CN114268894B - Active microphone control circuit - Google Patents
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- CN114268894B CN114268894B CN202210191089.9A CN202210191089A CN114268894B CN 114268894 B CN114268894 B CN 114268894B CN 202210191089 A CN202210191089 A CN 202210191089A CN 114268894 B CN114268894 B CN 114268894B
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Abstract
The application relates to an active microphone control circuit, active microphone control circuit includes: the microphone input unit is used for acquiring an input first voice signal, and the first voice signal comprises a first differential signal and a second differential signal; the gain adjusting unit is electrically connected with the microphone input unit and used for amplifying the first voice signal to obtain an amplified second voice signal; and the processing unit is electrically connected with the gain adjusting unit and is used for processing the second voice signal. According to the method and the device, the input first voice signal comprising the first differential signal and the second differential signal is acquired by the microphone input unit, the gain adjusting unit is used for amplifying the first voice signal to obtain the amplified second voice signal, the processing unit is used for processing the second voice signal, the adjustment of the gain before the voice signal processing can be realized, the processing unit at the rear end can process the voice signal more conveniently, and the processing efficiency of the voice signal is improved.
Description
Technical Field
The application relates to the technical field of voice processing, in particular to an active microphone control circuit.
Background
With the increasing of electronic devices In a Vehicle, In order to effectively reduce common mode interference of voice signals In a transmission process and improve the anti-interference capability and signal-to-noise ratio of voice, a Vehicle-mounted information entertainment system (IVI) controller or a Telematics BOX (T-BOX) adopts a differential Vehicle-mounted active microphone interface circuit. The main parameters of the current vehicle-mounted active microphone are as follows in table 1:
table 1 main parameters of active microphone in related art
| Sensitivity of the probe | -3.5dB±3dB |
| Frequency response | 100-10KHz（±3dB） |
| Electric current | 6±3mA |
| Standard operating voltage | 8V |
| Signal to noise ratio | >62dB |
| Total harmonic distortion | <1% |
Fig. 1 shows a schematic diagram of a related art in-vehicle active microphone circuit. As shown in fig. 1, in the related art, the vehicle-mounted active microphone circuit is composed of a microphone (i.e., a microphone) and an amplifier circuit (i.e., an amplifier), and is electrically connected to a resistor R1 and a resistor R2 through connectors (i.e., a connector), and the resistances of the resistor R1 and the resistor R2 may be 330 ohms. VCC may be 8V. The capacitor C1 and the capacitor C2 serve as dc blocking capacitors, and send the differential signals MIC +, MIC-to a back-end Circuit (e.g., a microphone Application Circuit) for processing.
As can be seen from table 1 and fig. 1, the vehicle-mounted active microphone of the related art has at least the following disadvantages: (1) adjustment of the gain cannot be achieved. When the difference signal of the accessed active microphone needs to be increased or reduced, the difference signal cannot be realized on a hardware circuit, so that the amplitude of the signal entering a back-end circuit is too small to be identified, or the amplitude of the signal is too large, and clipping is caused; (2) when the back end circuit of the active microphone needs a single-ended signal, the differential signal cannot be directly used; (3) faults such as short circuit, open circuit and the like of an active microphone circuit cannot be processed in time.
Disclosure of Invention
In view of this, the present application provides an active microphone control circuit, which can adjust the gain before processing a voice signal, and is beneficial for a processing unit at the rear end to process the voice signal more conveniently, thereby improving the processing efficiency of the voice signal.
According to an aspect of the present application, there is provided an active microphone control circuit including: the microphone input unit is used for acquiring an input first voice signal, wherein the first voice signal comprises a first differential signal and a second differential signal; the gain adjusting unit is electrically connected with the microphone input unit and is used for amplifying the first voice signal to obtain an amplified second voice signal; and the processing unit is electrically connected with the gain adjusting unit and is used for processing the second voice signal.
Further, the gain adjustment unit includes an amplifier, and the amplifier includes a positive input terminal, a negative input terminal, and an output terminal, where the positive input terminal of the amplifier is configured to receive the first differential signal; the negative input end of the amplifier is used for receiving the second differential signal; the output end of the amplifier is electrically connected with the processing unit.
Further, the gain adjustment unit further includes an amplifier peripheral circuit, where the amplifier peripheral circuit includes a first resistor, a first capacitor, a second resistor, and a second capacitor, where one end of the first capacitor is electrically connected to the first differential signal, the other end of the first capacitor is electrically connected to one end of the first resistor, and the other end of the first resistor is electrically connected to the positive input end of the amplifier; one end of the second capacitor is electrically connected to the second differential signal, the other end of the second capacitor is electrically connected to one end of the second resistor, and the other end of the second resistor is electrically connected to the positive input end of the amplifier.
Furthermore, the amplifier peripheral circuit further includes a third resistor and a third capacitor, where the third resistor and the third capacitor are connected in parallel, and one end of the third resistor and one end of the third capacitor are respectively electrically connected to the positive input end of the amplifier; the other end of the third resistor and the other end of the third capacitor are respectively grounded.
Further, the amplifier peripheral circuit further includes a fourth resistor and a fourth capacitor, where the fourth resistor and the fourth capacitor are connected in parallel, and one end of the fourth resistor and one end of the fourth capacitor are electrically connected to the negative input terminal of the amplifier, respectively; the other end of the fourth resistor and the other end of the fourth capacitor are electrically connected with the output end of the amplifier respectively.
Further, the gain of the gain adjusting unit is adjusted according to the first resistor, the second resistor, the third resistor and the fourth resistor.
Furthermore, the active microphone control circuit further includes a fifth resistor, a fifth capacitor and a sixth capacitor, wherein one end of the fifth capacitor is electrically connected to the output end of the amplifier, the other end of the fifth capacitor is electrically connected to one end of the fifth capacitor, and the other end of the fifth capacitor is electrically connected to the processing unit; one end of the sixth capacitor is electrically connected with one end of the fifth capacitor, and the other end of the sixth capacitor is grounded.
Furthermore, the active microphone control circuit further includes a single-ended adjustment unit, where the single-ended adjustment unit includes a sixth resistor and a seventh resistor, where one end of the sixth resistor is electrically connected to one end of the sixth capacitor, and the other end of the sixth resistor is grounded; one end of the seventh resistor is electrically connected with one end of the first capacitor, and the other end of the seventh resistor is electrically connected with one end of the sixth resistor.
Further, the active microphone interface circuit further includes a first diagnosis detection unit, where the first diagnosis detection unit includes an eighth resistor, a ninth resistor, a tenth resistor, a seventh capacitor, an eighth capacitor, and a first processor, where one end of the eighth resistor is electrically connected to one end of the first capacitor, and the other end of the eighth resistor is electrically connected to one end of the ninth resistor, one end of the tenth resistor, and one end of the eighth capacitor, respectively; the other end of the tenth resistor and the other end of the eighth capacitor are grounded; the other end of the ninth resistor is electrically connected with one end of a seventh capacitor and the first processor respectively, and the other end of the seventh capacitor is grounded.
Further, the active microphone interface circuit further includes a second diagnosis detection unit, where the second diagnosis detection unit includes an eleventh resistor, a twelfth resistor, a thirteenth resistor, a ninth capacitor, a tenth capacitor, and a second processor, where one end of the eleventh resistor is electrically connected to one end of the second capacitor, and the other end of the eleventh resistor is electrically connected to one end of the thirteenth resistor, one end of the twelfth resistor, and one end of the tenth capacitor, respectively; the other end of the thirteenth resistor and the other end of the tenth capacitor are grounded; the other end of the twelfth resistor is electrically connected with one end of a ninth capacitor and the second processor respectively, and the other end of the ninth capacitor is grounded.
The method comprises the steps of acquiring an input first voice signal comprising a first differential signal and a second differential signal by using a microphone input unit, amplifying the first voice signal by using a gain adjusting unit to obtain an amplified second voice signal, and processing the second voice signal by using a processing unit.
Drawings
The technical solution and other advantages of the present application will become apparent from the detailed description of the embodiments of the present application with reference to the accompanying drawings.
Fig. 1 shows a schematic diagram of a related art in-vehicle active microphone circuit.
Fig. 2 shows a block diagram of an active microphone control circuit of an embodiment of the present application.
Fig. 3 shows a block diagram of an active microphone control circuit of an embodiment of the present application.
Fig. 4 shows a block diagram of an active microphone control circuit of an embodiment of the present application.
Fig. 5 shows a schematic diagram of an active microphone control circuit of an embodiment of the present application.
Fig. 6 is a schematic diagram illustrating the amplitude of the output signal of the gain adjustment unit according to the embodiment of the present application.
Fig. 7 shows a frequency response schematic diagram of an active microphone control circuit according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It should be apparent that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated in a particular manner, and are not to be construed as limiting the present application. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.
In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be mechanically, electrically or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other suitable relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
The following disclosure provides many different embodiments or examples for implementing different features of the application. In order to simplify the disclosure of the present application, specific example components and arrangements are described below. Of course, they are merely examples and are not intended to limit the present application. Moreover, the present application may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, examples of various specific processes and materials are provided herein, but one of ordinary skill in the art may recognize applications of other processes and/or use of other materials. In some instances, methods, means, elements and circuits that are well known to those skilled in the art have not been described in detail so as not to obscure the present application.
The present application mainly provides an active microphone control circuit, the active microphone control circuit includes: the microphone input unit is used for acquiring an input first voice signal, wherein the first voice signal comprises a first differential signal and a second differential signal; the gain adjusting unit is electrically connected with the microphone input unit and is used for amplifying the first voice signal to obtain an amplified second voice signal; and the processing unit is electrically connected with the gain adjusting unit and is used for processing the second voice signal.
The microphone input unit is used for acquiring an input first voice signal comprising a first differential signal and a second differential signal, the gain adjusting unit is used for amplifying the first voice signal to obtain an amplified second voice signal, and the processing unit is used for processing the second voice signal.
Fig. 2 shows a block diagram of an active microphone control circuit of an embodiment of the present application.
As shown in fig. 2, the active microphone control circuit 1 includes: microphone input section 11, gain adjustment section 12, and processing section 13. The microphone input unit 11 is electrically connected to the gain adjusting unit 12, the gain adjusting unit is electrically connected to the microphone input unit 11 and the processing unit 13, and the processing unit 13 is electrically connected to the gain adjusting unit 12. The processing unit 13 may also be electrically connected to other circuitry outside for further processing of the processing unit's processing.
The microphone input unit is used for acquiring an input first voice signal, wherein the first voice signal comprises a first differential signal and a second differential signal. It is understood that there are various types of the first voice signal, and the input first voice signal is not limited in the present application.
Further, the gain adjustment unit is electrically connected to the microphone input unit and configured to amplify the first voice signal to obtain an amplified second voice signal.
Specifically, the gain adjustment unit includes an amplifier, and the amplifier includes a positive input end, a negative input end, and an output end, where the positive input end of the amplifier is configured to receive the first differential signal; the negative input end of the amplifier is used for receiving the second differential signal; the output end of the amplifier is electrically connected with the processing unit.
Wherein the amplifier may be an operational amplifier. In practical applications, the positions of the first differential signal and the second differential signal may also be interchanged, that is, the first differential signal may be connected to the negative input terminal of the amplifier, and the second differential signal may be connected to the positive input terminal of the amplifier. It is understood that the amplifier may be implemented in an integrated form or in a discrete device form, and the type of the amplifier is not limited in the present application.
Further, the gain adjustment unit further includes an amplifier peripheral circuit, where the amplifier peripheral circuit includes a first resistor, a first capacitor, a second resistor, and a second capacitor, where one end of the first capacitor is electrically connected to the first differential signal, the other end of the first capacitor is electrically connected to one end of the first resistor, and the other end of the first resistor is electrically connected to the positive input end of the amplifier; one end of the second capacitor is electrically connected to the second differential signal, the other end of the second capacitor is electrically connected to one end of the second resistor, and the other end of the second resistor is electrically connected to the positive input end of the amplifier.
Furthermore, the amplifier peripheral circuit further includes a third resistor and a third capacitor, where the third resistor and the third capacitor are connected in parallel, and one end of the third resistor and one end of the third capacitor are respectively electrically connected to the positive input end of the amplifier; the other end of the third resistor and the other end of the third capacitor are respectively grounded.
Further, the amplifier peripheral circuit further includes a fourth resistor and a fourth capacitor, where the fourth resistor and the fourth capacitor are connected in parallel, and one end of the fourth resistor and one end of the fourth capacitor are electrically connected to the negative input terminal of the amplifier, respectively; the other end of the fourth resistor and the other end of the fourth capacitor are electrically connected with the output end of the amplifier respectively.
Further, the gain of the gain adjusting unit is adjusted according to the first resistor, the second resistor, the third resistor and the fourth resistor. It is understood that the gain of the gain adjustment unit is related to the type of the amplifier and how the peripheral circuits of the amplifier are set, and the application is not limited to how the gain of the gain adjustment unit is calculated.
Furthermore, the active microphone control circuit further includes a fifth resistor, a fifth capacitor and a sixth capacitor, wherein one end of the fifth capacitor is electrically connected to the output end of the amplifier, the other end of the fifth capacitor is electrically connected to one end of the fifth capacitor, and the other end of the fifth capacitor is electrically connected to the processing unit; one end of the sixth capacitor is electrically connected with one end of the fifth capacitor, and the other end of the sixth capacitor is grounded.
Fig. 3 shows a block diagram of an active microphone control circuit of an embodiment of the present application.
As shown in fig. 3, the active microphone control circuit further comprises a single-ended adjustment unit 14. The single-ended adjustment unit may be electrically connected to an input of the gain adjustment unit and an output of the gain adjustment unit, respectively.
Specifically, the single-ended adjustment unit includes a sixth resistor and a seventh resistor, where one end of the sixth resistor is electrically connected to one end of the sixth capacitor, and the other end of the sixth resistor is grounded; one end of the seventh resistor is electrically connected with one end of the first capacitor, and the other end of the seventh resistor is electrically connected with one end of the sixth resistor.
By adding the circuit for converting the differential signal into the single-ended signal in the active microphone control circuit, the embodiment of the application can expand application scenes, is compatible with the design of the single-ended active microphone circuit, and meets diversified design requirements.
Fig. 4 shows a block diagram of an active microphone control circuit of an embodiment of the present application.
As shown in fig. 4, the active microphone interface circuit further includes a first diagnostic detection unit and a second diagnostic detection unit. The first diagnosis detection unit and the second diagnosis detection unit can be electrically connected with the input of the gain adjustment unit.
Specifically, the active microphone interface circuit further includes a first diagnosis detection unit, where the first diagnosis detection unit includes an eighth resistor, a ninth resistor, a tenth resistor, a seventh capacitor, an eighth capacitor, and a first processor, where one end of the eighth resistor is electrically connected to one end of the first capacitor, and the other end of the eighth resistor is electrically connected to one end of the ninth resistor, one end of the tenth resistor, and one end of the eighth capacitor, respectively; the other end of the tenth resistor and the other end of the eighth capacitor are grounded; the other end of the ninth resistor is electrically connected with one end of a seventh capacitor and the first processor respectively, and the other end of the seventh capacitor is grounded.
Further, the active microphone interface circuit further includes a second diagnosis detection unit, where the second diagnosis detection unit includes an eleventh resistor, a twelfth resistor, a thirteenth resistor, a ninth capacitor, a tenth capacitor, and a second processor, where one end of the eleventh resistor is electrically connected to one end of the second capacitor, and the other end of the eleventh resistor is electrically connected to one end of the thirteenth resistor, one end of the twelfth resistor, and one end of the tenth capacitor, respectively; the other end of the thirteenth resistor and the other end of the tenth capacitor are grounded; the other end of the twelfth resistor is electrically connected with one end of a ninth capacitor and the second processor respectively, and the other end of the ninth capacitor is grounded.
By utilizing double-path diagnosis and detection, the active microphone control circuit can improve the fault diagnosis efficiency and meet the requirement of active microphone fault diagnosis.
Further, the processing unit is electrically connected with the gain adjusting unit and is used for processing the second voice signal. The processing unit may further process the amplified second speech signal. It is to be understood that the present application is not limited to the processing unit.
The specific structure and operation of the active microphone control circuit will be described in conjunction with fig. 5.
Fig. 5 shows a schematic diagram of an active microphone control circuit of an embodiment of the present application.
As shown in fig. 5, the active microphone control circuit 1 of the embodiment of the present application may be provided in an IVI controller. The active Microphone control circuit 1 is electrically connected to a Microphone terminal (Mic-Connector) to receive a voice signal input from a Microphone (Mic). The voice signal may include a first differential signal in + and a second differential signal in-.
In + can be electrically connected with VCC through resistor R1, and in-can be electrically connected with GND through resistor R2. The resistance of the resistor R1 may be equal to the resistance of the resistor R2, for example, 330 ohms each. The resistor R1 and the resistor R2 can be used to make the microphone work at the working point of the middle voltage of 1/2VCC, and make the microphone work normally under the preset current.
Further, referring to fig. 5, the first differential signal in + and the second differential signal in-may be input into the Gain adjustment unit (i.e., Gain & FR Adjust), respectively, which may be used to Adjust the Gain and frequency response of the active microphone signal. FR may be an abbreviation for Frequency Response, indicating Frequency Response.
Further, referring to fig. 5, the gain adjustment unit may include an amplifier U2, a first resistor R11, a second resistor R12, a third resistor R13, a fourth resistor R15, a first capacitor C1, a second capacitor C2, a third capacitor C3, and a fourth capacitor C4.
One end of the first capacitor C1 is used for receiving the first differential signal in +, and the other end of the first capacitor C1 is electrically connected with the first resistor R11; one end of the second capacitor C2 is used for receiving the second differential signal in-, and the other end of the second capacitor C2 is electrically connected with the second resistor R12. The capacitance of the first capacitor C1 and the capacitance of the second capacitor C2 may both be 2.2 uF.
Further, in fig. 5, one end of the first resistor R11 is electrically connected to the first capacitor C1, and the other end of the first resistor R11 is electrically connected to the positive input terminal of the amplifier, one end of the third resistor R13, and one end of the third capacitor C3, respectively; the other end of the third resistor R13 and the other end of the third capacitor C3 are both electrically connected to a predetermined voltage value (e.g., 1/2 VCC). The third resistor R13 may have a value of 12k ohms; the capacitance of the third capacitor C3 may be 100 pF.
Further, in fig. 5, one end of the second resistor R12 is electrically connected to the second capacitor C2, and the other end of the second resistor R12 is electrically connected to the negative input terminal of the amplifier, one end of the fourth capacitor C4, and one end of the fourth resistor R15, respectively; the other terminal of the fourth capacitor C4 and the other terminal of the fourth resistor R15 may be electrically connected to the output terminal of the amplifier (i.e., OUT). The capacitance of the fourth capacitor C4 may be 100pF, and the resistance of the fourth resistor R15 may be 12k ohms.
Further, the resistance of the first resistor R11 and the resistance of the second resistor R12 may be 22k ohms. The V + side of the amplifier may be connected to a power supply VCC, and the V-side of the amplifier may be connected to ground.
Further, an output of the amplifier may be electrically connected to one end of a fifth resistor R16, the other end of the fifth resistor R16 may be electrically connected to one end of a fifth capacitor C5, and the other end of the fifth capacitor C5 may be electrically connected to a processing unit (e.g., DSP). The resistance of the fifth resistor R16 may be 1k ohms, and the capacitance of the fifth capacitor C5 may be 0.47 uF. In addition, a sixth capacitor C8 may be further disposed on the output side of the gain adjustment unit, one end of the sixth capacitor C8 may be electrically connected to one end of the fifth capacitor C5, the other end of the sixth capacitor C8 may be grounded, and the capacitance value of the sixth capacitor C8 may be 10 nF.
Illustratively, the gain (i.e., amplification factor) of the gain adjustment unit may be calculated by the following formula:
Enlargement=[R13/(R13+R11)]*[(R15+R12)/R12]
wherein, the energy is the gain of the gain adjusting unit.
Further, referring to fig. 5, the Single-ended adjustment unit (Single-End Gain Adjust) may include a sixth resistor R17 and a seventh resistor R18. One end of the sixth resistor R17 may be electrically connected to one end of the sixth capacitor C8, and the other end of the sixth resistor R17 may be grounded; one end of the seventh resistor R18 may be electrically connected to one end of the first capacitor C1, and the other end of the seventh resistor R18 may be electrically connected to one end of the fifth capacitor C5. It should be noted that, in practical applications, the sixth resistor R17 and the seventh resistor R18 may Not be mounted (i.e., Not Mount, NM) as required.
For example, the single-ended gain of the single-ended adjustment unit can be calculated by the following formula:
Gain=[(Vmic+)-(Vmic-)]*Enlargement
wherein Gain is single-ended Gain; enlargement is the gain of the gain adjustment unit; vmic + is the first differential signal and Vmic-is the second differential signal.
In practical applications, the single-ended gain and the gain of the gain adjustment unit may be adjusted according to the processing capability of the back-end processing unit. For example, the processing unit is a DSP, and the maximum amplitude of the analog voltage at the input of the DSP is currently 1Vrms or 0.6Vrms, and further processing can be performed as long as the active microphone signal does not exceed this amplitude limit.
When a differential circuit is used, the resistors R17 and R18 of this circuit may be non-mounted (NM). If the system needs to be accessed by using a single-ended active microphone, the two resistors are mounted, the resistor R1 is changed to 680 ohms, the resistor R2 is changed to 0 ohms, and the former Gain & FR Adjust circuit is NM. Therefore, the gain of the single-ended audio signal is adjusted through the resistor R17 and the resistor R18, and when an active microphone is used, the gain can be adjusted to be smaller, because the sensitivity of the active microphone is generally very large, and therefore, in order to meet the amplitude limit of the analog signal processed by the back-end DSP, attenuation processing is usually performed before the analog signal enters the DSP.
Further, referring to fig. 5, the first diagnostic detection unit (i.e., ADC-DET 1) may include an eighth resistor R7, a ninth resistor R5, a tenth resistor R8, a seventh capacitor C7, an eighth capacitor C9, and a processor MCU. One end of the eighth resistor R7 may be electrically connected to one end of the first capacitor for receiving the first differential signal in +, and the other end of the eighth resistor R7 may be electrically connected to one end of the ninth resistor R5, one end of the tenth resistor R8, and one end of the eighth capacitor C9, respectively; the other end of the tenth resistor R8 and the other end of the eighth capacitor C9 may be grounded; the other end of the ninth resistor R5 may be electrically connected to one end of the seventh capacitor C7 and the input pin of the MCU (i.e., AD1 DET), respectively, and the other end of the seventh capacitor C7 may be grounded.
The resistance of the eighth resistor R7 may be 30k ohms, the resistance of the ninth resistor R5 may be 20k ohms, the resistance of the tenth resistor R8 may be 4.7k ohms, the capacitance of the seventh capacitor C7 may be 1nF, and the capacitance of the eighth capacitor C9 may be 10 nF.
Further, referring to fig. 5, the second diagnostic detection unit (i.e., ADC-DET 2) may include an eleventh resistor R9, a twelfth resistor R14, a thirteenth resistor R10, a ninth capacitor C6, a tenth capacitor C10, and a processor MCU. One end of the eleventh resistor R9 may be electrically connected to one end of the second capacitor for receiving the second differential signal in —, and the other end of the eleventh resistor R9 may be electrically connected to one end of the thirteenth resistor R10, one end of the twelfth resistor R14, and one end of the tenth capacitor C10, respectively; the other end of the thirteenth resistor R10 and the other end of the tenth capacitor C10 may be grounded; the other end of the twelfth resistor R14 may be electrically connected to one end of the ninth capacitor C6 and the input pin of the MCU (i.e., AD2 DET), respectively, and the other end of the ninth capacitor C6 may be grounded.
The value of the eleventh resistor R9 may be 27k ohms, the value of the twelfth resistor R14 may be 20k ohms, the value of the thirteenth resistor R10 may be 3.3k ohms, the capacitance of the ninth capacitor C6 may be 1nF, and the capacitance of the tenth capacitor C10 may be 10 nF.
For example, the ADC voltage received by the first processor may be calculated using the following equation:
ADC1=(VDCin+)*[R8/(R7+R8)]
the ADC voltage received by the second processor may be calculated using the following equation:
ADC2=(VDCin-)*[R10/(R9+R10)]
in one example, in operation, reference is made to circuitry of the diagnostic test portion. When the source microphone is normally connected, the "+" end of the voice differential signal from the socket can be divided by resistors R7 and R8, and enters an ADC (Analog-to-Digital Converter) terminal of the MCU for calculation through a current-limiting resistor R5. And judging the state of the socket of the current active microphone according to the calculated voltage amplitude. Similarly, the "-" end of the voice differential signal coming from the socket is divided by resistors R9 and R10, and enters the ADC terminal of the MCU through a current-limiting resistor R14 for calculation. The capacitors C7, C9, C10 and C6 play roles in filtering and resisting disturbance. The state of the socket of the current active microphone can be judged according to the calculated voltage amplitude. The ADC diagnostic voltage can be referenced as follows:
the two connector terminals of the active microphone are subjected to open circuit and short circuit detection, and two ADC sampling circuits are used for adopting different ADC values to realize fault detection. In application, a user can be prompted about the current 2 terminal states of the active microphone according to different ADC values, and the 2 terminal states of the active microphone can also be judged by combining two ADC values.
It should be noted that the MCU in the first diagnostic detection unit and the MCU in the second diagnostic detection unit may be the same MCU or different MCUs, which is not limited in this application.
Fig. 6 is a schematic diagram illustrating the amplitude of the output signal of the gain adjustment unit according to the embodiment of the present application.
As shown in fig. 6, the horizontal axis represents Time (i.e., Time) and the vertical axis represents voltage value. Wherein, V (IN +) is the voltage of the differential signal IN +, V (IN-) is the voltage of the differential signal IN-, and OUT is the voltage output by the gain adjustment unit. When the sensitivity of the active microphone is-3.5 dB, the differential signal is input, and the waveform input to the DSP can be obtained through adjustment by the gain adjustment unit. As can be seen from fig. 6, the waveform satisfies the input amplitude limit of the DSP. In practical application, if the input amplitude exceeds the input limit value of the DSP after being calculated by the formula, the resistance in the Enlargement formula can be properly adjusted.
Fig. 7 shows a frequency response schematic diagram of an active microphone control circuit according to an embodiment of the present application.
As shown in fig. 7, the horizontal axis represents Frequency (i.e., Frequency) and the vertical axis represents gain. The gain can be calculated by the formula 20 × Log10[ V (out)/(V (in +) -V (in-) ]. Further, the frequency response at the high frequency of the voice signal can be adjusted by adjusting the values of C3, C4, C8, and the frequency response at the low frequency of the voice signal can be adjusted by adjusting the values of C1, C2, C5. As can be seen from FIG. 7, the actual frequency response meets the 100-10KHz (. + -. 3 dB) frequency response requirement.
By adjusting the frequency response of the single-ended signal after the differential signal is converted into the single-ended signal, the signal output by the embodiment of the application can be more convenient for a rear-end processing unit to process, and the processing efficiency of the voice signal is improved.
To sum up, this application embodiment obtains the first speech signal of input including first difference signal and second difference signal through utilizing microphone input unit to it is right to utilize gain adjustment unit first speech signal enlargies and obtains the second speech signal after enlargiing, and it is right to recycle processing unit the second speech signal is handled, and this application can realize the adjustment to the gain before the speech signal processing, is favorable to the processing unit of rear end to handle more conveniently, improves speech signal's treatment effeciency.
In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
The active microphone control circuit provided in the embodiments of the present application is described in detail above, and the principles and embodiments of the present application are explained herein by applying specific examples, and the description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application; those of ordinary skill in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications or substitutions do not depart from the spirit and scope of the present disclosure as defined by the appended claims.
Claims (9)
1. An active microphone control circuit, comprising:
the microphone input unit is used for acquiring an input first voice signal, wherein the first voice signal comprises a first differential signal and a second differential signal;
the gain adjusting unit is electrically connected with the microphone input unit and used for amplifying the first voice signal to obtain an amplified second voice signal, and the gain adjusting unit comprises an amplifier;
the processing unit is electrically connected with the gain adjusting unit and is used for processing the second voice signal;
the active microphone control circuit further comprises a fifth resistor, a fifth capacitor and a sixth capacitor, wherein one end of the fifth resistor is electrically connected with the output end of the amplifier, the other end of the fifth resistor is electrically connected with one end of the fifth capacitor, and the other end of the fifth capacitor is electrically connected with the processing unit; one end of the sixth capacitor is electrically connected with one end of the fifth capacitor, and the other end of the sixth capacitor is grounded.
2. The active microphone control circuit of claim 1, wherein the amplifier comprises a positive input terminal, a negative input terminal, and an output terminal, wherein,
a positive input of the amplifier is configured to receive the first differential signal; the negative input end of the amplifier is used for receiving the second differential signal; the output end of the amplifier is electrically connected with the processing unit.
3. The active microphone control circuit of claim 2, wherein the gain adjustment unit further comprises an amplifier peripheral circuit comprising a first resistor, a first capacitor, a second resistor, a second capacitor, wherein,
one end of the first capacitor is electrically connected to the first differential signal, the other end of the first capacitor is electrically connected to one end of the first resistor, and the other end of the first resistor is electrically connected to the positive input end of the amplifier;
one end of the second capacitor is electrically connected to the second differential signal, the other end of the second capacitor is electrically connected to one end of the second resistor, and the other end of the second resistor is electrically connected to the positive input end of the amplifier.
4. The active microphone control circuit of claim 3, wherein the amplifier peripheral circuit further comprises a third resistor and a third capacitor, the third resistor connected in parallel with the third capacitor, wherein,
one end of the third resistor and one end of the third capacitor are respectively electrically connected with the positive input end of the amplifier;
the other end of the third resistor and the other end of the third capacitor are respectively and electrically connected to a preset voltage value.
5. The active microphone control circuit of claim 4, wherein the amplifier peripheral circuit further comprises a fourth resistor and a fourth capacitor, the fourth resistor being connected in parallel with the fourth capacitor, wherein,
one end of the fourth resistor and one end of the fourth capacitor are respectively electrically connected with the negative input end of the amplifier;
the other end of the fourth resistor and the other end of the fourth capacitor are electrically connected with the output end of the amplifier respectively.
6. The active microphone control circuit of claim 5, wherein the gain of the gain adjustment unit is adjusted based on the first resistor, the second resistor, the third resistor, and the fourth resistor.
7. The active microphone control circuit of claim 6, further comprising a single-ended adjustment unit comprising a sixth resistance and a seventh resistance, wherein,
one end of the sixth resistor is electrically connected with one end of the sixth capacitor, and the other end of the sixth resistor is grounded; one end of the seventh resistor is electrically connected with one end of the first capacitor, and the other end of the seventh resistor is electrically connected with one end of the sixth resistor.
8. The active microphone control circuit of claim 7, further comprising a first diagnostic detection unit comprising an eighth resistor, a ninth resistor, a tenth resistor, a seventh capacitor, an eighth capacitor, and a first processor, wherein,
one end of the eighth resistor is electrically connected with one end of the first capacitor, and the other end of the eighth resistor is electrically connected with one end of the ninth resistor, one end of the tenth resistor and one end of the eighth capacitor respectively;
the other end of the tenth resistor and the other end of the eighth capacitor are grounded; the other end of the ninth resistor is electrically connected with one end of a seventh capacitor and the first processor respectively, and the other end of the seventh capacitor is grounded.
9. The active microphone control circuit of claim 7, further comprising a second diagnostic detection unit comprising an eleventh resistor, a twelfth resistor, a thirteenth resistor, a ninth capacitor, a tenth capacitor, and a second processor, wherein,
one end of the eleventh resistor is electrically connected with one end of the second capacitor, and the other end of the eleventh resistor is electrically connected with one end of the thirteenth resistor, one end of the twelfth resistor and one end of the tenth capacitor respectively;
the other end of the thirteenth resistor and the other end of the tenth capacitor are grounded; the other end of the twelfth resistor is electrically connected with one end of a ninth capacitor and the second processor respectively, and the other end of the ninth capacitor is grounded.
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| CN103380570A (en) * | 2010-11-15 | 2013-10-30 | 意法爱立信有限公司 | Interface circuit for connecting a microphone circuit to a preamplifier. |
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| KR100258218B1 (en) * | 1997-12-31 | 2000-06-01 | 윤종용 | Apparatus and method for connecting plug |
| CN101064875A (en) * | 2006-04-27 | 2007-10-31 | 叶波 | Vehicle-mounted handfree communication chip |
| CN101662712B (en) * | 2008-08-28 | 2014-04-30 | 深圳富泰宏精密工业有限公司 | Microphone circuit |
| CN101841588B (en) * | 2009-03-17 | 2014-04-30 | 深圳富泰宏精密工业有限公司 | Audio interface device and electronic device using same |
| CN102448007A (en) * | 2011-12-21 | 2012-05-09 | 上海博泰悦臻电子设备制造有限公司 | Microphone diagnosis circuit |
| CN203872342U (en) * | 2014-04-25 | 2014-10-08 | 比亚迪股份有限公司 | Sound acquiring device and vehicle with sound acquiring device |
| CN212969578U (en) * | 2020-08-07 | 2021-04-13 | 北京罗克维尔斯科技有限公司 | Audio signal amplifying circuit and vehicle |
| CN212726952U (en) * | 2020-08-18 | 2021-03-16 | 珠海格力电器股份有限公司 | Amplifying circuit for converting microphone differential input into single-ended output |
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| CN103380570A (en) * | 2010-11-15 | 2013-10-30 | 意法爱立信有限公司 | Interface circuit for connecting a microphone circuit to a preamplifier. |
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