistor R14 is connected in series between the non-inverting input terminal of the operational amplifier U4 and the output terminal of the main differential-to-single-ended module 120. The resistor R15 is connected in series between the inverting input terminal of the operational amplifier U4 and the output terminal of the sub differential-to-single-ended module 140. The resistor R15 is connected in series between the inverting input terminal of the operational amplifier U4 and the output terminal of the echo differential-to-single-ended module 160. The output of the operational amplifier U4 serves as the output of the noise reduction circuit 10.
The homodromous filtering unit comprises a capacitor C12 and a resistor R11 which are connected in parallel, one end of the capacitor C12 and one end of the resistor R11 are both connected with the homodromous input end of the operational amplifier U4, and the other end of the capacitor C12 and the other end of the resistor R11 are both grounded. The inverse filtering unit comprises a resistor R17 and a capacitor C19 which are connected in parallel, one end of the resistor R17 and one end of the capacitor C19 are both connected with the inverse input end of the operational amplifier U4, and the other end of the resistor R17 and the other end of the capacitor C19 are both connected with the output end of the operational amplifier U4.
An embodiment of the present application further provides a speech recognition module, which includes the noise reduction circuit 10 and the speech recognition circuit as described above. The input end of the voice recognition circuit is connected to the output end of the denoising module 150, and is used for performing voice recognition on the voice signal denoised by the denoising circuit 10. The speech recognition module in this embodiment includes the noise reduction circuit 10 as described above, so that all the beneficial effects of the noise reduction circuit 10 are achieved, and are not described herein again.
An embodiment of the present application further provides an electronic device, which includes the voice recognition module as described above. The electronic device in this embodiment includes the noise reduction circuit 10 as described above, so that all the beneficial effects of the noise reduction circuit 10 are achieved, and are not described herein again.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A noise reduction circuit, comprising:
the main differential driving module is connected with the main sound pickup equipment and used for driving the main sound pickup equipment to work so that the main sound pickup equipment converts collected voice signals into voice differential signals;
the main differential-to-single-ended module is connected with the main differential driving module and used for converting the voice differential signal into a voice single-ended signal;
the auxiliary differential driving module is connected with the auxiliary sound pickup equipment and used for driving the auxiliary sound pickup equipment to work so that the auxiliary sound pickup equipment converts the collected environmental sound signals into environmental differential signals;
the auxiliary differential-to-single-ended module is connected with the auxiliary differential driving module and used for converting the environment differential signal into an environment single-ended signal;
and the denoising module is respectively connected with the main differential to single-ended conversion module and the auxiliary differential to single-ended conversion module and is used for filtering the environment single-ended signal from the voice single-ended signal.
2. The noise reduction circuit of claim 1, further comprising:
the echo differential-to-single-ended module is connected with the audio output unit and used for receiving the echo differential signal output by the audio output unit and converting the echo differential signal into an echo single-ended signal;
the echo differential-to-single-ended module is connected with the denoising module, and the denoising module is further used for filtering the echo single-ended signal from the voice single-ended signal.
3. The noise reduction circuit of claim 2, further comprising:
the main low-pass filtering module is connected with the main differential-to-single-ended module and the denoising module, and is used for filtering high-frequency noise signals in the voice single-ended signals;
the auxiliary low-pass filtering module is connected with the auxiliary differential to single-ended conversion module and the denoising module, and is used for filtering high-frequency noise signals in the environment single-ended signals;
and the echo low-pass filtering module is connected with the echo differential-to-single-ended module and the denoising module, and is used for filtering high-frequency noise signals in the echo single-ended signals.
4. The noise reduction circuit of claim 2, further comprising:
the main high-pass filtering module is connected with the main differential-to-single-ended module and the denoising module, and is used for filtering low-frequency noise signals in the voice single-ended signals;
the auxiliary high-pass filtering module is connected with the auxiliary differential to single-ended conversion module and is connected with the denoising module, and the auxiliary high-pass filtering module is used for filtering low-frequency noise signals in the environment single-ended signals;
and the echo high-pass filtering module is connected with the echo differential-to-single-ended module and the denoising module, and is used for filtering low-frequency noise signals in the echo single-ended signals.
5. The noise reduction circuit of claim 2, wherein the denoising module comprises:
the same-direction input end of the operational amplification unit is connected with the main differential-to-single-ended module, and the reverse input end of the operational amplification unit is respectively connected with the auxiliary differential-to-single-ended module and the echo differential-to-single-ended module;
the homodromous filtering unit is connected with the homodromous input end of the operational amplification unit and is used for filtering noise signals at the homodromous input end of the operational amplification unit;
and the reverse filtering unit is connected with the reverse input end of the operational amplification unit and is used for filtering noise signals at the reverse input end of the operational amplification unit.
6. The noise reduction circuit according to claim 5, wherein the operational amplification unit includes:
an operational amplifier U4, wherein the same-direction input end of the operational amplifier U4 is connected with the same-direction filtering unit, and the reverse input end of the operational amplifier U4 is connected with the reverse filtering unit;
one end of the resistor R14 is connected with the main differential-to-single-ended module, and the other end of the resistor R14 is connected with the equidirectional input end of the operational amplifier U4;
one end of the resistor R16 is connected with the auxiliary differential-to-single-ended module, and the other end of the resistor R16 is connected with the inverting input end of the operational amplifier U4;
one end of the resistor R21 and one end of the resistor R21 are connected with the echo differential-to-single-ended module, and the other end of the resistor R21 is connected with the reverse input end of the operational amplifier U4.
7. The noise reduction circuit of claim 1, wherein the main differential to single-ended module comprises:
one end of the resistor R4 is connected with the positive electrode output end of the main differential drive module;
one end of the resistor R5 is connected with the negative electrode output end of the main differential drive module;
the same-direction input end of the operational amplifier U1 is connected with the other end of the resistor R4, the reverse-direction input end of the operational amplifier U1 is connected with the other end of the resistor R5, and the output end of the operational amplifier U1 is connected with the denoising module.
8. The noise reduction circuit of claim 7, wherein the main differential to single-ended module further comprises:
one end of the capacitor C3 is connected with the positive electrode output end of the main differential drive module, and the other end of the capacitor C3 is connected with one end of the resistor R4;
one end of the capacitor C6, one end of the capacitor C6 is connected to the negative output end of the main differential drive module, and the other end of the capacitor C6 is connected to one end of the resistor R5.
9. A speech recognition module, comprising:
a noise reduction circuit as defined in any one of claims 1 to 8;
and the voice recognition circuit is connected with the denoising module.
10. An electronic device comprising a speech recognition module according to claim 9.
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| CN202010835006.6A CN112086101A (en) | 2020-08-19 | 2020-08-19 | Noise reduction circuit, voice recognition module and electronic equipment |
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