CN107889007B - Active noise reduction method and system for eliminating influence of noise reduction channel on playing sound - Google Patents
Active noise reduction method and system for eliminating influence of noise reduction channel on playing sound Download PDFInfo
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- CN107889007B CN107889007B CN201711026343.5A CN201711026343A CN107889007B CN 107889007 B CN107889007 B CN 107889007B CN 201711026343 A CN201711026343 A CN 201711026343A CN 107889007 B CN107889007 B CN 107889007B
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- 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
- H04R3/02—Circuits for transducers, loudspeakers or microphones for preventing acoustic reaction, i.e. acoustic oscillatory feedback
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/10—Earpieces; Attachments therefor ; Earphones; Monophonic headphones
- H04R1/1083—Reduction of ambient noise
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Abstract
The invention provides an active noise reduction method for eliminating the influence of a noise reduction channel on playing sound, which comprises the steps of dividing a digital signal played by a playing source into a first path of digital signal and a second path of digital signal, converting the first path of digital signal into an analog electric signal through a DA converter, transmitting the analog electric signal to a player for sound playing, and transmitting the second path of digital signal to a first digital filter for filtering to obtain a digital elimination signal; a microphone collects a noise signal and a sound signal played by a player, and converts the collected noise signal and the sound signal into a digital mixed signal through an AD converter; and the digital mixed signal and the digital elimination signal are coupled by an adder and processed to output a third path of digital signal, and the third path of digital signal enters a noise reduction passage to eliminate environmental noise. The invention can eliminate noise and reduce the influence on the playing sound, thereby ensuring the quality of the playing sound in the sound cavity.
Description
Technical Field
The invention relates to the technical field of noise processing, in particular to an active noise reduction method and a noise reduction system for eliminating the influence of a noise reduction channel on playing sound.
Background
With the continuous development of intellectualization, the living standard of people is continuously improved, and the requirement of people on the earphone is gradually increased. Generally, there are two methods for headphone noise reduction, namely active noise reduction and passive noise reduction.
The active noise reduction is to cancel the noise sound wave by the noise reduction system sending the sound wave with the opposite phase to the environmental noise to eliminate the environmental noise, thereby realizing the noise reduction effect. Passive noise reduction is achieved by surrounding the ear to form a closed space, or by using sound insulation materials such as silica gel earplugs to block external noise. Compared with passive noise reduction, the active noise reduction earphone can effectively reduce the noise of low-frequency noise through the chip processing of the noise reduction circuit, so that the noise reduction effect is more ideal.
Active noise reduction earphones in the prior art have gradually come to the lives of people, so that people can obtain a relatively quiet environment in a noisy environment. However, the active noise reduction method in the prior art has a certain influence on the played sound, which leads to the overall reduction of the sound played by the earphone when the noise is eliminated, and the reduced sound is difficult to recover to the original quality.
Therefore, in order to solve the above problems, an active noise reduction method and a noise reduction system for eliminating the influence of a noise reduction path on a playing sound, which can eliminate the attenuation of the playing sound in the active noise reduction process, are needed.
Disclosure of Invention
One aspect of the present invention provides an active noise reduction method for eliminating the influence of a noise reduction path on a played sound, the method comprising:
dividing a digital signal played by a playing source into a first path of digital signal and a second path of digital signal, wherein the first path of digital signal is converted into an analog electric signal by a DA converter and transmitted to a player for sound playing, and the second path of digital signal is transmitted to a first digital filter for filtering to obtain a digital cancellation signal;
a microphone collects a noise signal and a sound signal played by a player, and converts the collected noise signal and the sound signal into a digital mixed signal through an AD converter;
and the digital mixed signal and the digital elimination signal are coupled by an adder and processed to output a third path of digital signal, and the third path of digital signal enters a noise reduction passage to eliminate environmental noise.
Preferably, the third digital signal is fed back to the first digital filter, and the digital cancellation signal is adjusted.
Preferably, the noise reduction path is a feedback noise reduction path, the noise reduction path being arranged with a second digital filter.
Preferably, the second digital filter filters the third path of digital signal, couples and superposes the filtered third path of digital signal with the first path of digital signal, and converts the filtered third path of digital signal into an analog electric signal through the DA converter;
and the analog electric signal is transmitted to a player for sound playing.
Preferably, the first digital filter is an adaptive filter or a fixed filter.
Preferably, the second digital filter is an adaptive filter or a fixed filter.
Preferably, the adjustment of the digital cancellation signal is performed as follows:
updating the weight vector: w (n +1) = w (n) +2 μ e (n) x (n), where w (n) is a weight vector, e (n) is a third path of digital signals, x (n) is a second path of digital signals, and μ is a step parameter;
updating the adjusted digital cancellation signal: y (n) ═ wT(n) x (n), wherein y (n) is the adjusted digital cancellation signal, wT(n) is the transposed vector of the weight vector, and x (n) is the second path of digital signal.
Preferably, the step size parameter μ satisfies: mu is more than 0 and less than 2/MPinWhere M is the filter length, Pin=E[x2(n)]The input power of the second path of digital signal.
Another aspect of the present invention is to provide an active noise reduction system for eliminating the influence of noise reduction paths on playing sound, the system comprising:
the digital signal played by the playing source is divided into a first path of digital signal and a second path of digital signal;
and the first filter directly filters the second path of digital signals played by the playing source to obtain digital elimination signals.
And the microphone collects noise signals from the environment and sound signals played by the player.
An AD converter converting the noise signal and the sound signal collected by the microphone into a digital mixed signal;
and the noise reduction path is used for receiving a third path of digital signals output by the adder after the digital elimination signals and the digital mixed signals are coupled and carrying out noise elimination.
Preferably, the third digital signal is fed back to the first digital filter, and the digital cancellation signal is adjusted.
According to the active noise reduction method and the active noise reduction system for eliminating the influence of the noise reduction channel on the playing sound, the playing sound is changed into two paths, one path is used for playing the sound, the other path is used for offsetting the sound which is acquired by the player through the microphone after being filtered by the first filter, so that the third path of analog electric signal for eliminating the noise is a single noise signal, and the phenomenon that the playing sound of the player is acquired in the noise elimination process to weaken the whole playing sound is eliminated.
The invention carries out digital noise elimination adjustment through the feedback of the third path of digital signals, can effectively purify the third path of digital signals, and greatly reduces the influence of the noise reduction process on the played sound.
The active noise reduction method and the noise reduction system for eliminating the influence of the noise reduction channel on the played sound effectively prevent the influence of the played sound collected by the microphone on the overall played sound in the active noise reduction process, so that the playing quality of the earphone is improved by one step.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
Drawings
Further objects, features and advantages of the present invention will become apparent from the following description of embodiments of the invention, with reference to the accompanying drawings, in which:
FIG. 1 schematically illustrates a headphone acoustic cavity using the active noise reduction system of the present invention;
FIG. 2 illustrates a signal transfer schematic of the active noise reduction system of the present invention;
fig. 3 shows a schematic diagram of the adjustment process of the digital cancellation signal of the present invention.
Detailed Description
The objects and functions of the present invention and methods for accomplishing the same will be apparent by reference to the exemplary embodiments. However, the present invention is not limited to the exemplary embodiments disclosed below; it can be implemented in different forms. The nature of the description is merely to assist those skilled in the relevant art in a comprehensive understanding of the specific details of the invention.
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, and related technical terms should be well known to those skilled in the art. In the drawings, the same reference numerals denote the same or similar parts, or the same or similar steps, unless otherwise specified. The following describes the content of the present invention with reference to a specific embodiment, where the content of the present invention is based on that in the active noise reduction process, the microphone collects noise and at the same time collects sound played by the player (for example, in music playing, the microphone collects noise and in the active noise reduction process collects music played by the player), and then in the active noise reduction process, the played sound is attenuated, which affects the quality of the played sound. The following describes the noise cancellation of the present invention by taking the process of playing music by a headset as an example, as shown in fig. 1, a schematic diagram of a sound cavity of a headset using the active noise reduction system of the present invention is shown, in this embodiment, a wired headset is taken as an example to connect a played sound signal to a signal processing chip 102 in the headset through a wire 105, and in some embodiments, the played sound signal may be a wireless headset, including but not limited to connecting the played sound signal to the signal processing chip 102 of the headset 100 by means of bluetooth. The active noise reduction system for eliminating the influence of the noise reduction channel on the playing sound in this embodiment includes:
the digital signal played by the playing source is divided into a first path of digital signal and a second path of digital signal. The playing source in the invention is a digital playing source, and the sound is output in a digital signal mode.
The first filter directly filters the second path of digital signals played by the playing source to obtain digital cancellation signals.
The microphone 103 collects noise signals from the environment and sound signals played by the player 104.
And an AD converter that converts the noise signal and the sound signal collected by the microphone 103 into a digital mixed signal.
And the noise reduction passage receives a third path of digital signals output by the adder after the digital elimination signals and the digital mixed signals are coupled and carries out noise elimination.
In this embodiment, the sound signal is connected to the earphone through the wire 105, and in the signal processing chip 102, the playing source converts the sound signal into a first path of digital signal and a second path of digital signal, and the first path of digital signal is converted by the DA converter and then enters the player 104 to play the sound, and then enters the ear 106 of the user. In the sound cavity 101 of the earphone 100, there is an influence of the environmental noise on the played sound, and according to the present embodiment of the present invention, the second path of digital signal and the microphone 103 collect the mixed sound (the environmental noise and the sound played by the player 104) and access the mixed sound to the signal processing chip 102 for processing. The processed clean noise is transmitted to the player 104 to play and eliminate the environmental noise in the sound cavity 101.
As shown in fig. 2, a signal transmission schematic diagram of the active noise reduction system of the present invention is provided, and the active noise reduction method for eliminating the influence of the noise reduction path on the playing sound provided by the present embodiment includes:
the digital signal played by the playing source 206 is divided into a first path of digital signal and a second path of digital signal, wherein the first path of digital signal is converted into an analog electrical signal by the DA converter 201 and transmitted to the player 104 for playing sound. The second path of digital signal is transmitted to the first digital filter 202 for filtering to obtain a digital cancellation signal. Preferably, the first filter 202 of the present embodiment is an adaptive filter, and in other embodiments, the first filter 202 may be a fixed filter.
The microphone 103 collects noise signals as well as sound signals played by the player 105, i.e. ambient noise and sound played by the player 104. The collected noise signal and sound signal are converted into a digital mixed signal by the AD converter 205.
The digital mixed signal and the digital eliminating signal are coupled by the adder 203 to output a third digital signal, and the third digital signal enters the noise reduction path to eliminate the environmental noise. Since the microphone 103 inevitably collects the sound signal played by the player 104, in order to prevent the existence of the sound wave weakened to the playing signal of the player 104 in the reverse sound wave for noise elimination output by the noise reduction path, the sound signal played by the player 104 in the digital mixed signal is eliminated in advance through the first digital filter 202 and the adder 203, so as to ensure that the noise signal in the noise reduction path is cleaner.
Further, in the present invention, a feedback mechanism is provided for the cancellation process of the sound signal played by the player 104, and the third digital signal is fed back to the first digital filter 202 to adjust the digital cancellation signal. As shown in fig. 3, the adjustment process of the digital cancellation signal according to the present invention is schematically illustrated, and the third digital signal is fed back to the first digital filter to adjust the digital cancellation signal.
Specifically, the adjustment of the digital cancellation signal is performed as follows:
updating the weight vector: w (n +1) = w (n) +2 μ e (n) x (n), where w (n) is a weight vector, e (n) is a third path of digital signals, x (n) is a second path of digital signals, μ is a step size parameter, and μ satisfies: mu is more than 0 and less than 2/MPinWhere M is the filter length, Pin=E[x2(n)]The input power of the second path of digital signal.
Updating the adjusted digital cancellation signal: y (n) ═ wT(n) x (n), wherein y (n) is the adjusted digital cancellation signal, wT(n) is the transposed vector of the weight vector, and x (n) is the second path of digital signal.
In this embodiment, the noise reduction path is a feedback noise reduction path, and the second digital filter 204 is disposed on the noise reduction path. And the second digital filter filters the third path of digital signals, couples and superposes the third path of digital signals with the first path of digital signals, converts the third path of digital signals into analog electric signals through the DA converter, and transmits the analog electric signals to the player for sound playing. And when the player plays the sound, the noise reduction is realized on the environmental noise. Preferably, the second filter 204 of the present embodiment is an adaptive filter, and in other embodiments, the second filter 204 may be a fixed filter.
By eliminating the sound signal played by the player 104 in the digital mixed signal by the method of the present invention, the third path of digital signal entering the noise reduction path is ensured to be a pure noise signal. The second digital filter 204 filters the third path of digital signal, couples and superposes the third path of digital signal with the first path of digital signal, and converts the third path of digital signal into an analog electric signal through the DA converter 201. The analog electrical signal is transmitted to the player 104 for sound playing to eliminate the noise in the sound cavity, so as to realize active noise reduction.
According to the active noise reduction method and the active noise reduction system for eliminating the influence of the noise reduction channel on the playing sound, the playing sound is changed into two paths, one path is used for playing the sound, the other path is used for offsetting the sound which is acquired by the player through the microphone after being filtered by the first filter, so that the third path of analog electric signal for eliminating the noise is a single noise signal, and the phenomenon that the playing sound of the player is acquired in the noise elimination process to weaken the whole playing sound is eliminated.
The invention carries out digital noise elimination adjustment through the feedback of the third path of digital signals, can effectively purify the third path of digital signals, and greatly reduces the influence of the noise reduction process on the played sound.
The active noise reduction method and the noise reduction system for eliminating the influence of the noise reduction channel on the played sound effectively prevent the influence of the played sound collected by the microphone on the overall played sound in the active noise reduction process, so that the playing quality of the earphone is improved by one step.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
Claims (7)
1. An active noise reduction method for eliminating the influence of a noise reduction channel on played sound, the method comprising:
dividing a digital signal played by a playing source into a first path of digital signal and a second path of digital signal, wherein the first path of digital signal is converted into an analog electric signal by a DA converter and transmitted to a player for sound playing, and the second path of digital signal is transmitted to a first digital filter for filtering to obtain a digital cancellation signal;
a microphone collects a noise signal and a sound signal played by a player, and converts the collected noise signal and the sound signal into a digital mixed signal through an AD converter;
the digital mixed signal and the digital elimination signal are coupled by an adder and processed to output a third path of digital signal, and the third path of digital signal enters a noise reduction passage to eliminate environmental noise;
feeding back the third digital signal to the first digital filter, and adjusting the digital cancellation signal, wherein the adjustment of the digital cancellation signal is performed according to the following method:
updating the weight vector: w (n +1) = w (n) +2 μ e (n) x (n), where w (n) is a weight vector, e (n) is a third path of digital signals, x (n) is a second path of digital signals, and μ is a step parameter;
outputting the adjusted digital cancellation signal: y (n) ═ wT(n) x (n), wherein y (n) is the adjusted digital cancellation signal, wT(n) is the transposed vector of the weight vector, and x (n) is the second path of digital signal.
2. The method of claim 1, wherein the noise reduction path is a feedback noise reduction path, the noise reduction path arranging a second digital filter.
3. The method of claim 2, wherein the second digital filter filters the third digital signal, couples and superposes the third digital signal with the first digital signal, and converts the third digital signal into an analog electrical signal through a DA converter;
and the analog electric signal is transmitted to a player for sound playing.
4. The method of claim 1, wherein the first digital filter is an adaptive filter or a fixed filter.
5. A method according to claim 2 or 3, wherein the second digital filter is an adaptive filter or a fixed filter.
6. The method according to claim 1, characterized in that the step size parameter μ satisfies: mu is more than 0 and less than 2/MPinWhere M is the filter length, Pin=E[x2(n)]The input power of the second path of digital signal.
7. An active noise reduction system for eliminating the effect of noise reduction paths on the played sound, the system comprising:
the digital signal played by the playing source is divided into a first path of digital signal and a second path of digital signal;
the first path of digital signal is converted into an analog electric signal by a DA converter and transmitted to a player for sound playing, the first digital filter directly filters a second path of digital signal played by a playing source to obtain a digital elimination signal,
the microphone is used for collecting noise signals from the environment and sound signals played by the player;
an AD converter converting the noise signal and the sound signal collected by the microphone into a digital mixed signal;
the noise reduction passage receives a third path of digital signals output by the adder after the digital elimination signals and the digital mixed signals are coupled, and carries out noise elimination;
feeding back the third digital signal to the first digital filter, and adjusting the digital cancellation signal, wherein the adjustment of the digital cancellation signal is performed according to the following method:
updating the weight vector: w (n +1) = w (n) +2 μ e (n) x (n), where w (n) is a weight vector, e (n) is a third path of digital signals, x (n) is a second path of digital signals, and μ is a step parameter;
outputting the adjusted digital cancellation signal: y (n) ═ wT(n) x (n), wherein y (n) is the adjusted digital cancellation signal, wT(n) is the transposed vector of the weight vector, and x (n) is the second path of digital signal.
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CN111627414B (en) * | 2019-02-28 | 2024-01-30 | 上海汽车集团股份有限公司 | Active denoising method and device and electronic equipment |
JP6822693B2 (en) | 2019-03-27 | 2021-01-27 | 日本電気株式会社 | Audio output device, audio output method and audio output program |
CN110418233A (en) * | 2019-07-26 | 2019-11-05 | 歌尔股份有限公司 | A kind of earphone noise-reduction method, device, earphone and readable storage medium storing program for executing |
WO2022140928A1 (en) * | 2020-12-28 | 2022-07-07 | 深圳市韶音科技有限公司 | Audio signal processing method and system for suppressing echo |
CN113163300A (en) * | 2021-03-02 | 2021-07-23 | 广州朗国电子科技有限公司 | Audio noise reduction circuit and electronic equipment |
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