CN219372580U - Audio noise reduction circuit and audio system - Google Patents
Audio noise reduction circuit and audio system Download PDFInfo
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- CN219372580U CN219372580U CN202320058020.9U CN202320058020U CN219372580U CN 219372580 U CN219372580 U CN 219372580U CN 202320058020 U CN202320058020 U CN 202320058020U CN 219372580 U CN219372580 U CN 219372580U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
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Abstract
The utility model discloses an audio noise reduction circuit and an audio system. The audio noise reduction circuit includes: the device comprises a pseudo-differential processing module, a control module and an impedance selection module. The first input end of the pseudo-differential processing module is connected with the analog signal output end of the sound source equipment, the second input end of the pseudo-differential processing module is connected with the reference ground end of the sound source equipment, and the output end of the pseudo-differential processing module is connected with the input end of the audio processor. The control module is electrically connected with the control end of the impedance selection module and is used for generating a control signal according to the grounding state of the sound source equipment and the grounding state of the audio processor; the first end of the impedance selection module is electrically connected with the reference ground end, and the second end of the impedance selection module is electrically connected with the processor ground end of the audio processor; an adjustable impedance is arranged between the first end and the second end of the impedance selection module, and the impedance selection module is used for adjusting the impedance between the first end and the second end of the impedance selection module according to the control signal. The embodiment of the utility model can improve the noise reduction effect on the basis of ensuring the frequency response range, thereby providing better tone quality.
Description
Technical Field
The utility model relates to the technical field of audio transmission, in particular to an audio noise reduction circuit and an audio system.
Background
Sound quality is an important evaluation point for characterizing the quality of an audio system. In audio systems, audio signals are typically output by a sound source device, received by an audio processor, processed, and then forwarded or played. Since analog signals have excellent fidelity and reproducibility, an audio system composed of analog audio source devices occupies a large market. However, analog signals, especially small-signal analog audio, are extremely susceptible to external disturbances, so that the audio analog signals output by the audio source device carry in much disturbance when transmitted to the audio processor. For example, because of the inconsistent impedance to ground of the audio source device and the audio processor, a potential difference exists between the two devices, so that the audio processor collects non-audio signals to introduce interference; or, the audio transmission line between the sound source device and the audio processor brings interference such as electromagnetic waves, ground noise and the like existing in the living environment; still alternatively, as shown in fig. 1, since the audio transmission line 01 is constructed in parallel with the drive line 02 between the other power distribution apparatus and the power receiving apparatus, the audio signal is disturbed by the drive signal on the drive line 02.
In the prior art, an isolation element is generally used to realize the loop isolation between the audio source equipment and the audio processor, or an isolation transformer is arranged to realize the noise reduction treatment in the audio signal transmission process. However, the ground loops are usually isolated by using a fixing element, so that various equivalent ground impedance conditions of the sound source equipment and the audio processor are difficult to adapt, and when the ground state of any equipment is changed, the isolating element cannot be adjusted accordingly, a good isolating effect cannot be achieved, even a reaction is likely to be achieved, and problems caused by interference such as audio current sound cannot be well solved. For the isolation transformer, due to the limitations of a preparation process and the like, the inductive and resistive characteristics of the isolation transformer can influence the transmission of the audio signal in the low frequency range, so that the audio processor cannot receive the low frequency signal, or the received low frequency signal is severely distorted, and the frequency response range and the tone quality of the audio are influenced.
Therefore, the noise reduction scheme in the prior art is difficult to achieve a better noise reduction effect under the condition of ensuring the frequency response range, and is difficult to provide a better sound quality.
Disclosure of Invention
The utility model provides an audio noise reduction circuit and an audio system, which are used for improving the noise reduction effect on the basis of guaranteeing the range of audio response, so as to provide better tone quality.
In a first aspect, an embodiment of the present utility model provides an audio noise reduction circuit, including: the device comprises a pseudo-differential processing module, a control module and an impedance selection module;
the first input end of the pseudo-differential processing module is connected with the analog signal output end of the sound source equipment, the second input end of the pseudo-differential processing module is connected with the reference ground end of the sound source equipment, and the output end of the pseudo-differential processing module is connected with the input end of the audio processor;
the control module is electrically connected with the control end of the impedance selection module; the control module is used for generating a control signal according to the grounding state of the sound source equipment and the grounding state of the audio processor;
the first end of the impedance selection module is electrically connected with the reference ground end, and the second end of the impedance selection module is electrically connected with the processor ground end of the audio processor; the impedance selection module is used for adjusting the impedance between the first end and the second end of the impedance selection module according to the control signal.
Optionally, the impedance selection module includes:
the control end of the selection unit is electrically connected with the control module, and the first end of the selection unit is electrically connected with the reference ground end;
the impedance providing unit is electrically connected with the second end of the selecting unit at the selecting end, and the connecting end of the impedance providing unit is electrically connected with the ground end of the processor; the impedance providing unit comprises a selection end and a connection end, wherein the selection end is used for selecting the impedance between the selection end and the connection end of the impedance providing unit according to the control signal.
Optionally, the selection end includes at least two selection sub-ends, a selection branch is connected between each selection sub-end and the connection end, and the impedance of each selection branch is different; the selection unit determines a selection sub-terminal connected with the second terminal of the selection unit according to the control signal.
Optionally, the impedance of one of the selection branches is 0, and each of the other selection branches includes an alternative resistor connected between the selection sub-terminal and the connection terminal, and the impedance of each alternative resistor is different.
Optionally, the selecting unit comprises at least one switch subunit, the control end of the selecting unit comprises at least one control subunit, and each control subunit is connected with the control end of each switch subunit in a one-to-one correspondence manner; each of the switch subunits includes a first connection terminal and at least one second connection terminal; each second connecting end is connected with each selector end in one-to-one correspondence; each first connecting end is electrically connected with the reference ground end;
the control module is used for generating control signals corresponding to the switch subunits according to the grounding state of the sound source equipment, the grounding state of the audio processor and the impedance of each selected branch.
Optionally, the switch subunit includes: a transistor and a relay;
the control electrode of the transistor is electrically connected with the control end of the switch subunit, the first electrode of the transistor is grounded, the first end of the coil of the relay is connected with a power supply signal, and the second end of the coil of the relay is electrically connected with the second electrode of the transistor; the movable contact of the relay is used as a first connecting end of the switch subunit, and the stationary contact of the relay is used as a second connecting end of the switch subunit.
Optionally, the control module includes: a local control unit and a remote control unit;
the remote control unit is in communication connection with the local control unit, and the local control unit is electrically connected with the control end of the impedance selection module.
Optionally, the pseudo-differential processing module includes: an operational amplifier; the positive input end of the operational amplifier is electrically connected with the reference ground end, the negative input end of the operational amplifier is electrically connected with the analog signal output end, and the output end of the operational amplifier is electrically connected with the input end of the audio processor.
Optionally, the audio source device is connected with the pseudo-differential processing module through a transmission line, the transmission line includes a signal line and a ground line, the analog signal output end is connected with the first input end of the pseudo-differential processing module through the signal line, the reference ground end is connected with the second input end of the pseudo-differential processing module through the ground line, and the first end of the impedance selection module is connected with the second input end of the pseudo-differential processing module.
In a second aspect, an embodiment of the present utility model further provides an audio system, including: an audio source device, an audio processor, and an audio noise reduction circuit provided by any of the embodiments of the present utility model.
The audio noise reduction circuit provided by the embodiment of the utility model is provided with a pseudo-differential processing module, a control module and an impedance selection module. The pseudo-differential processing module performs pseudo-differential processing on the analog signals output by the sound source equipment based on the reference ground signals of the sound source equipment, so that common mode interference in the analog signals in the full frequency response range can be basically eliminated. Meanwhile, the impedance selection module is set as a functional module with adjustable impedance, and the control module can adjust the impedance between the first end and the second end of the impedance selection module according to the grounding states of the sound source equipment and the audio processor so as to realize impedance matching on a grounding signal transmission path aiming at various access of the sound source equipment and various operation conditions, and eliminate interference signals caused by different grounding states of the sound source equipment and the audio processor, such as different equivalent grounding impedances. In summary, compared with the prior art, the embodiment of the utility model can effectively reduce audio noise, realize high-fidelity acquisition and transmission of audio analog signals, improve the noise reduction effect on the basis of guaranteeing the frequency response range, and provide better sound quality.
It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the utility model or to delineate the scope of the utility model. Other features of the present utility model will become apparent from the description that follows.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a structure in which an audio transmission line and a driving line are disposed in parallel;
fig. 2 is a schematic structural diagram of an audio noise reduction circuit according to an embodiment of the present utility model;
FIG. 3 is a schematic diagram of another audio noise reduction circuit according to an embodiment of the present utility model;
fig. 4 is a schematic diagram of a connection relationship between a control module and an impedance selection module according to an embodiment of the present utility model;
fig. 5 is a schematic structural diagram of an impedance selecting module according to an embodiment of the present utility model;
fig. 6 is a schematic structural diagram of a switch subunit according to an embodiment of the present utility model;
fig. 7 is a schematic structural diagram of an audio system according to an embodiment of the present utility model.
Detailed Description
In order that those skilled in the art will better understand the present utility model, a technical solution in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present utility model without making any inventive effort, shall fall within the scope of the present utility model.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present utility model and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the utility model described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion.
The embodiment of the utility model provides an audio noise reduction circuit. Fig. 2 is a schematic structural diagram of an audio noise reduction circuit according to an embodiment of the present utility model. Referring to fig. 2, the audio noise reduction circuit 10 includes: a pseudo-differential processing module 110, a control module 120, and an impedance selection module 130.
The first input end of the pseudo-differential processing module 110 is connected to the analog signal output end of the audio source device 20, the second input end of the pseudo-differential processing module 110 is connected to the reference ground end of the audio source device 20, and the output end of the pseudo-differential processing module 110 is connected to the input end of the audio processor 30. The control module 120 is electrically connected with the control end of the impedance selection module 130; the control module 120 is configured to generate a control signal according to a ground state of the sound source device 20 and a ground state of the audio processor 30. The first end of the impedance selection module 130 is electrically connected with the reference ground and is connected with the reference ground signal GND1; the second terminal of the impedance selecting module 130 is electrically connected to the processor ground terminal of the audio processor 30, and is connected to the processor ground signal GND2. The impedance selection module 130 has an adjustable impedance between the first end and the second end, and the impedance selection module 130 is configured to adjust the impedance between the first end and the second end of the impedance selection module 130 according to the control signal.
Illustratively, the audio source device 20 may be an analog audio source device and the audio processor 30 may be integrated in an audio processing device. The ground state of the sound source device 20 may include whether a ground terminal is provided in the sound source device 20, and the magnitude of the equivalent impedance to ground of the sound source device 20 when the ground terminal is provided in the sound source device 20. Likewise, the ground state of the audio processor 30 may include whether a ground is provided in the audio processor 30, and the magnitude of the equivalent impedance to ground of the audio processor 30 when a ground is provided in the audio processor 30. At least one grounding terminal is required to be disposed in the audio system, and the grounding terminal is disposed in at least one device of the audio source device 20 and the audio processor 30, for example.
The reference ground signal GND1 is used for characterizing the ground state of the audio source device 20 and the processor ground signal GND2 is used for characterizing the ground state of the audio processor 30. The determination of the impedance between the first and second ends of the impedance selection module 130 is related to the ground state of both the sound source device 20 and the audio processor 30. For convenience of description, the impedance between the first and second ends of the impedance selection module 130 is defined as an isolation impedance in the following explanation process. The selection rule of the isolation impedance is determined according to the matching relationship of the ground state of the sound source device 20 and the ground state of the audio processor 30, and an exemplary description is made below.
Illustratively, when any one of the sound source device 20 and the audio processor 30 is provided with a ground terminal, it is desirable that the smaller the impedance value of the isolation impedance, the better, even 0, so as to circulate with the electric signal to the ground terminal, and to minimize the impedance on the ground signal circulation path, achieving good grounding of the sound source device 20 and the audio processor 30. Taking the example of setting the ground terminal in the audio source device 20 as an example, the reference ground signal GND1 may be understood as a potential signal obtained after the audio source device ground passes through the equivalent ground impedance of the audio source device 20, and the processor ground signal GND2 may be understood as a signal to be grounded of the audio processor 30, which needs to be grounded through the audio source device after passing through the reference ground terminal. At this time, the isolation impedance may be set to 0 so as to equalize the potentials of the reference ground signal GND1 and the processor ground signal GND2 as much as possible.
When the ground terminals are provided in both the sound source device 20 and the audio processor 30, the reference ground signal GND1 may be understood as a potential signal obtained by passing the sound source device ground through the equivalent ground impedance of the sound source device 20, and the processor ground signal GND2 may be understood as a potential signal obtained by passing the processor ground through the equivalent ground impedance of the audio processor 30. Illustratively, the source device ground and the processor ground may each be a unified earth ground. The equivalent ground impedance described above may originate from the connection lines in the device as well as other functional elements in the device. At this time, when the equivalent impedance to ground at both ends is 0, the isolation impedance may be set to 0. When the equivalent impedance to the ground at both ends is not 0, the value of the isolation impedance can be matched according to the values of the two equivalent impedances to the ground. Illustratively, the equivalent impedance to ground of the sound source device 20 is denoted as R1, the equivalent impedance to ground of the audio processor 30 is denoted as R2, and the isolation impedance is denoted as R. When R2 > R1, the processor ground signal GND2 flows through the sound source device at the front end in the opposite direction, and the isolation impedance R may be set as small as possible to provide a smooth signal flow path. When R2 is less than R1, the reference ground signal GND1 will flow to the processor ground at the rear end, where the isolation impedance R may be set as large as possible to prevent the ground signal at the end of the sound source device 20 from being transmitted backward, so that it returns to its own sound source device ground.
In summary, the control module 120 may determine whether to lower or raise the potential difference between the reference ground and the receiver ground according to the ground state of the audio source device 20 and the audio processor 30 and the position of the ground point in the audio system, so as to select the value of the isolation impedance. Illustratively, the control module 120 may obtain the grounding states of the audio processor 30 and the audio source device 20 according to the operation conditions of the audio system (such as the operation environment, the connection mode of each transmission line, the access state and the access mode of the audio source device 20, etc.).
Illustratively, an adjustable resistor, such as a potentiometer, may be disposed between the first and second ends of the impedance selection module 130. The first end of the impedance selection module 130 may be connected to the sliding end of the adjustable resistor, and the second end may be connected to the fixed end of the adjustable resistor. The control module 120 may adjust the size of the isolation resistor by adjusting the position of the sliding end of the adjustable resistor. Alternatively, a plurality of impedance branches with different impedance values may be disposed between the first end and the second end of the impedance selection module 130, and the control module 120 may determine the size of the isolation resistor by selecting the impedance branch that is communicated between the first end and the second end of the impedance selection module 130.
The pseudo-differential processing module 110 receives the analog signal output by the analog signal output end of the audio source device 20, and simultaneously accesses the reference ground signal GND1 of the audio source device 20, which is equivalent to that by introducing the reference ground signal GND1, the pseudo-differential processing of the analog signal is realized by making the difference between the analog signal and the reference ground signal GND1, so as to eliminate common mode interference in the signal transmission process. Specifically, the signal lines for transmitting the analog signal and the reference ground signal GND1 may be arranged in parallel, and thus, substantially the same synchronous interference exists on both signal lines, and the interference is substantially eliminated by the differential processing of the pseudo-differential processing module 110, so that the signal transmitted to the audio processor 30 is an effective signal with high reducibility and high fidelity. In addition, compared with the scheme that the isolation transformer is used to lose the audio frequency of the low-frequency part, the pseudo-differential processing module 110 can be used for effectively pseudo-differential processing of the analog signals in the full frequency response range in the human hearing range, and the loss of the frequency response range is avoided. Illustratively, the analog signals may include a left channel analog signal and a right channel analog signal, and the pseudo-differential processing module 110 may respectively perform a difference process on the two analog signals with the reference ground signal GND1.
Illustratively, the audio processor 30 is disposed in an audio processing device, and the audio processor 30 may be grounded through any ground in the audio processing device. The pseudo-differential processing module 110 may be integrated into the audio processing device or may be provided separately from the audio processing device. The impedance selection module 130 may be integrated into the audio processing device or may be provided separately from the audio processing device. The control module 120 may include a local control unit, which may be implemented directly by a processor in the audio processing device or may be configured independently of the audio processing device; the control module 120 may also include a remote control unit to enable remote control of the operating state of the audio system. The setting positions of the functional modules are not limited in this embodiment, and may be specifically set according to actual requirements.
In the audio noise reduction circuit 10 provided in the embodiment of the present utility model, a pseudo-differential processing module 110, a control module 120, and an impedance selecting module 130 are provided. The pseudo-differential processing module 110 performs pseudo-differential processing on the analog signal output by the sound source device 20 based on the reference ground signal GND1 of the sound source device 20, and can substantially eliminate common-mode interference in the analog signal within the full frequency response range. Meanwhile, the impedance selection module 130 is configured as a functional module with adjustable impedance, and the control module 120 can adjust the impedance between the first end and the second end of the impedance selection module 130 according to the grounding states of the audio source device 20 and the audio processor 30, so as to realize impedance matching on a grounding signal transmission path for various operation conditions and eliminate interference signals caused by different grounding states of the audio source device 20 and the audio processor 30, such as different equivalent grounding impedances. In summary, compared with the prior art, the embodiment of the utility model can effectively reduce audio noise, realize high-fidelity acquisition and transmission of audio analog signals, and improve the noise reduction effect on the basis of guaranteeing the frequency response range, thereby providing better sound quality.
The above embodiments exemplarily give the operation modes of each functional module in the audio noise reduction circuit, and a specific structure that each functional module may have will be described below.
Fig. 3 is a schematic diagram of another audio noise reduction circuit according to an embodiment of the present utility model. Referring to fig. 3, in one embodiment, the pseudo-differential processing module 110 optionally includes: an operational amplifier U1. The positive input terminal of the operational amplifier U1 is electrically connected to the reference ground terminal as the second input terminal of the pseudo-differential processing module 110, and is connected to the reference ground signal GND1. The negative input end of the operational amplifier U1 is used as a first input end of the pseudo-differential processing module 110, and is electrically connected with the analog signal output end, and is connected with an audio analog signal. The output of the operational amplifier U1 is electrically connected to the input of the audio processor 30 as the output of the pseudo-differential processing module 110. The pseudo-differential processing module 110 is configured based on the operational amplifier U1 in the present embodiment, so that the pseudo-differential processing module 110 has a simple structure and low cost.
Further, in order to ensure the working stability of the operational amplifier U1, a peripheral circuit including a capacitor and a resistor may be further provided, for example, a filter capacitor and a resistor are connected to both input terminals of the operational amplifier U1, and a feedback resistor is connected between the negative input terminal and the output terminal of the operational amplifier U1, or any peripheral structure in the prior art may be provided, which is not limited herein.
With continued reference to fig. 3, the audio source device 20 is optionally connected to the pseudo-differential processing module 110 through a transmission line 50, on the basis of the above embodiments. The transmission line 50 may include a signal line 51 and a ground line 52. The signal line 51 and the ground line 52 may be twisted wires or arranged in parallel. The analog signal output is connected to a first input of the pseudo-differential processing module 110 via a signal line 51, the reference ground is connected to a second input of the pseudo-differential processing module 110 via a ground line 52, and the first end of the impedance selection module 130 is connected to the second input of the pseudo-differential processing module 110. Illustratively, the signal lines 51 may include a left channel signal line and a right channel signal line for transmitting a left channel analog signal and a right channel analog signal, respectively, to ensure fidelity of the audio signal.
With continued reference to fig. 3, in addition to the above embodiments, optionally, a speaker, such as a speaker 40, coupled to the audio processor 30 may be included in the audio system for playing audio signals. And, other audio source devices and other audio processors may also be included in the audio system; the audio source device 20 may also transmit audio signals to other audio processors, and the audio processor 30 may also receive audio signals transmitted by other audio source devices. That is, each device in the audio system has a receiving end and a transmitting end, which form a complex interconnection structure. Therefore, the control module 120 can actually perform the value of the isolation impedance according to the specific interconnection relationship collocation in the audio system, so as to balance the impedance relationship on the ground signal transmission path between all the devices. And, in the audio system, an adjustable impedance can be set between the ground signal ends of any other two interconnection devices, and the control module 120 can also be used for adjusting any other adjustable impedance.
Fig. 4 is a schematic diagram of a connection relationship between a control module and an impedance selection module according to an embodiment of the present utility model. Referring to fig. 4, in one embodiment, optionally, the control module 120 includes: a local control unit 121 and a remote control unit 122. The remote control unit 122 is communicatively connected to the local control unit 121, and the local control unit 121 is electrically connected to a control terminal of the impedance selection module 130.
The remote control unit 122 can remotely access the audio processing device, specifically, the remote control unit 122 can send out related remote operation instructions according to the grounding state of the audio source device 20 and the audio processor 30; after receiving the remote operation command, the local control unit 120 converts the remote operation command into a local control command, i.e. a control signal, and transmits the control signal to the impedance selection module 130. Alternatively, the local control unit 120 may directly generate a control signal according to the grounding state of the audio source device 20 and the audio processor 30, and the remote control unit 122 may be configured to implement other background control functions.
The local control unit 121 may be integrated in an audio processing device, for example. Both the local control unit 121 and the remote control unit 122 may be implemented by using control units existing in the audio system. For example, the audio system itself is a networking system, and the local control unit 121 and the remote control unit 122 are already executing various functions of the background operation and maintenance, and the control method of the embodiment of the present utility model can be implemented only by adding or upgrading functions of the original two control units, so as to reduce implementation cost of the embodiment of the present utility model.
With continued reference to fig. 4, the impedance selection module 130 may specifically include, based on the above embodiments: a selection unit 131 and an impedance providing unit 132. The control terminal J3 of the selection unit 131 is electrically connected to the control module 120. The first terminal J1 of the selection unit 131 is electrically connected to the reference ground, the second terminal J2 of the selection unit 131 is electrically connected to the selection terminal J4 of the impedance providing unit 132, and the connection terminal J5 of the impedance providing unit 132 is electrically connected to the processor ground. The impedance providing unit 132 has an adjustable impedance between the selection terminal J4 and the connection terminal J5, and the selection unit 131 is configured to select the impedance between the selection terminal J4 and the connection terminal J5 of the impedance providing unit 132 according to the control signal.
The selection unit 131 may be electrically connected to the local control unit 121 as a local execution mechanism. The impedance providing unit 132 serves as a gating item component, and the selecting unit 131 performs a corresponding action under the control of the local control unit 121, thereby determining the final impedance between the selecting terminal J4 and the connecting terminal J5 of the impedance providing unit 132. Illustratively, the selecting unit 131 may be a software-controlled based switching component, and the impedance providing unit 132 may include a plurality of selecting branches of different impedances, and the selecting unit 131 determines the selecting branches to which the switching component communicates based on the control signal to achieve impedance selection.
Based on the above embodiments, optionally, an intelligent judging system may be configured in the control module 120, where the intelligent judging system may obtain a current state of the audio system and a connection relationship between each device in the audio system, and determine which audio quality in the audio system has a problem by analyzing the obtained audio file and analyzing the feature quantity of the recorded sound. After the impedance is adjusted, the intelligent judgment system can acquire the changed audio file again so as to ensure that the audio quality is improved. The audio system may be a multi-input channel system, and when one or more input audio in the system has problems, the method provided by the embodiment of the utility model can be used for adjusting impedance. Illustratively, the intelligent judgment system may be integrated in the remote control unit 122, in the local control unit 121, or in any processor in the control system of the audio system. And when the audio system is a multi-input channel system, the intelligent judgment system can be arranged for multiple channels simultaneously.
Specific structures that the selection unit 131 and the impedance providing unit 132 may have are described below, but are not limiting of the present utility model.
Fig. 5 is a schematic structural diagram of an impedance selecting module according to an embodiment of the present utility model. Referring to fig. 5, in one embodiment, the selection terminal J4 optionally includes at least two selection sub-terminals, such as selection sub-terminals N0 to Nn in order from bottom to top in fig. 5. A selection branch 610 is connected between each selection sub-terminal and the connection terminal J5, and the impedance of each selection branch 610 is different; the selecting unit 131 determines a selecting sub-terminal connected to the second terminal J2 of the selecting unit 131 according to the control signal, thereby determining a selecting sub-terminal in communication with the reference ground terminal to select the corresponding selecting branch 610, and completing the selection of the impedance. Illustratively, the connection terminal J5 may also be provided with connection sub-terminals 51 corresponding to the selection branches 610 one by one, so as to implement connection between each selection branch 610 and the ground terminal of the processor.
Specifically, each selection branch may include an alternative resistor connected between the selection sub-terminal and the connection sub-terminal, and the impedance of each selection branch is different by setting the alternative resistor to be different. In addition, an impedance of one selection branch 610 may be set to 0, so as to directly connect the corresponding selection sub-terminal and the connection sub-terminal 51. The impedance of each selection branch 610 may be ordered according to a preset rule, so as to facilitate the selection of the selection sub-terminal by the selection unit 131. Illustratively, a first selection branch 610 may be provided as a wire in a bottom-to-top direction, with the alternate resistances RB 1-RBn in the remaining selection branches 610 increasing in sequence.
With continued reference to fig. 5, the selection unit 131 may optionally include at least one switch subunit 710, where the switch subunit 710 is shown in fig. 5 as a switch-like diagram, but does not represent a specific structure of the switch subunit 710. Illustratively, the switch subunit 710 may be any form of controllable switch, such as a relay, a transistor, a digital switch, or an analog switch.
The control end of the selecting unit 131 includes at least one control sub-end, and each control sub-end is connected with the control end 73 of each switch sub-unit 710 in a one-to-one correspondence manner; each switch subunit 710 includes a first connection 71 and at least one second connection 72. The second connection terminals 72 included in the selection unit 131 are connected to the selection sub-terminals in the impedance providing unit 132 in a one-to-one correspondence. Each first connection terminal 71 is electrically connected to a reference ground terminal. The control module is configured to generate control signals corresponding to the switch subunits 710 according to the ground state of the audio source device, the ground state of the audio processor, and the impedance of each selection branch 610.
Specifically, the selecting unit 131 may include only one switching sub-unit 710, and the switching sub-unit 710 includes n+1 second connection terminals 72, which are connected in one-to-one correspondence with the respective selecting sub-terminals. The control module generates 1 control signal from which the switching subunit 710 can determine the target second connection 72 in communication with the first connection 71. By this arrangement, the audio noise reduction circuit structure can be simplified.
Alternatively, the selection unit 131 may include n+1 switching sub-units 710, each of the switching sub-units 710 including 1 second connection terminal 72. Each switch subunit 710 may default to an off state, or default to one switch subunit 710 on and the other switch subunits 710 off. The control module may generate n+1 control signals corresponding to each switch subunit 710 according to the grounding states of the audio source device and the audio processor, where the control signal corresponding to the target switch subunit 710 is a conducting signal. Illustratively, the target switching subunit 710 may be 1, and when one selection branch 610 fails to provide the desired impedance, the target switching subunit 710 may also be multiple, providing more selectable impedance values through parallel connection of multiple alternative resistors, so that the final impedance value is closer to the desired impedance. By the arrangement, the switch instruction in the control signal can be accurately corresponding to each selection branch 610 (namely different impedance values), so that the accuracy and flexibility of impedance selection are ensured.
Still alternatively, the number of the switching sub-units 710 in the selection unit 131 may be between 1 and n+1, and at least part of the switching sub-units 710 may include two or more second connection terminals 72. The control module controls the communication state between the first connection terminal 71 and the second connection terminal 72 in each switch subunit 710 by adjusting specific values of each control signal. The specific setting mode can be set according to actual requirements.
In particular, referring to fig. 6, in one embodiment, optionally, the switch subunit comprises: a transistor Q1 and a relay 711. The control electrode of the transistor Q1 is used as the control terminal 73 of the switching subunit, and is connected to the control signal line_in_relay corresponding to the switching subunit. The first electrode of the transistor Q1 is grounded, a first end of a Coil of the relay 711 is connected with a power supply signal VCC, and a second end of the Coil of the relay 711 is electrically connected with a second electrode of the transistor Q1; the moving contact of the relay 711 serves as the first connection terminal 71 of the switch subunit, and the stationary contact of the relay 711 serves as the second connection terminal 72 of the switch subunit.
Illustratively, the control signal line_in_relay controls whether the Coil of the Relay 711 is energized or not by controlling the conduction or non-conduction of the transistor Q1, thereby controlling the connection relationship between the movable contact and the stationary contact of the Relay 711. In fig. 6, the relay 711 is exemplified as including a single-pole switch and including two stationary contacts, but the present utility model is not limited thereto, and in other embodiments, the relay may be provided as including a double-pole switch and other numbers of stationary contacts.
Further, a protection resistor R1 may be further disposed between the gate of the transistor Q1 and the control terminal of the switch subunit; a freewheeling diode D1 may be connected in parallel across the Coil of the relay 711 as a discharge path for the Coil. The power supply signal VCC may be a 5V dc voltage signal, for example; the control signal line_in_relay may be provided by a GPIO port of the local control unit.
In summary, the embodiment of the utility model designs an audio noise reduction circuit optimization design scheme capable of adapting according to a scene and a specific circuit implementation, and can provide a noise reduction circuit with low cost and high integration level. The pseudo-differential processing module 110 may perform noise filtering to convert the analog audio single-ended signal into a pseudo-differential signal, thereby directly picking up the active components in the signal, blocking the problem of potential difference of the reference ground potential due to transmission line interference or interconnection of a plurality of devices, and realizing high fidelity on the basis of ensuring the audio frequency range. The control module 120 can control the impedance value of the impedance selection module 130 according to the grounding state of the audio source device 20 and the audio processor 30, so that the audio noise reduction circuit can adapt to various complex environments of the device site, the same audio system can be used in different environments, and audio noise does not occur when the same audio system is simultaneously connected to different audio source devices for use. And the control module 120 can realize remote control or local control without participation of professional technicians, so that maintenance cost is reduced.
The embodiment of the utility model also provides an audio system which comprises the audio noise reduction circuit provided by any embodiment of the utility model and has corresponding beneficial effects. Fig. 7 is a schematic structural diagram of an audio system according to an embodiment of the present utility model. Referring to fig. 7, the audio system includes an audio source device 20, an audio noise reduction circuit 10, and an audio processor 30, which are connected in this order, for example.
The audio noise reduction circuit 10 and the audio processor 30 may be completely separately disposed, or at least some functional modules in the audio noise reduction circuit 10 and the audio processor 30 may be integrated into the audio processing device. And, functional devices such as speakers connected to the audio processor 30 may also be included in the audio system.
It should be noted that, the structure of the audio system related to each embodiment of the audio noise reduction circuit may be considered as the configuration mode of the audio system provided in the embodiment of the present utility model, and repeated descriptions are omitted herein.
The above embodiments do not limit the scope of the present utility model. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included in the scope of the present utility model.
Claims (10)
1. An audio noise reduction circuit, comprising: the device comprises a pseudo-differential processing module, a control module and an impedance selection module;
the first input end of the pseudo-differential processing module is connected with the analog signal output end of the sound source equipment, the second input end of the pseudo-differential processing module is connected with the reference ground end of the sound source equipment, and the output end of the pseudo-differential processing module is connected with the input end of the audio processor;
the control module is electrically connected with the control end of the impedance selection module; the control module is used for generating a control signal according to the grounding state of the sound source equipment and the grounding state of the audio processor;
the first end of the impedance selection module is electrically connected with the reference ground end, and the second end of the impedance selection module is electrically connected with the processor ground end of the audio processor; the impedance selection module is used for adjusting the impedance between the first end and the second end of the impedance selection module according to the control signal.
2. The audio noise reduction circuit of claim 1, wherein the impedance selection module comprises:
the control end of the selection unit is electrically connected with the control module, and the first end of the selection unit is electrically connected with the reference ground end;
the impedance providing unit is electrically connected with the second end of the selecting unit at the selecting end, and the connecting end of the impedance providing unit is electrically connected with the ground end of the processor; the impedance providing unit comprises a selection end and a connection end, wherein the selection end is used for selecting the impedance between the selection end and the connection end of the impedance providing unit according to the control signal.
3. The audio noise reduction circuit according to claim 2, wherein the selection terminal comprises at least two selection sub-terminals, a selection branch is connected between each selection sub-terminal and the connection terminal, and the impedance of each selection branch is different; the selection unit determines a selection sub-terminal connected with the second terminal of the selection unit according to the control signal.
4. An audio noise reduction circuit according to claim 3, wherein the impedance of one of said selection branches is 0, each of the other selection branches comprises an alternative resistor connected between said selection sub-terminal and said connection terminal, and the impedance of each of said alternative resistors is different.
5. The audio noise reduction circuit according to claim 3 or 4, wherein the selection unit comprises at least one switch subunit, the control end of the selection unit comprises at least one control subunit, and each control subunit is connected with the control end of each switch subunit in a one-to-one correspondence; each of the switch subunits includes a first connection terminal and at least one second connection terminal; each second connecting end is connected with each selector end in one-to-one correspondence; each first connecting end is electrically connected with the reference ground end;
the control module is used for generating control signals corresponding to the switch subunits according to the grounding state of the sound source equipment, the grounding state of the audio processor and the impedance of each selected branch.
6. The audio noise reduction circuit of claim 5, wherein the switch subunit comprises: a transistor and a relay;
the control electrode of the transistor is electrically connected with the control end of the switch subunit, the first electrode of the transistor is grounded, the first end of the coil of the relay is connected with a power supply signal, and the second end of the coil of the relay is electrically connected with the second electrode of the transistor; the movable contact of the relay is used as a first connecting end of the switch subunit, and the stationary contact of the relay is used as a second connecting end of the switch subunit.
7. The audio noise reduction circuit of claim 1, wherein the control module comprises: a local control unit and a remote control unit;
the remote control unit is in communication connection with the local control unit, and the local control unit is electrically connected with the control end of the impedance selection module.
8. The audio noise reduction circuit of claim 1, wherein the pseudo-differential processing module comprises: an operational amplifier; the positive input end of the operational amplifier is electrically connected with the reference ground end, the negative input end of the operational amplifier is electrically connected with the analog signal output end, and the output end of the operational amplifier is electrically connected with the input end of the audio processor.
9. The audio noise reduction circuit according to claim 1, wherein the sound source device is connected to the pseudo-differential processing module through a transmission line, the transmission line includes a signal line and a ground line, the analog signal output terminal is connected to a first input terminal of the pseudo-differential processing module through the signal line, the reference ground terminal is connected to a second input terminal of the pseudo-differential processing module through the ground line, and the first terminal of the impedance selection module is connected to a second input terminal of the pseudo-differential processing module.
10. An audio system, comprising: a sound source device, an audio processor and an audio noise reduction circuit as claimed in any one of claims 1 to 9.
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| CN202320058020.9U CN219372580U (en) | 2023-01-04 | 2023-01-04 | Audio noise reduction circuit and audio system |
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| CN202320058020.9U CN219372580U (en) | 2023-01-04 | 2023-01-04 | Audio noise reduction circuit and audio system |
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| CN202320058020.9U Active CN219372580U (en) | 2023-01-04 | 2023-01-04 | Audio noise reduction circuit and audio system |
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