阅读说明：本技术 降噪装置、降噪方法以及多媒体设备 (Noise reduction device, noise reduction method and multimedia equipment ) 是由 顾惠 于 2021-08-20 设计创作，主要内容包括：本发明公开一种降噪装置、降噪方法以及多媒体设备,降噪装置包括麦克风单元,用于对环境噪声进行实时监听并生成反噪声信号-N1；滤波单元,用于将反噪声信号-N1的频率特性补偿为-N2；加载载波单元,将补偿后的信号-N2加载到一高频载波C上,以形成与噪声信号N1相位相反的包络信号-N3；放大器单元,将包络信号-N3的幅值放大到与环境噪声相等的-N4；扬声器单元,播放放大器单元输出的放大信号-N4以降低环境噪声。由于采用了以上技术手段,本发明具有以下优点：在嘈杂的环境中,可以利用手中的设备,比如笔记本电脑、手机、一体机或是平板,创造一个相对安静的环境；通过主动式降噪控制,破坏性地干扰非期望声波,大幅降低非期望的声音；通过扬声器输出的反噪声信号,可以产生在某个位置的某个三维区域的低噪声区。(The invention discloses a noise reduction device, a noise reduction method and multimedia equipment, wherein the noise reduction device comprises a microphone unit, a noise reduction unit and a noise cancellation unit, wherein the microphone unit is used for monitoring environmental noise in real time and generating an anti-noise signal-N1; a filtering unit for compensating a frequency characteristic of the anti-noise signal-N1 to-N2; a loading carrier unit, which loads the compensated signal-N2 on a high-frequency carrier C to form an envelope signal-N3 with the phase opposite to that of the noise signal N1; an amplifier unit amplifying the amplitude of the envelope signal-N3 to-N4 equal to the ambient noise; and a speaker unit playing the amplified signal-N4 output by the amplifier unit to reduce ambient noise. Due to the adoption of the technical means, the invention has the following advantages: in a noisy environment, a relatively quiet environment can be created by using equipment in hands, such as a notebook computer, a mobile phone, an all-in-one machine or a tablet computer; through active noise reduction control, undesired sound waves are destructively disturbed, and the undesired sound is greatly reduced; the low noise region of a certain three-dimensional region at a certain position can be generated by the anti-noise signal output from the speaker.)

1. A noise reducing device, comprising:

the microphone unit is used for monitoring environmental noise in real time and generating an anti-noise signal-N1;

a filtering unit for compensating a frequency characteristic of the anti-noise signal-N1 to-N2;

a loading carrier unit, loading the compensated signal-N2 on a high-frequency carrier C to form an envelope signal-N3 with the phase opposite to that of the noise signal N1;

an amplifier unit amplifying the amplitude of the envelope signal-N3 to-N4 equal to the ambient noise;

and a speaker unit playing the amplified signal-N4 output by the amplifier unit to reduce ambient noise.

2. The noise reduction device according to claim 1, characterized in that: the microphone unit comprises a reverse microphone component.

3. The noise reduction device according to claim 1, characterized in that: comprises a carrier generation unit for generating a high frequency carrier C.

4. The noise reduction device according to claim 3, characterized in that: the frequency of the high-frequency carrier C is greater than the upper limit of the human ear identification frequency.

5. The noise reduction device according to claim 1, characterized in that: comprising a comparator unit for comparing the amplitude of the envelope signal-N3 with the ambient noise, said amplifier unit adjusting the amplitude of the envelope signal-N3 in dependence on the comparison result.

6. The noise reduction device according to claim 1, characterized in that: the filtering unit filters high frequency parts of the anti-noise signal-N1 which are larger than the human ear discrimination.

7. The noise reduction device according to claim 6, wherein: the filtering unit includes:

a power supply component: comprises a resistor R1 connected with the microphone unit and a voltage source VDC;

an impedance matching section: a capacitor C1 is included for removing the DC component in the anti-noise signal input by the microphone unit;

a low-pass filtering section: including second order low pass filtering consisting of R2, R3, C2 and C3 for removing a high frequency region in the output signal from the impedance matching block and preserving a low frequency region of the anti-noise signal.

8. A method of noise reduction, characterized by: the method comprises the following steps:

s1, real-time monitoring is carried out on the environmental noise and an anti-noise signal-N1 is generated;

s2, filtering the high frequency part which is larger than the human ear in the anti-noise signal-N1, and matching and compensating the impedance and the output end to-N2;

s3, loading the compensated signal-N2 on a high-frequency carrier C with the frequency larger than the upper limit of the human ear identification frequency to form an envelope signal-N3 with the phase opposite to that of the noise signal N1;

s4, amplifying the amplitude of the envelope signal-N3 to-N4 equal to the environmental noise;

s5, playing the amplified signal-N4 to reduce the environmental noise.

9. A multimedia device, characterized by: having a noise reducing arrangement as claimed in any one of claims 1 to 7.

10. The multimedia device of claim 9, wherein: the mobile phone comprises a mobile phone, a tablet personal computer, a notebook computer, a desktop computer and an all-in-one computer.

Technical Field

The present invention relates to a noise reduction device and a noise reduction method.

Background

With the development of science and technology and the wider application of intelligent multimedia devices, people also face a serious pollution problem while enjoying various conveniences brought to the human by modern science and technology. Among these pollution, noise pollution is one of the pollution sources that directly endanger the physical and mental health of people. In many occasions, such as industrial production process, daily life working environment, laboratory environment, etc., sound noise exists, and some are even serious. These noises are detrimental to workers who are in close contact for a long time, cause serious harm to their physiological and psychological health, and are prone to hearing loss, fatigue and attention loss. Therefore, under the condition that the noise is more serious and people are more pursuing physical and psychological health and quality of life, the reduction of the noise is strongly demanded.

Any acoustic system includes 3 elements of acoustic source, propagation path and recipient, from which control of noise should be performed. The existing noise reduction methods mainly comprise a passive noise reduction method and an active noise reduction method.

Passive noise reduction can be divided into three processing methods of damping noise, sound absorbing noise and sound insulation noise. It separates the external noise from the ear by physical characteristics, mainly blocks the noise by sound insulation material, is very effective to high frequency sound, and generally can reduce the noise by about 15-20 dB. The method has simple principle and low noise reduction cost, but has inferior effect. High-density sound-insulating materials are generally used, or earphones are worn, which make people feel uncomfortable. The passive noise reduction has good isolation effect on high-frequency signals, such as acoustic panels beside roads. However, the effects of low-frequency noise in a small space, such as air conditioner operation noise, projector operation noise, engine noise, rain noise, wind noise, wave noise, and cicada sound, are greatly reduced.

For active noise reduction, the principle of 2 sound wave destructive interference or sound wave radiation suppression is used. The method comprises the following specific steps: the purpose of noise reduction is achieved by artificially manufacturing 1 control sound source (secondary sound source) to make the sound emitted by the control sound source equal in magnitude and opposite in phase to the original noise source (primary sound source), and offsetting the action results of the two.

Disclosure of Invention

It is an object of the present invention to overcome the disadvantages of the prior art and to provide a method and apparatus for active noise reduction, which reduces undesired sounds in a specific area by signal processing, audio processing and noise control.

In order to achieve the above object, the present invention provides a noise reduction device comprising: the microphone unit is used for monitoring environmental noise in real time and generating an anti-noise signal-N1; a filtering unit for compensating a frequency characteristic of the anti-noise signal-N1 to-N2; a loading carrier unit, which loads the compensated signal-N2 on a high-frequency carrier C to form an envelope signal-N3 with the phase opposite to that of the noise signal N1; an amplifier unit amplifying the amplitude of the envelope signal-N3 to-N4 equal to the ambient noise; and a speaker unit playing the amplified signal-N4 output by the amplifier unit to reduce ambient noise.

Preferably, the microphone unit comprises a reverse microphone component.

Preferably, a carrier generation unit is included for generating the high frequency carrier C.

Preferably, the frequency of the high-frequency carrier C is greater than the upper limit of the human ear discrimination frequency.

Preferably, a comparator unit is included for comparing the amplitude of the envelope signal-N3 with the ambient noise, and the amplifier unit adjusts the amplitude of the envelope signal-N3 according to the comparison result.

Preferably, the filtering unit filters a high frequency part of the anti-noise signal-N (1) greater than human ear discrimination.

Preferably, the filtering unit includes: a power supply component: comprises a resistor R1 connected with the microphone unit and a voltage source VDC; an impedance matching section: a capacitor C1 is included for removing the DC component in the anti-noise signal input by the microphone unit; a low-pass filtering section: including second order low pass filtering consisting of R2, R3, C2 and C3 for removing a high frequency region in the output signal from the impedance matching block and preserving a low frequency region of the anti-noise signal.

According to another aspect of the present invention, there is provided a noise reduction method, comprising the steps of:

s1, real-time monitoring is carried out on the environmental noise and an anti-noise signal-N1 is generated;

s2, filtering the high frequency part which is larger than the human ear in the anti-noise signal-N1, and matching and compensating the impedance and the output end to-N2;

s3, loading the compensated signal-N2 on a high-frequency carrier C with the frequency larger than the upper limit of the human ear identification frequency to form an envelope signal-N3 with the phase opposite to that of the noise signal N1;

s4, amplifying the amplitude of the envelope signal-N3 to-N4 equal to the environmental noise;

s5, playing the amplified signal-N4 to reduce the environmental noise.

According to another aspect of the present invention, there is provided a multimedia device having the noise reduction apparatus as described above.

Preferably, the mobile phone comprises a mobile phone, a tablet computer, a notebook computer, a desktop computer and an all-in-one computer.

Due to the adoption of the technical means, the invention has the following advantages:

1. in a noisy environment, a relatively quiet environment can be created by using equipment in hands, such as a notebook computer, a mobile phone, an all-in-one machine or a tablet computer;

2. through active noise reduction control, undesired sound waves are destructively disturbed, and the undesired sound is greatly reduced;

3. the low noise region of a certain three-dimensional region at a certain position can be generated by the anti-noise signal output from the speaker.

Drawings

Fig. 1 is a block diagram of a noise reducing device according to the present invention;

FIG. 2 is a schematic diagram of the operation of a noise reducer according to the present invention;

fig. 3 is a circuit diagram of a filtering unit of the noise reducing apparatus according to the present invention;

FIG. 4 is a flow chart of a noise reduction method according to the present invention;

FIG. 5 is a waveform that exhibits phase characteristics of an output signal relative to an input signal relative to the type of microphone;

fig. 6 is a waveform diagram of signals before and after loading a carrier unit.

Detailed Description

The following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings, will make the advantages and features of the invention easier to understand by those skilled in the art, and thus will clearly and clearly define the scope of the invention.

The embodiment discloses a noise reduction device which can be applied to multimedia equipment comprising a mobile phone, a tablet computer, a notebook computer, a desktop computer and an all-in-one computer. The existing noise reduction technology is mainly based on an active noise reduction and elimination technology to realize noise elimination of a far-end voice signal during voice communication, and environmental noise cannot be really reduced because the voice noise during the communication is only reduced.

Fig. 1 is a block diagram of a noise reduction apparatus according to the present invention, and fig. 2 is a schematic diagram of an operation of the noise reduction apparatus according to the present invention. The noise reduction device in this embodiment includes: the microphone unit is used for monitoring environmental noise in real time and generating an anti-noise signal-N1; a filtering unit for compensating a frequency characteristic of the anti-noise signal-N1 to-N2; a loading carrier unit, which loads the compensated signal-N2 on a high-frequency carrier C to form an envelope signal-N3 with the phase opposite to that of the noise signal N1; an amplifier unit amplifying the amplitude of the envelope signal-N3 to-N4 equal to the ambient noise; and a speaker unit playing the amplified signal-N4 output by the amplifier unit to reduce ambient noise. Communication channel 1 is a wireless communication channel and communication channel 2 may be a flex or PCB conductor.

The upper stage of the amplifier unit may be provided with a comparator unit for comparing the amplitude of the envelope signal-N3 with the ambient noise, the amplifier unit adjusts the amplitude of the envelope signal-N3 according to the comparison result, and the filter unit filters the high frequency part of the anti-noise signal-N (1) greater than the discrimination of the human ear, because the high frequency part of the ambient noise greater than the discrimination of the human ear does not affect the human hearing, so that it is not necessary to perform noise reduction processing on the noise of the part, and at the same time, the difficulty of the noise reduction processing is reduced.

The high-frequency carrier C may be generated by one carrier generation unit, and the frequency of the generated high-frequency carrier C is greater than the upper limit of the human ear discrimination frequency because new noise cannot be generated during noise reduction.

Fig. 3 is a circuit diagram of a filtering unit of the noise reducing apparatus according to the present invention; the filter unit includes a power supply unit including a resistor R1 connected to the microphone unit, a voltage source VDC, an impedance matching unit including a capacitor C1 for removing a direct current component of an anti-noise signal inputted from the microphone unit, and a low pass filtering unit including a second order low pass filter composed of R2, R3, C2 and C3 for removing a high frequency region of a signal outputted from the impedance matching unit and retaining a low frequency region of the anti-noise signal.

Fig. 4 is a flow chart of a noise reduction method according to the invention, comprising the steps of:

s1, the anti-phase microphone monitors the environmental noise in real time and generates an anti-noise signal-N1;

s2, filtering the high frequency part which is larger than the human ear in the anti-noise signal-N1, and matching and compensating the impedance and the output end to-N2;

s3, loading the compensated signal-N2 on a high-frequency carrier C with the frequency larger than the upper limit of the human ear identification frequency to form an envelope signal-N3 with the phase opposite to that of the noise signal N1;

s4, amplifying the amplitude of the envelope signal-N3 to-N4 equal to the environmental noise;

s5, playing the amplified signal-N4 to reduce the environmental noise.

The noise reduction method has the following advantages:

1. in a noisy environment, a relatively quiet environment can be created by using equipment in hands, such as a notebook computer, a mobile phone, an all-in-one machine or a tablet computer;

2. through active noise reduction control, undesired sound waves are destructively disturbed, and the undesired sound is greatly reduced;

3. the low noise region of a certain three-dimensional region at a certain position can be generated by the anti-noise signal output from the speaker.

FIG. 5 is a waveform that exhibits phase characteristics of an output signal relative to an input signal relative to the type of microphone; the in-phase microphone has an output characteristic in phase with the input signal, and the anti-phase microphone has an output characteristic in anti-phase with the input signal. This example uses a microphone with an output characteristic that is out of phase (i.e., inverted) with the input signal. In this case, the output signal may be completely out of phase (i.e., 180 degrees out of phase) with the input signal. The microphone unit receives external noise and outputs a microphone signal (MIC +, MIC-) having an inverted output characteristic with respect to the received external noise. In other words, the microphone receives an input signal (e.g., external noise) and outputs an output signal (e.g., anti-noise) that is completely out of phase with the input signal, and the speaker unit outputs an anti-phase Audio signal (Audio +, Audio-).

Fig. 6 is a waveform diagram of signals before and after loading a carrier unit. After the microphone picks up the primary sound source signal, an anti-noise signal-N1-N1 is obtained, a signal-N2 is generated through the filtering unit, the anti-noise signal-N2 is loaded on a high-frequency band, and an envelope signal-N3 different in phase from the primary sound source is formed.

The above embodiments are merely illustrative of the technical concept and features of the present invention, and the present invention is not limited thereto, and any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of the present invention.