CN116546388A - Echo cancellation circuit and audio device - Google Patents
Echo cancellation circuit and audio device Download PDFInfo
- Publication number
- CN116546388A CN116546388A CN202310363401.2A CN202310363401A CN116546388A CN 116546388 A CN116546388 A CN 116546388A CN 202310363401 A CN202310363401 A CN 202310363401A CN 116546388 A CN116546388 A CN 116546388A
- Authority
- CN
- China
- Prior art keywords
- circuit
- digital
- analog
- audio signal
- audio
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000006243 chemical reaction Methods 0.000 claims abstract description 102
- 238000005070 sampling Methods 0.000 claims abstract description 45
- 238000000605 extraction Methods 0.000 claims abstract description 44
- 230000005236 sound signal Effects 0.000 claims description 210
- 239000003990 capacitor Substances 0.000 claims description 42
- 238000001914 filtration Methods 0.000 claims description 10
- 238000010586 diagram Methods 0.000 description 16
- 238000000034 method Methods 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- 238000004891 communication Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 101000576901 Homo sapiens Serine/threonine-protein kinase MRCK alpha Proteins 0.000 description 1
- 102100025352 Serine/threonine-protein kinase MRCK alpha Human genes 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2430/00—Signal processing covered by H04R, not provided for in its groups
-
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- 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
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
The application provides an echo cancellation circuit and audio equipment, and belongs to the technical field of audio processing. The echo cancellation circuit includes: the device comprises an audio sampling circuit, a first analog-to-digital conversion circuit, an audio extraction circuit, a second analog-to-digital conversion circuit and a digital signal processor; the input end of the audio sampling circuit is connected with the microphone, and the output end of the audio sampling circuit is connected with the input end of the first analog-to-digital conversion circuit; the output end of the first analog-to-digital conversion circuit is connected with the input end of the digital signal processor; the input end of the audio extraction circuit is connected with the loudspeaker, and the output end of the audio extraction circuit is connected with the input end of the second analog-to-digital conversion circuit; the output end of the second analog-to-digital conversion circuit is connected with the input end of the digital signal processor; the output end of the digital signal processor is connected with the loudspeaker. The echo cancellation circuit can avoid the interference of the echo signal to the voice and improve the user experience.
Description
Technical Field
The present disclosure relates to the field of audio processing technologies, and in particular, to an echo cancellation circuit and an audio device.
Background
Currently, electronic devices having functions of voice communication, video communication, voice input, etc. have been widely used in the work and life of people. Such as a cell phone, tablet computer, intelligent center screen, etc. Because the microphone and the loudspeaker are arranged in the electronic equipment, in the process of collecting the audio signals by the microphone, not only the audio signals (human voice) sent by the user but also the audio signals (echo signals) played by the loudspeaker are collected, so that the human voice captured by the microphone is interfered by the echo signals, and the use experience of the user is affected. Therefore, there is an urgent need for an echo cancellation circuit capable of avoiding the echo signal from interfering with the human voice.
Disclosure of Invention
The embodiment of the application provides an echo cancellation circuit and audio equipment, which can avoid the interference of echo signals on human voice and improve user experience. The technical scheme is as follows:
in one aspect, there is provided an echo cancellation circuit comprising: the device comprises an audio sampling circuit, a first analog-to-digital conversion circuit, an audio extraction circuit, a second analog-to-digital conversion circuit and a digital signal processor;
the input end of the audio sampling circuit is connected with a microphone, the output end of the audio sampling circuit is connected with the input end of the first analog-to-digital conversion circuit, the audio sampling circuit is used for sampling a first audio signal acquired at the current moment of the microphone, and the first analog-to-digital conversion circuit is used for carrying out analog-to-digital conversion on the sampled first audio signal to obtain a digital audio signal of the first audio signal;
the output end of the first analog-to-digital conversion circuit is connected with the input end of the digital signal processor;
the input end of the audio extraction circuit is connected with a loudspeaker, the output end of the audio extraction circuit is connected with the input end of the second analog-to-digital conversion circuit, the audio extraction circuit is used for sampling a second audio signal output at the last moment of the loudspeaker, and the second analog-to-digital conversion circuit is used for carrying out analog-to-digital conversion on the sampled second audio signal to obtain a digital audio signal of the second audio signal;
The output end of the second analog-to-digital conversion circuit is connected with the input end of the digital signal processor;
the output end of the digital signal processor is connected with the loudspeaker, the digital signal processor is used for carrying out echo cancellation on the first audio signal based on the digital audio signal of the first audio signal and the digital audio signal of the second audio signal, and the loudspeaker is used for playing the first audio signal after echo cancellation.
In some embodiments, the audio sampling circuit includes a first differential input, a second differential input, a first differential output, and a second differential output;
the first differential input end and the second differential input end are respectively connected with the first end and the second end of the microphone;
the first differential output end and the second differential output end are respectively connected with the first input end and the second input end of the first analog-to-digital conversion circuit.
In some embodiments, the audio sampling circuit further comprises a first power supply terminal, a first ground terminal, a second ground terminal, a first power supply circuit, a first static protection circuit, a first filter circuit, a first resistor, and a second resistor;
The first end of the first power supply circuit is connected with the first power supply end, the second end of the first power supply circuit is connected with the first end of the first resistor, the third end of the first power supply circuit is connected with the first grounding end, and the first power supply circuit is used for supplying power to the microphone;
the first end and the second end of the first electrostatic protection circuit are respectively connected with the first differential input end and the second differential input end, the third end of the first electrostatic protection circuit is connected with the second grounding end, and the first electrostatic protection circuit is used for carrying out electrostatic protection on the microphone;
the first end and the second end of the first filter circuit are respectively connected with the first differential input end and the second differential input end, the third end and the fourth end of the first filter circuit are respectively connected with the first differential output end and the second differential output end, and the first filter circuit is used for filtering the first audio signal;
the second end of the first resistor is connected with the first differential input end, and the first resistor is used for providing bias voltage for the microphone;
the first end of the second resistor is connected with the second differential input end, the second end of the second resistor is connected with the second grounding end, and the second resistor is used for providing bias voltage for the microphone.
In some embodiments, the audio extraction circuit includes a first differential input, a second differential input, a first differential output, and a second differential output;
the first differential input end and the second differential input end are respectively connected with the first end and the second end of the loudspeaker;
the first differential output end and the second differential output end are respectively connected with a first input end and a second input end of the second analog-to-digital conversion circuit.
In some embodiments, the audio extraction circuit further comprises a third ground terminal, a second electrostatic protection circuit, a resistive voltage division circuit, and a second filter circuit;
the first end and the second end of the second electrostatic protection circuit are respectively connected with the first differential input end and the second differential input end of the audio extraction circuit, the third end of the second electrostatic protection circuit is connected with the third grounding end, and the second electrostatic protection circuit is used for carrying out electrostatic protection on the loudspeaker;
the first end and the second end of the resistor divider circuit are respectively connected with the first differential input end and the second differential input end of the audio extraction circuit, the third end and the fourth end of the resistor divider circuit are respectively connected with the first end and the second end of the second filter circuit, the fifth end of the resistor divider circuit is connected with the third grounding end, the resistor divider circuit is used for dividing the voltage between the first differential input end and the second differential input end of the audio extraction circuit, and the second filter circuit is used for filtering the second audio signal;
And a third end and a fourth end of the second filter circuit are respectively connected with a first differential output end and a second differential output end of the audio extraction circuit, and a fifth end of the second filter circuit is connected with the third grounding end.
In some embodiments, the second analog-to-digital conversion circuit includes a second power supply terminal, a fourth ground terminal, a second power supply circuit, and an analog-to-digital converter;
the first end of the second power supply circuit is connected with the second power supply end, the second end of the second power supply circuit is connected with the power supply end of the analog-to-digital converter, the third end of the second power supply circuit is connected with the fourth grounding end, the second power supply circuit is used for supplying power to the analog-to-digital converter, and the analog-to-digital converter is used for carrying out analog-to-digital conversion on the sampled second audio signal to obtain a digital audio signal of the second audio signal;
the first input end and the second input end of the analog-to-digital converter are respectively connected with the first differential output end and the second differential output end of the audio extraction circuit, and the output end of the analog-to-digital converter is connected with the output end of the second analog-to-digital conversion circuit.
In some embodiments, the digital signal processor includes a signal processing circuit and a digital-to-analog conversion circuit;
The input end of the signal processing circuit is connected with the output end of the first analog-to-digital conversion circuit, the input end of the signal processing circuit is connected with the output end of the second analog-to-digital conversion circuit, the output end of the signal processing circuit is connected with the input end of the digital-to-analog conversion circuit, the signal processing circuit is used for carrying out echo cancellation on the digital audio signal of the first audio signal based on the digital audio signal of the second audio signal, and the digital-to-analog conversion circuit is used for carrying out digital-to-analog conversion on the digital audio signal after echo cancellation to obtain the first audio signal after echo cancellation;
the output end of the digital-to-analog conversion circuit is connected with the loudspeaker.
In another aspect, an audio device is provided that includes the echo cancellation circuit described above, a microphone, and a speaker.
The embodiment of the application provides an echo cancellation circuit, which can sample a first audio signal acquired at the current moment of a microphone and a second audio signal output at the last moment of a loudspeaker through an audio sampling circuit and an audio extraction circuit, and then perform analog-to-digital conversion on the sampled audio signals through a first analog-to-digital conversion circuit and a second analog-to-digital conversion circuit, so that respective digital audio signals can be obtained. The digital signal processor processes the respective digital audio signals, and the echo cancellation can be performed on the first audio signal by comparing the digital audio signal of the first audio signal with the digital audio signal of the second audio signal, i.e. the echo signal in the first audio signal which is identical to the second audio signal is cancelled. The interference of the echo signals to the human voice is avoided, and the user experience is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that 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 an echo cancellation circuit according to an embodiment of the present application;
fig. 2 is a schematic diagram of an audio sampling circuit according to an embodiment of the present application;
FIG. 3 is a schematic diagram of another audio sampling circuit provided in an embodiment of the present application;
fig. 4 is a schematic diagram of an audio extraction circuit according to an embodiment of the present disclosure;
FIG. 5 is a schematic diagram of another audio extraction circuit provided in an embodiment of the present application;
fig. 6 is a schematic diagram of a second analog-to-digital conversion circuit according to an embodiment of the present application;
FIG. 7 is a schematic diagram of a digital signal processor according to an embodiment of the present application;
fig. 8 is a schematic diagram of an audio amplifying circuit according to an embodiment of the present application.
Reference numerals denote:
an audio sampling circuit-10, a first differential input end-10 a, a second differential input end-10 b, a first differential output end-10 c, a first differential output end-10 d
First power supply circuit-10, third resistor-101 a, first capacitor-101 b, second capacitor-101 c
First electrostatic protection circuit-102, first transistor-102 a, second transistor-102 b
First filter circuit-103, third capacitor-103 a, fourth capacitor-103 b
First resistor-104
Second resistor-105
First analog-to-digital conversion circuit-20
An audio extraction circuit-20, a first differential input end-30 a, a second differential input end-30 b, a first differential output end-30 c and a second differential output end-30 d
Second electrostatic protection circuit-301, third transistor-301 a, fourth transistor-301 b
Resistor divider circuit-302, fourth resistor-302 a, fifth resistor-302 b, sixth resistor-302 c, seventh resistor-302 d
A second filter circuit-303, an eighth resistor-303 a, a fifth capacitor-303 b, a sixth capacitor-303 c, a ninth resistor-303 d, a seventh capacitor-303 e, and an eighth capacitor-303 f
Second analog-to-digital conversion circuit-40
Second power supply circuit-401, analog-to-digital converter-402
Digital signal processor-50
Signal processing circuit-501, digital-to-analog conversion circuit-502
Audio amplifying circuit-60
Signal conversion circuit-601, audio amplifier-602, third power supply circuit-603
A first power supply end-A1, a first grounding end-A2, a second grounding end-A3, a third grounding end-A4, a second power supply end-A5, a fourth grounding end-A6, a third power supply end-A7 and a fifth grounding end-A8
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the embodiments of the present application will be described in further detail below with reference to the accompanying drawings.
The embodiment of the application provides an echo cancellation circuit, which can avoid the interference of echo signals on human voice and improve user experience.
Fig. 1 is a schematic diagram of an echo cancellation circuit according to an embodiment of the present application. Referring to fig. 1, the echo cancellation circuit includes: an audio sampling circuit 10, a first analog-to-digital conversion circuit 20, an audio extraction circuit 30, a second analog-to-digital converter 40, and a digital signal processor 50.
An input end of the audio sampling circuit 10 is connected with a microphone, an output end of the audio sampling circuit 10 is connected with an input end of the first analog-to-digital conversion circuit 20, and an output end of the first analog-to-digital conversion circuit 20 is connected with an input end of the digital signal processor 50. The audio sampling circuit 10 is configured to sample a first audio signal collected at a current moment of the microphone, and the first analog-to-digital conversion circuit 20 is configured to perform analog-to-digital conversion on the sampled first audio signal, so as to obtain a digital audio signal of the first audio signal. The microphone is used for converting collected sound signals into electric signals, the first audio signals are electric signals obtained by converting the collected sound signals at the current moment of the microphone, and the first audio signals are analog signals. Since the digital signal processor 50 cannot directly process the analog signal, the first audio signal needs to be sampled by the audio sampling circuit 10 before being input to the digital signal processor 50, and then converted from the analog signal to the digital signal by the first analog-to-digital conversion circuit 20, so that the voice information in the first audio signal can be processed based on the digital signal processor 50. After the digital signal processor 50 processes the digital audio signal of the first audio signal, the processed first audio signal can be input to a speaker, and the audio signal can be played by the speaker.
The input end of the audio extraction circuit 30 is connected with a loudspeaker, the output end of the audio extraction circuit 30 is connected with the input end of the second analog-to-digital conversion circuit 40, the audio extraction circuit 30 is used for sampling a second audio signal output by the loudspeaker at the last moment, and the second analog-to-digital conversion circuit 40 is used for performing analog-to-digital conversion on the sampled second audio signal to obtain a digital audio signal of the second audio signal. An output of the second analog to digital conversion circuit 40 is connected to an input of the digital signal processor 50. The loudspeaker is used for converting an electric signal (audio signal) into a sound signal and playing the sound signal for a user to listen. The audio sampling circuit 10 and the first analog-to-digital conversion circuit 20 can process the audio signal acquired by the microphone at the previous time before the speaker outputs the second audio signal, and input the processed digital audio signal to the digital signal processor 50. After processing the digital audio signal, the digital signal processor 50 can input the processed second audio signal to a speaker, and play the second audio signal by the speaker. The second audio signal is an analog signal. Since the digital signal processor 50 cannot directly process the analog signal, the first audio signal needs to be sampled by the audio extraction circuit 30 before the second audio signal output from the speaker is input to the digital signal processor 50, and then the second audio signal is converted from the analog signal to the digital signal by the second analog-to-digital conversion circuit 40, so that the voice information in the second audio signal can be processed based on the digital signal processor 50.
The output end of the digital signal processor 50 is connected to a speaker, the digital signal processor 50 is configured to perform echo cancellation on the first audio signal based on the digital audio signal of the first audio signal and the digital audio signal of the second audio signal, and the speaker is configured to play the echo cancelled first audio signal. In the process of collecting the audio signals by the microphone, not only the sound signals sent by the user but also the audio signals output by the loudspeaker can be collected. Therefore, the first audio signal collected at the current moment comprises the sound signal sent by the user at the current moment and part of the audio signal output by the loudspeaker, namely the sound signal sent by the user at the last moment. Since the second audio signal is an audio signal output from the speaker at a previous time, including a sound signal generated by the user at the previous time, the first audio signal includes a part of the second audio signal. The digital signal processor 50 can obtain the voice information of the first audio signal and the voice information of the second audio signal by processing the digital audio signal of the first audio signal and the digital audio signal of the second audio signal. The digital signal processor 50 is capable of canceling the same voice information in the first audio signal as the voice information in the second audio signal, that is, canceling the echo signal in the first audio signal, which is the audio signal collected by the microphone from the speaker, by comparing the voice information in the first audio signal with the voice information in the second audio signal. Since the output end of the digital signal processor 50 is connected to the speaker, the digital signal processor 50 can input the first audio signal after echo cancellation to the speaker and play the first audio signal by the speaker.
In some embodiments, the audio sampling circuit 10 includes two differential inputs and two differential outputs. Fig. 2 is a schematic diagram of an audio sampling circuit according to an embodiment of the present application. Referring to fig. 2, the audio sampling circuit 10 includes a first differential input terminal 10a, a second differential input terminal 10b, a first differential output terminal 10c, and a second differential output terminal 10d. The first and second differential inputs 10a and 10b are connected to the first and second ends of the microphone, respectively. The first differential output terminal 10c and the second differential output terminal 10d are connected to a first input terminal and a second input terminal of the first analog-to-digital conversion circuit 20, respectively. The first differential input terminal 10a and the second differential input terminal 10b can perform differential transmission on the first audio signal collected by the microphone. The audio signal input by the first differential input terminal 10a and the audio signal input by the second differential input terminal 10b are differential signals, and the amplitudes of the two signals are the same and the phases are opposite. Similarly, the first differential output terminal 10c and the second differential output terminal 10d are capable of differentially transmitting the sampled first audio signal. The audio signal output by the first differential output terminal 10c and the audio signal input by the second differential output terminal 10d are differential signals, and the amplitudes of the two signals are the same and the phases are opposite. The audio sampling circuit 10 can input the sampled first audio signal to the first analog-to-digital conversion circuit 20 through the first differential output terminal 10c and the second differential output terminal 10d, and the first analog-to-digital conversion circuit 20 can convert the sampled first audio signal into a digital audio signal. The first analog-to-digital conversion circuit 20 inputs the digital audio signal to the digital signal processor 50 through an output terminal, and the digital audio signal of the first audio signal is processed by the digital signal processor 50.
In some embodiments, the microphone is a two-way microphone, including two independent microphones, namely a first microphone and a second microphone. The first microphone is connected to the input end of the first audio sampling circuit, the second microphone is connected to the input end of the second audio sampling circuit, and the output end of the first audio sampling circuit and the output end of the second audio sampling circuit are connected to the input end of the first analog-to-digital conversion circuit 20. The circuit configuration of the first audio sampling circuit and the second audio sampling circuit is the same as that of the audio sampling circuit 10.
In some embodiments, the audio sampling circuit 10 further includes an electrostatic protection circuit, a power supply circuit, and a filtering circuit. Fig. 3 is a schematic diagram of another audio sampling circuit according to an embodiment of the present application. Referring to fig. 3, the audio sampling circuit 10 further includes a first power source terminal A1, a first ground terminal A2, a second ground terminal A3, a first power supply circuit 101, a first electrostatic protection circuit 102, a first filter circuit 103, a first resistor 104, and a second resistor 105. The first end of the first power supply circuit 101 is connected to the first power supply terminal A1, the second end of the first power supply circuit 101 is connected to the first end of the first resistor 104, and the third end of the first power supply circuit 101 is connected to the first ground terminal A2. The first end and the second end of the first electrostatic protection circuit 102 are respectively connected to the first differential input terminal 10a and the second differential input terminal 10b, and the third end of the first electrostatic protection circuit 102 is connected to the second ground terminal A3. The first and second ends of the first filter circuit 103 are connected to the first and second differential input terminals 10c and 10d, respectively, and the third and fourth ends of the first filter circuit 103 are connected to the first and second differential output terminals 10c and 10d, respectively. The second end of the first resistor 104 is connected to the first differential input terminal 10a, the first end of the second resistor 105 is connected to the second differential input terminal 10b, and the second end of the second resistor 105 is connected to the second ground terminal A3. The voltage provided by the first power supply terminal A1 may be any voltage in the working voltage range of the microphone, which is not limited in the embodiment of the present application. The first power supply circuit 101 is for supplying power to the microphone. The first electrostatic protection circuit 102 is used for electrostatic protection of the microphone to protect the microphone from electrostatic discharge. The first filter circuit 103 is configured to filter the first audio signal; the first resistor 104 and the second resistor 105 are used to provide a bias voltage to the microphone to enable the microphone to function properly.
In some embodiments, with continued reference to fig. 3, the first power supply circuit 101 is formed by combining a third resistor 101a, a first capacitor 101b, and a second capacitor 101 c. The first end of the third resistor 101a and the first end of the first capacitor 101b are connected to the first end of the first power supply circuit 101, the second end of the third resistor 101a and the first end of the second capacitor 101c are connected to the second end of the first power supply circuit 101, and the second end of the first capacitor 101b and the second end of the second capacitor 101c are connected to the third end of the first power supply circuit 101. The third resistor 101a, the first capacitor 101b, and the second capacitor 101c are used for filtering the power signal in the circuit, so as to improve the quality of the power signal and improve the stability of the power signal.
In some embodiments, with continued reference to fig. 3, the first esd protection circuit 102 is formed by combining a first transistor 102a and a second transistor 102 b. The first end of the first transistor 102a is connected to the first end of the first electrostatic protection circuit, the first end of the second transistor 102b is connected to the second end of the first electrostatic protection circuit 102, and the second end of the first transistor 102a and the second end of the second transistor 102b are connected to the third end of the first electrostatic protection circuit 102. The first transistor 102a is used for performing electrostatic protection on a first end of the microphone, and the second transistor is used for performing electrostatic protection on a second end of the microphone.
In some embodiments, with continued reference to fig. 3, the first filter circuit 103 is formed by a combination of a third capacitor 103a and a fourth capacitor 103 b. The first and second ends of the third capacitor 103a are connected to the first and third ends of the first filter circuit 103, respectively, and the first and second ends of the fourth capacitor 103b are connected to the second and fourth ends of the first filter circuit 103, respectively. The third capacitor 103a is used for filtering the audio signal input by the first differential input terminal 10a, and the fourth capacitor 103b is used for filtering the audio signal input by the second differential input terminal 10 b. The third capacitor 103a and the fourth capacitor 103b can improve the quality of the first audio signal by filtering out noise signals in the first audio signal.
In some embodiments, audio extraction circuit 30 includes two differential inputs and two differential outputs. Fig. 4 is a schematic circuit diagram of an audio extraction circuit according to an embodiment of the present application. Referring to fig. 4, the audio extraction circuit 30 includes a first differential input terminal 30a, a second differential input terminal 30b, a first differential output terminal 30c, and a second differential output terminal 30d. The first and second differential inputs 30a and 30b are connected to the first and second ends of the speaker, respectively. The first differential output terminal 30c and the second differential output terminal 30d are connected to a first input terminal and a second input terminal of the second analog-to-digital conversion circuit 40, respectively. Wherein the first differential input 30a and the second differential input 30b are capable of differentially transmitting the second audio signal output by the speaker. The audio signal input by the first differential input terminal 30a and the audio signal input by the second differential input terminal 30b are differential signals, and the amplitudes of the two signals are the same and the phases are opposite. Similarly, the first differential output terminal 30c and the second differential output terminal 30d are capable of differentially transmitting the sampled second audio signal. The audio signal output by the first differential output terminal 30c and the audio signal input by the second differential output terminal 30d are differential signals, and the amplitudes of the two signals are the same and the phases are opposite. The audio extraction circuit 30 can input the sampled second audio signal to the second analog-to-digital conversion circuit 40 through the first differential output terminal 30c and the second differential output terminal 30d, and the second analog-to-digital conversion circuit 40 can convert the sampled second audio signal into a digital audio signal. The second analog-to-digital conversion circuit 40 inputs the digital audio signal to the digital signal processor 50 through an output terminal, and the digital audio signal of the second audio signal is processed by the digital signal processor 50.
In some embodiments, audio extraction circuit 30 further includes a second electrostatic protection circuit, a resistive voltage divider circuit, and a second filter circuit. Fig. 5 is a schematic diagram of another audio extraction circuit according to an embodiment of the present application. Referring to fig. 5, the audio extraction circuit 30 further includes a third ground terminal A4, a second electrostatic protection circuit 301, a resistor voltage divider circuit 302, and a second filter circuit 303. The first end and the second end of the second electrostatic protection circuit 301 are respectively connected to the first differential input terminal 30a and the second differential input terminal 30b, and the third end of the second electrostatic protection circuit 301 is connected to the third ground terminal A4. The first and second ends of the resistor divider circuit 302 are connected to the first and second differential input terminals 30a and 30b, respectively, the third and fourth ends of the resistor divider circuit 302 are connected to the first and second ends of the second filter circuit 303, respectively, and the fifth end of the resistor divider circuit 302 is connected to the third ground terminal A4. The third terminal and the fourth terminal of the second filter circuit 303 are connected to the first differential output terminal 30c and the second differential output terminal 30d, respectively, and the fifth terminal of the second filter circuit 303 is connected to the third ground terminal A4. The second electrostatic protection circuit 301 is used for performing electrostatic protection on the speaker, so as to prevent the speaker from being damaged by electrostatic discharge. The resistor divider circuit 302 is used for dividing the voltage between the first differential input terminal 30a and the second differential input terminal 30b, protecting the circuit from excessive voltage, and ensuring that the circuit can work normally. The second filter circuit 303 is configured to filter the second audio signal, and by filtering noise in the second audio signal, the quality of the second audio signal can be improved, and the stability of the second audio signal can be improved.
In some embodiments, with continued reference to fig. 5, the second electrostatic protection circuit 301 is formed by combining a third transistor 301a and a fourth transistor 301 b. The first terminal of the third transistor 301a is connected to the first terminal of the second electrostatic protection circuit 301, the first terminal of the fourth transistor 301b is connected to the second terminal of the second electrostatic protection circuit, and the second terminal of the third transistor 301a and the second terminal of the fourth transistor 301b are connected to the third section of the second electrostatic protection circuit 301. The third transistor 301a is used for performing electrostatic protection on the first end of the speaker, and the fourth transistor 301b is used for performing electrostatic protection on the second end of the speaker.
In some embodiments, with continued reference to fig. 5, the resistor divider circuit 302 is formed by combining a fourth resistor 302a, a fifth resistor 302b, a sixth resistor 302c, and a seventh resistor 302 d. The first end of the fourth resistor 302a is connected to the first end of the resistor divider circuit 302, the second end of the fourth resistor 302a and the first end of the fifth resistor 302b are connected to the third end of the resistor divider circuit 302, the first end of the sixth resistor 302d is connected to the second end of the resistor divider circuit 302, the first end of the sixth resistor 302c and the second end of the seventh resistor 302d are connected to the fourth end of the resistor divider circuit 302, and the second end of the fifth resistor 302b and the second end of the sixth resistor 302c are connected to the fifth end of the resistor divider circuit 302. The fourth resistor 302a and the fifth resistor 302b are used for dividing the voltage between the first differential input terminal 30a and the third ground terminal A4, and the sixth resistor 302c and the seventh resistor 302d are used for dividing the voltage between the second differential input terminal 30b and the third ground terminal A4. The fourth resistor 302a, the fifth resistor 302b, the sixth resistor 302c, and the seventh resistor 302d can also limit the current in the circuit, and avoid damage to the electronic device caused by excessive current in the circuit.
In some embodiments, with continued reference to fig. 5, the second filter circuit 303 is formed by combining an eighth resistor 303a, a fifth capacitor 303b, a sixth capacitor 303c, a ninth resistor 303d, a seventh capacitor 303e, and an eighth capacitor 303 f. The first end of the eighth resistor 303a is connected to the first end of the sixth capacitor 303c and the first end of the second filter circuit 303, the second end of the eighth resistor 303a is connected to the first end of the fifth capacitor 303b and the third end of the second filter circuit 303, the first end of the ninth resistor 303d is connected to the first end of the eighth capacitor 303f and the second end of the second filter circuit 303, the second end of the ninth resistor 303d and the first end of the seventh capacitor 303e are connected to the fourth end of the second filter circuit 303, and the second end of the fifth capacitor 303b, the second end of the sixth capacitor 303c, the second end of the seventh capacitor 303e, and the second end of the eighth capacitor 303f are connected to the fifth end of the second filter circuit 303. The eighth resistor 303a, the fifth capacitor 303b, and the sixth capacitor 303c are configured to filter the audio signal input by the first differential input terminal 30a, and the ninth resistor 303d, the seventh capacitor 303e, and the eighth capacitor 303f are configured to filter the audio signal input by the second differential input terminal 30 b.
In some embodiments, the second analog-to-digital conversion circuit 40 is formed by combining a power supply circuit and an analog-to-digital converter. Fig. 6 is a schematic diagram of a second analog-to-digital conversion circuit according to an embodiment of the present application. Referring to fig. 6, the second analog-to-digital conversion circuit 40 includes a second power supply terminal A5, a fourth ground terminal A6, a second power supply circuit 401, and an analog-to-digital converter 402. The first end of the second power supply circuit 401 is connected to the second power supply end A5, the second end of the second power supply circuit 401 is connected to the power supply end of the analog-to-digital converter 402, and the third end of the second power supply circuit 401 is connected to the fourth ground end A6. The first input and the second input of the analog-to-digital converter 402 are connected to the first differential output 30c and the second differential output 30d, respectively, and the output of the analog-to-digital converter 402 is connected to the output 40a of the second analog-to-digital conversion circuit 40. The voltage provided by the second power supply terminal A5 may be any voltage in the operating voltage range of the analog-to-digital converter 402, which is not limited in the embodiment of the present application. The second power supply circuit 401 is used to supply power to the analog-to-digital converter 402. The analog-to-digital converter 402 is configured to perform analog-to-digital conversion on the sampled second audio signal, so as to obtain a digital audio signal of the second audio signal.
In some embodiments, the second analog-to-digital conversion circuit 40 is capable of converting the sampled second audio signal to a digital audio signal via the analog-to-digital converter 402 after receiving the sampled second audio signal. Since communication between the analog-to-digital converter 402 and the digital signal processor 50 is implemented using IIS (digital audio bus protocol), the analog-to-digital converter 402 can transmit the digital audio signal of the second audio signal to the digital signal processor 50 through IIS bus signals such as MRCK (master clock), LRCK (frame clock), SCLK (serial clock), CCLK (core clock), CDATA (data signal), and the like.
The circuit structure of the first analog-to-digital conversion circuit 20 is substantially the same as that of the second analog-to-digital conversion circuit 40, and the embodiments of the present application will not be repeated.
In some embodiments, the digital signal processor 50 is formed by a combination of signal processing circuitry and digital to analog conversion circuitry. Fig. 7 is a schematic diagram of a digital signal processor according to an embodiment of the present application. Referring to fig. 7, the digital signal processor 50 includes a signal processing circuit 501 and a digital-to-analog conversion circuit 502. An input end of the signal processing circuit 501 is connected to an output end of the first analog-to-digital conversion circuit 20, an input end of the signal processing circuit 501 is connected to an output end of the second analog-to-digital conversion circuit 40, an output end of the signal processing circuit 501 is connected to an input end of the digital-to-analog conversion circuit 502, and an output end of the digital-to-analog conversion circuit 502 is connected to a speaker. Wherein the signal processing circuit 501 is configured to perform echo cancellation on the digital audio signal of the first audio signal based on the digital audio signal of the second audio signal. The signal processing circuit 501 can obtain the voice information of the first audio signal and the voice information of the second audio signal by processing the digital audio signal of the first audio signal and the digital audio signal of the second audio signal. The signal processing circuit 501 is capable of canceling the same speech information in the first audio signal as the speech information in the second audio signal, that is, canceling the echo signal in the first audio signal by comparing the speech information in the first audio signal with the speech information in the second audio signal, to obtain a digital audio signal of the echo-canceled first audio signal. The digital-to-analog conversion circuit 502 is configured to perform digital-to-analog conversion on the digital audio signal after echo cancellation, and can obtain the first audio signal after echo cancellation by converting the digital audio signal after echo cancellation into an analog audio signal.
In some embodiments, the speaker includes an audio amplification circuit. Fig. 8 is a schematic diagram of an audio amplifying circuit according to an embodiment of the present application. Referring to fig. 8, the audio amplifying circuit 60 includes a third power supply terminal A7, a fifth ground terminal A8, a signal converting circuit 601, an audio amplifier 602, and a third power supply circuit 603. The first end and the second end of the signal conversion circuit 601 are respectively connected with the first output end and the second output end of the digital signal processor 30, and the third end of the signal conversion circuit 601 is connected with the input end of the audio amplifier 602. The first output terminal and the second output terminal of the audio amplifier 602 are connected to the first terminal and the second terminal of the speaker, respectively, and since the first terminal and the second terminal of the speaker are connected to the first differential input terminal 30a and the second differential input terminal 30b of the audio extraction circuit 30, respectively, the first output terminal and the second output terminal of the audio amplifier 602 are also connected to the first differential input terminal 30a and the second differential input terminal 30b of the audio extraction circuit 30, respectively. The first end of the third power supply circuit 603 is connected to the third power supply terminal A7, the second end of the third power supply circuit 603 is connected to the power supply terminal of the audio amplifier 602, and the third end of the third power supply circuit 603 is connected to the fifth ground terminal A8. The signal conversion circuit 601 is configured to convert a differential audio signal in the first input terminal and the second input terminal into a single-ended audio signal. The audio amplifier 602 is configured to power amplify the single-ended audio signal output from the signal conversion circuit 601, and output the power amplified audio signal to a speaker. The third power supply circuit 603 is for supplying power to the audio amplifier 602. The voltage provided by the third power supply terminal A7 may be any voltage in the operating voltage range of the audio amplifier 602, which is not limited in the embodiment of the present application.
Optionally, the audio amplifying circuit 40 can improve the quality of the audio signal through the smart amplifier technology, so that high-quality audio output can be realized through the speaker, and a louder, clearer and more immersive audio experience is provided for the user.
The embodiment of the application provides an echo cancellation circuit, which can sample a first audio signal acquired at the current moment of a microphone and a second audio signal output at the last moment of a loudspeaker through an audio sampling circuit and an audio extraction circuit, and then perform analog-to-digital conversion on the sampled audio signals through a first analog-to-digital conversion circuit and a second analog-to-digital conversion circuit, so that respective digital audio signals can be obtained. The digital signal processor processes the respective digital audio signals, and the echo cancellation can be performed on the first audio signal by comparing the digital audio signal of the first audio signal with the digital audio signal of the second audio signal, i.e. the echo signal in the first audio signal which is identical to the second audio signal is cancelled. The interference of the echo signals to the human voice is avoided, and the user experience is improved.
In an embodiment of the present application, there is also provided an audio device including the above-mentioned echo cancellation circuit, a microphone, and a speaker.
It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program for instructing relevant hardware, where the program may be stored in a computer readable storage medium, and the storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.
The foregoing description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, since it is intended that all modifications, equivalents, improvements, etc. that fall within the spirit and scope of the invention.
Claims (10)
1. An echo cancellation circuit, the echo cancellation circuit comprising: an audio sampling circuit (10), a first analog-to-digital conversion circuit (20), an audio extraction circuit (30), a second analog-to-digital conversion circuit (40), and a digital signal processor (50);
the input end of the audio sampling circuit (10) is connected with a microphone, the output end of the audio sampling circuit (10) is connected with the input end of the first analog-to-digital conversion circuit (20), the audio sampling circuit (10) is used for sampling a first audio signal acquired at the current moment of the microphone, and the first analog-to-digital conversion circuit (20) is used for carrying out analog-to-digital conversion on the sampled first audio signal to obtain a digital audio signal of the first audio signal;
The output end of the first analog-to-digital conversion circuit (20) is connected with the input end of the digital signal processor (50);
the input end of the audio extraction circuit (30) is connected with a loudspeaker, the output end of the audio extraction circuit (30) is connected with the input end of the second analog-to-digital conversion circuit (40), the audio extraction circuit (30) is used for sampling a second audio signal output by the loudspeaker at the last moment, and the second analog-to-digital conversion circuit (40) is used for carrying out analog-to-digital conversion on the sampled second audio signal to obtain a digital audio signal of the second audio signal;
the output end of the second analog-to-digital conversion circuit (40) is connected with the input end of the digital signal processor (50);
the output end of the digital signal processor (50) is connected with the loudspeaker, the digital signal processor (50) is used for carrying out echo cancellation on the first audio signal based on the digital audio signal of the first audio signal and the digital audio signal of the second audio signal, and the loudspeaker is used for playing the first audio signal after echo cancellation.
2. The echo cancellation circuit according to claim 1, wherein the audio sampling circuit (10) comprises a first differential input (10 a), a second differential input (10 b), a first differential output (10 c) and a second differential output (10 d);
The first differential input end (10 a) and the second differential input end (10 b) are respectively connected with a first end and a second end of the microphone;
the first differential output end (10 c) and the second differential output end (10 d) are respectively connected with a first input end and a second input end of the first analog-digital conversion circuit (20).
3. The echo cancellation circuit according to claim 2, wherein the audio sampling circuit (10) further comprises a first power supply terminal (A1), a first ground terminal (A2), a second ground terminal (A3), a first power supply circuit (101), a first electrostatic protection circuit (102), a first filter circuit (103), a first resistor (104) and a second resistor (105);
a first end of the first power supply circuit (101) is connected with the first power supply end (A1), a second end of the first power supply circuit (101) is connected with a first end of the first resistor (104), a third end of the first power supply circuit (101) is connected with the first grounding end (A2), and the first power supply circuit (101) is used for supplying power to the microphone;
the first end and the second end of the first electrostatic protection circuit (102) are respectively connected with the first differential input end (10 a) and the second differential input end (10 b), the third end of the first electrostatic protection circuit (102) is connected with the second grounding end (A3), and the first electrostatic protection circuit (102) is used for carrying out electrostatic protection on the microphone;
A first end and a second end of the first filter circuit (103) are respectively connected with the first differential input end (10 c) and the second differential input end (10 d), a third end and a fourth end of the first filter circuit (103) are respectively connected with the first differential output end (10 c) and the second differential output end (10 d), and the first filter circuit (103) is used for filtering the first audio signal;
-a second end of the first resistor (104) is connected to the first differential input (10 a), the first resistor (104) being adapted to provide a bias voltage to the microphone;
the first end of the second resistor (105) is connected with the second differential input end (10 b), the second end of the second resistor (105) is connected with the second grounding end (A3), and the second resistor (105) is used for providing bias voltage for the microphone.
4. An echo cancellation circuit according to claim 3, wherein the first supply circuit (101) comprises a third resistor (101 a), a first capacitor (101 b) and a second capacitor (101 c);
a first end of the third resistor (101 a) is connected with a first end of the first power supply circuit (101), and a second end of the third resistor (101 a) is connected with a second end of the first power supply circuit (101);
A first end of the first capacitor (101 b) is connected with a first end of the first power supply circuit (101), and a second end of the first capacitor (101 b) is connected with a third end of the first power supply circuit (101);
the first end of the second capacitor (101 c) is connected with the second end of the first power supply circuit (101), and the second end of the second capacitor (101 c) is connected with the third end of the first power supply circuit (101).
5. An echo cancellation circuit according to claim 3, characterized in that the first filter circuit (103) comprises a third capacitance (103 a) and a fourth capacitance (103 b);
a first end of the third capacitor (103 a) is connected with a first end of the first filter circuit (103), and a second end of the third capacitor (103 a) is connected with a third end of the first filter circuit (103);
the first end of the fourth capacitor (103 b) is connected with the second end of the first filter circuit (103), and the second end of the fourth capacitor (103 b) is connected with the fourth end of the first filter circuit (103).
6. The echo cancellation circuit according to claim 1, wherein the audio extraction circuit (30) comprises a first differential input (30 a), a second differential input (30 b), a first differential output (30 c) and a second differential output (30 d);
The first differential input terminal (30 a) and the second differential input terminal (30 b) are respectively connected with a first terminal and a second terminal of the loudspeaker;
the first differential output end (30 c) and the second differential output end (30 d) are respectively connected with a first input end and a second input end of the second analog-to-digital conversion circuit (40).
7. The echo cancellation circuit according to claim 6, wherein the audio extraction circuit (30) further comprises a third ground (A4), a second electrostatic protection circuit (301), a resistive voltage divider circuit (302) and a second filter circuit (303);
the first end and the second end of the second electrostatic protection circuit (301) are respectively connected with the first differential input end (30 a) and the second differential input end (30 b) of the audio extraction circuit (30), the third end of the second electrostatic protection circuit (301) is connected with the third grounding end (A4), and the second electrostatic protection circuit (301) is used for carrying out electrostatic protection on the loudspeaker;
the first end and the second end of the resistor divider circuit (302) are respectively connected with the first differential input end (30 a) and the second differential input end (30 b) of the audio extraction circuit (30), the third end and the fourth end of the resistor divider circuit (302) are respectively connected with the first end and the second end of the second filter circuit (303), the fifth end of the resistor divider circuit (302) is connected with the third grounding end (A4), the resistor divider circuit (302) is used for dividing the voltage between the first differential input end (30 a) and the second differential input end (30 b) of the audio extraction circuit (30), and the second filter circuit (303) is used for filtering the second audio signal;
The third end and the fourth end of the second filter circuit (303) are respectively connected with the first differential output end (30 c) and the second differential output end (30 d) of the audio extraction circuit (30), and the fifth end of the second filter circuit (303) is connected with the third grounding end (A4).
8. The echo cancellation circuit according to claim 1, wherein the second analog-to-digital conversion circuit (40) comprises a second power supply terminal (A5), a fourth ground terminal (A6), a second power supply circuit (401) and an analog-to-digital converter (402);
the first end of the second power supply circuit (401) is connected with the second power supply end (A5), the second end of the second power supply circuit (401) is connected with the power supply end of the analog-to-digital converter (402), the third end of the second power supply circuit (401) is connected with the fourth grounding end (A6), the second power supply circuit (401) is used for supplying power to the analog-to-digital converter (402), and the analog-to-digital converter (402) is used for performing analog-to-digital conversion on the sampled second audio signal to obtain a digital audio signal of the second audio signal;
the first input end and the second input end of the analog-to-digital converter (402) are respectively connected with the first differential output end (30 c) and the second differential output end (30 d) of the audio extraction circuit (30), and the output end of the analog-to-digital converter (402) is connected with the output end of the second analog-to-digital conversion circuit (40).
9. The echo cancellation circuit according to claim 1, wherein the digital signal processor (50) comprises a signal processing circuit (501) and a digital to analog conversion circuit (502);
the input end of the signal processing circuit (501) is connected with the output end of the first analog-to-digital conversion circuit (20), the input end of the signal processing circuit (301) is connected with the output end of the second analog-to-digital conversion circuit (40), the output end of the signal processing circuit (501) is connected with the input end of the digital-to-analog conversion circuit (502), the signal processing circuit (501) is used for carrying out echo cancellation on the digital audio signal of the first audio signal based on the digital audio signal of the second audio signal, and the digital-to-analog conversion circuit (502) is used for carrying out digital-to-analog conversion on the digital audio signal after echo cancellation to obtain the first audio signal after echo cancellation;
an output end of the digital-to-analog conversion circuit (502) is connected with the loudspeaker.
10. An audio device comprising the echo cancellation circuit of any one of claims 1 to 9, a microphone and a speaker.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310363401.2A CN116546388A (en) | 2023-04-06 | 2023-04-06 | Echo cancellation circuit and audio device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310363401.2A CN116546388A (en) | 2023-04-06 | 2023-04-06 | Echo cancellation circuit and audio device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116546388A true CN116546388A (en) | 2023-08-04 |
Family
ID=87446008
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310363401.2A Pending CN116546388A (en) | 2023-04-06 | 2023-04-06 | Echo cancellation circuit and audio device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116546388A (en) |
-
2023
- 2023-04-06 CN CN202310363401.2A patent/CN116546388A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP1493303B1 (en) | Microphone assembly with auxiliary analog input | |
| US8649528B2 (en) | Microphone unit with internal A/D converter | |
| US7978863B2 (en) | Apparatus and method to provide advanced microphone bias | |
| CN101123629A (en) | An environmental noise filtering method and device for mobile phone | |
| CN109218882B (en) | Earphone and ambient sound monitoring method thereof | |
| JP2011013403A (en) | Ambient noise removal device | |
| US9998079B2 (en) | Amplifiers | |
| CN104036771A (en) | Signal processing device, signal processing method, and storage medium | |
| CN210202036U (en) | Noise suppression device and earphone | |
| CN116546388A (en) | Echo cancellation circuit and audio device | |
| US9668045B1 (en) | Integrated phantom-powered JFET circuit module in portable electronic device for creating hi-fidelity sound characteristics | |
| WO2023072155A1 (en) | Rfid card reading circuit and electronic device | |
| CN220156644U (en) | Echo cancellation circuit and audio device | |
| CN111083250A (en) | Mobile terminal and noise reduction method thereof | |
| CN111526443B (en) | Ear return earphone circuit, ear return earphone and ear return system | |
| CN112637438B (en) | Entrance guard double-end intercom method and system based on single-line transmission | |
| JP4976012B2 (en) | Audio signal amplitude limiter | |
| CN208316971U (en) | earphone and communication system | |
| CN108200498A (en) | A kind of earphone with pickup function | |
| CN112969126A (en) | Acoustic sensor system, signal processing system, method and electronic device | |
| CN219780367U (en) | ADC circuit and electronic device | |
| CN114531628A (en) | Hearing device, signal processing method and device | |
| CN116156385B (en) | Filtering method, filtering device, chip and earphone | |
| CN218570446U (en) | Wireless meeting microphone unit based on movable base | |
| CN218240722U (en) | Audio transmission circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |