CN115802250A

CN115802250A - Miniature indoor noise reduction electronic equipment

Info

Publication number: CN115802250A
Application number: CN202211397817.8A
Authority: CN
Inventors: 刘丁发; 蔡平; 方锂铭; 陈尚彬; 程巧玲; 王家磊
Original assignee: Jiangxi University Of Software Technology
Current assignee: Jiangxi University Of Software Technology
Priority date: 2022-11-09
Filing date: 2022-11-09
Publication date: 2023-03-14

Abstract

The invention belongs to the technical field of noise reduction treatment, and discloses a miniature indoor noise reduction electronic device, which can effectively capture vibration caused by original noise, convert the vibration into a signal, transmit the signal to an active noise reduction circuit and process the signal, send out reverse phase sound wave according to the original noise sound wave, and when the electronic device is attached to a window or a wall, the plane of the window is the same as a vibrating diaphragm of an earphone, feed back surrounding noise vibration to the device, and then the device reacts to generate phase frequency opposite to the noise, so that the noise reduction function is realized.

Description

Miniature indoor noise reduction electronic equipment

Technical Field

The invention belongs to the technical field of noise reduction treatment, and particularly relates to a miniature indoor noise reduction electronic device.

Background

The noise is the sound produced when the sounding body does irregular vibration. Sound is generated by the vibration of an object and propagates in a certain medium (e.g., solid, liquid, gas) in the form of waves. Noise pollution is commonly referred to as being artificially created. From a physiological point of view, all sounds that disturb people's rest, study and work and that interfere with the sound you hear, i.e. unwanted sounds, are collectively referred to as noise. Noise pollution is created when noise adversely affects people and the surrounding environment. Since the industrial revolution, the creation and use of various mechanical devices has brought prosperous and advanced to human beings, but at the same time, more and more noises are generated. The noise can not only cause damage to hearing, but also induce a plurality of carcinogenic and fatal diseases, and interfere the life and work of people.

The noise reduction treatment aspect can be roughly divided into active noise reduction and passive noise reduction. Most of passive noise reduction is to add sound insulation materials, so that the noise reduction effect is achieved. Although the method has simple principle and low noise reduction cost, the effect is slightly inferior, and the comfort level of wearing the earphone is reduced to some extent due to the use of the high-density sound insulation material. The sponge adopted by the closed earmuff type earphone has two noise reduction means of sound insulation and sound absorption, but the sponge cannot neutralize the noise due to lower sealing performance, so that the quiet listening effect is achieved. This may also allow the user to mask the noise by autonomously increasing the volume while wearing the headset. The advantage of passive noise reduction is that the noise reduction space is large, the isolation effect for high frequency signals is good, but for low frequency noise in a small space, the noise reduction effect is greatly reduced. Most of active noise reduction is to utilize anti-phase sound waves to offset noise sound waves, but the existing active noise reduction equipment is not flexible enough, cannot be adjusted according to noise frequency bands in time, and has certain limitation in noise reduction.

Disclosure of Invention

The invention aims to provide a miniature indoor noise reduction electronic device to solve the problems in the prior art in the background technology.

In order to achieve the purpose, the invention adopts the following technical scheme:

a miniature indoor noise reduction electronic device comprises a signal processing system and a signal processing unit, wherein the signal processing unit is loaded on the signal processing system: the vibration sensor is used for capturing vibration caused by original noise, converting the vibration into a signal and transmitting the signal to the active noise reduction circuit for processing; an active noise reduction system for emitting an anti-phase sound wave from an original noise sound wave; an acoustic system for controlling the frequency band of the antiphase sound wave according to the frequency band of the original noise sound wave;

the active noise reduction circuit comprises a pre-amplification circuit, a phase reversal circuit and a signal superposition amplification circuit, wherein the pre-amplification circuit, the phase reversal circuit and the signal superposition amplification circuit are connected.

Preferably, the pre-amplifying circuit is an operational amplifier circuit, and does not perform inverse processing on the audio, the gain of the pre-amplifying is determined by the ratio of R8 and R6, the amplitude of the audio signal can be controlled by changing the two resistance values, and the signal is sent to the phase inversion circuit.

Preferably, the phase inversion circuit changes the signal phase by changing the voltage polarity, and changes the amplitude of the operational amplifier circuit by changing the ratio of the resistors R12 and R10.

Preferably, the signal superposition amplifying circuit outputs the inverted noise signal and the inverted sound wave signal to the loudspeaker in a superposition mode, and the gain of the superposed signal is controlled by the ratio of R19 to R15.

Preferably, the active noise reduction system comprises a noise sensor for collecting noise signals, an error sensor for collecting error signals, a signal processor and a loudspeaker; and the noise sensor, the error sensor and the loudspeaker are all connected with the signal processor.

Preferably, the active noise reduction system further comprises a micro control computer, and the micro control computer is connected with the signal processor through a command output port and high-speed data transmission; the signal processor is connected with the control signal through a digital-to-analog converter, a smoothing filter and a power amplifier in sequence, and the noise signal and the error signal are connected with the signal processor through a preamplifier, an anti-folding filter and the digital-to-analog converter.

Preferably, the acoustic system comprises a signal generator, a power amplifier, a transducer, a microphone and an oscilloscope; the signal generator is connected with the transducer through the DSP system and the power amplifier, and the transducer is connected with the oscilloscope through the microphone and the signal acquisition equipment.

Preferably, the device also comprises a shell for installing a signal processing system, wherein the shell is internally connected with an integrated circuit board and a power supply, the vibration sensor, the active noise reduction circuit, the source noise reduction system and the acoustic system are all arranged on the integrated circuit board, and the back side of the shell is connected with a sucker for fixing the shell indoors.

Preferably, the inboard of casing is seted up and is used for connecting the mounting hole of vibrations sensor, the externally mounted of mounting hole has the rubber lid, the vibrations sensor is in the inside of rubber lid.

The invention has the technical effects and advantages that: compared with the prior art, the miniature indoor noise reduction electronic equipment provided by the invention has the following advantages:

the invention can effectively capture the vibration caused by the original noise by arranging the signal processing system, and the vibration sensor, the active noise reduction system and the acoustic system which are carried on the signal processing system, convert the vibration into a signal and transmit the signal to the active noise reduction circuit for processing, and send out the reverse phase sound wave according to the original noise sound wave, and in a certain space, when the electronic equipment is attached to a window or a wall, the plane of the window and the like is just like the vibrating diaphragm of an earphone, the vibration of the surrounding noise is fed back to the equipment, and then the equipment reacts to generate the phase frequency opposite to the noise, thereby playing the noise reduction function.

Drawings

FIG. 1 is a schematic diagram of a signal processing system according to the present invention;

FIG. 2 is a diagram of an active noise reduction circuit of the present invention;

FIG. 3 is a pre-amplifier circuit diagram of the present invention;

FIG. 4 is a phase inversion circuit diagram of the present invention;

FIG. 5 is a circuit diagram of signal superposition amplifier according to the present invention;

FIG. 6 is a schematic diagram of an active noise reduction system of the present invention;

FIG. 7 is a block diagram of an active noise reduction system of the present invention;

FIG. 8 is a circuit diagram of a digital signal processor according to the present invention

FIG. 9 is a block diagram of an acoustic system of the present invention;

fig. 10 is a schematic structural diagram of the miniature indoor noise reduction electronic device of the present invention.

In the figure: 1. a housing; 2. an integrated circuit board; 3. a suction cup; 4. mounting holes; 5. and a rubber cover.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The specific embodiments described herein are merely illustrative of the invention and do not delimit the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

An embodiment of the present invention provides a miniature indoor noise reduction electronic device, as shown in fig. 1, including a signal processing system and, mounted on the signal processing system: the vibration sensor is used for capturing vibration caused by original noise, converting the vibration into a signal and transmitting the signal to the active noise reduction circuit for processing; an active noise reduction system for emitting an anti-phase sound wave based on an original noise sound wave; an acoustic system for controlling the frequency band of the anti-phase sound wave according to the frequency band of the original noise sound wave;

as shown in fig. 2 to 5, the active noise reduction circuit includes a pre-amplification circuit, a phase reversal circuit, and a signal superposition amplification circuit, which are connected to each other. The pre-amplifying circuit is an operational amplifier circuit, and does not perform reverse processing on audio, the gain of pre-amplification is determined by the ratio of R8 to R6, the amplitude of an audio signal can be controlled by changing the two resistance values, and the signal is sent to the phase inversion circuit. The phase inversion circuit changes the signal phase by changing the voltage polarity, and changes the amplitude of the operational amplifier circuit by changing the ratio of the resistors R12 and R10. The signal superposition amplifying circuit superposes the inverted noise signal and the antiphase sound wave signal and outputs the superposed signals to a loudspeaker, and the gain of the superposed signals is controlled by the ratio of R19 to R15.

As shown in fig. 6 and 7, the active noise reduction system includes a noise sensor collecting a noise signal, an error sensor collecting an error signal, a signal processor, and a speaker; and the noise sensor, the error sensor and the loudspeaker are all connected with the signal processor.

The active noise reduction system also comprises a micro control computer, and the micro control computer is connected with the signal processor through a command output port and high-speed data transmission; the signal processor is connected with the control signal through a digital-to-analog converter, a smoothing filter and a power amplifier in sequence, and the noise signal and the error signal are connected with the signal processor through a preamplifier, an anti-folding filter and a digital-to-analog converter.

The active noise control is based on the principle of 2 sound wave destructive interference or sound wave radiation suppression, and 1 control sound source (secondary sound source) is artificially manufactured to make the sound emitted by the control sound source equal to the original noise source (primary sound source) in radiation noise and opposite in phase, so that the two action results are mutually offset, thereby achieving the purpose of noise reduction. The active noise control is based on the principle of 2 sound wave destructive interference or sound wave radiation suppression, and 1 control sound source (secondary sound source) is artificially manufactured to make the sound emitted by the control sound source equal to the original noise source (primary sound source) in radiation noise and opposite in phase, so that the two action results are mutually offset, thereby achieving the purpose of noise reduction.

The digital signal processor in the system selects a 16-bit fixed-point ADSP-2111 chip of AD company, the core structure of which is shown in figure 8 and has the following characteristics:

(1) The ADSP-2111 chip adopts a Harvard structure, 6 buses (1 program bus, 2 data buses, 2 address buses and 1 DMA bus) are arranged in the chip, and the separated program bus and data bus can allow instruction words (from a program memory) and operands (from a data memory) to be acquired simultaneously without mutual interference. Therefore, the instruction and the data can be prepared in 1 period at the same time, and the speed of a plurality of operations in digital signal processing is much higher than that of a common singlechip, which is very necessary for noise control with very high real-time requirement.

(2) ADSP-2111 employs pipelining to reduce instruction execution time. The execution of one instruction needs to pass through several stages of instruction fetching, decoding, operand fetching and execution, and the pipeline operation makes 4 different instructions in active state, which greatly improves the operation speed and embodies the superior performance of DSP. Meanwhile, the internal part of the system contains a hardware multiplication/accumulator, the parallel work of the multiplier and the accumulator is realized on hardware, and the operation of multiplying for 1 time and summing the running products can be completed in a single instruction cycle.

(3) ADSP-2111 is a chip with Host Interface HIP (Host Interface Port) and can be conveniently interfaced with a PC. The HIP is a parallel I/O port, allows ADSP-2111 to be a peripheral of host memory mapping, the operation speed is similar to the bus speed of ADSP-2111, and the loading of DSP program by the host and the data communication between the DSP are completed through the HIP interface.

Peripheral circuit of ADSP-2111 chip

(1) Filter design

Due to the existence of acoustic feedback, the detection microphone adopts capacitive unidirectional microphones MIC1 and MIC2 to pick up noise signals and error signals, and the signals are amplified by a triode and then are filtered. Before a/D conversion, 1 analog filter (i.e. anti-folding filter in fig. 2) needs to be set to pre-filter to limit the signal bandwidth, and remove high frequency components above 1/2 sampling frequency to prevent occurrence of spectrum aliasing. The noise in the system is low-frequency noise, so the anti-folding filter is a low-pass filter; after D/a conversion, 1 analog low-pass filter (i.e., a smoothing filter in fig. 2) is always connected to suppress high-frequency components, so that the staircase waveform becomes a smooth analog signal output. The anti-folding filter and the smoothing filter in the system both adopt a switch capacitor filter ICMF-10, 2 second-order filters are concealed, and the functions of filters such as high pass, low pass, band stop, full pass and the like can be realized through clock pulses provided from the outside and an external resistor, so that the system has strong universality and is applied to the low-pass characteristic.

(2) Design of digital-to-analog conversion

An AD1848 audio interface chip is employed. The ADC and the DAC with double paths and high performance are both directly controlled by ADSP-2111, and the sampling frequency is distributed between 5.5kHz and 48kHz, so that the requirements of an active noise reduction system can be met. The power amplifier adopts a low-frequency power amplifier TA7240AP, and a generated control signal drives a loudspeaker to finish the active noise reduction process.

As shown in fig. 9, the acoustic system includes a signal generator, a power amplifier, a transducer, a microphone, and an oscilloscope; the signal generator is connected with the transducer through the DSP system and the power amplifier, and the transducer is connected with the oscilloscope through the microphone and the signal acquisition equipment.

The self-demodulation signal test of the audio frequency directional system comprises the following general procedures that a signal generator generates a sine input signal, the sine input signal is subjected to signal processing by a DSP system calling various algorithms and then is output to a power amplifier for power amplification; the amplified signals are converted into ultrasonic signals by the transducer and are transmitted to the air; the ultrasonic wave generates high-directivity audible sound by self demodulation in the process of transmitting in the air; the microphone converts the sound pressure of the self-demodulation audible sound signal into an electric signal and inputs the electric signal into the signal acquisition equipment; displaying and collecting the electric signal converted from sound pressure by an oscilloscope, a dynamic signal analyzer or a computer, and storing the signal; the signal of the oscilloscope is led into a computer to directly analyze the test signal through audio signal processing software.

As shown in fig. 10, in order to facilitate the installation of the noise reduction electronic device on a glass or a vehicle window, in this embodiment, a housing 1 for installing a signal processing system is provided, an integrated circuit board 2 and a power supply are connected in the housing 1, the vibration sensor, the active noise reduction circuit, the source noise reduction system and the acoustic system are all provided on the integrated circuit board 2, and a suction cup 3 for fixing the housing 1 indoors is connected to the back side of the housing. The mounting hole 4 that is used for connecting the vibrations sensor is seted up to the inboard of casing 1, the externally mounted of mounting hole 4 has rubber lid 5, the vibrations sensor is in the inside of rubber lid 5.

When noise electronic equipment falls in the installation, adsorb at glass through sucking disc 3, perhaps on the door window, rubber lid 5 can compress and can hug closely at glass, perhaps on the door window, do benefit to the vibration sensor and receive the vibration, can have the effectual vibration that catches former noise and arouse, convert it into the signal after and send the initiative and fall the noise circuit and handle, send the anti-phase sound wave according to former noise sound wave, in certain space, when electronic equipment pastes window or wall, the window isoplane is just like the vibrating diaphragm of earphone, give equipment to the vibration feedback of noise on every side, equipment reacts after that, produce the phase frequency opposite with the noise, thereby play the function of making an uproar, when external noise grow, equipment effect also can strengthen, external noise becomes little, it also can corresponding adjustment to suitable degree come noise control.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments or portions thereof without departing from the spirit and scope of the invention.

Claims

1. The utility model provides a miniature indoor noise electronic equipment that makes an uproar which characterized in that: the device comprises a signal processing system and a signal processing unit, wherein the signal processing system is loaded with: the vibration sensor is used for capturing vibration caused by original noise, converting the vibration into a signal and transmitting the signal to the active noise reduction circuit for processing; an active noise reduction system for emitting an anti-phase sound wave based on an original noise sound wave; an acoustic system for controlling the frequency band of the anti-phase sound wave according to the frequency band of the original noise sound wave;

2. The miniature indoor noise reduction electronic device of claim 1, wherein: the pre-amplifying circuit is an operational amplifier circuit, and does not perform reverse processing on audio, the gain of pre-amplification is determined by the ratio of R8 to R6, the amplitude of an audio signal can be controlled by changing the two resistance values, and the signal is sent to the phase inversion circuit.

3. The miniature indoor noise reduction electronic device of claim 2, wherein: the phase inversion circuit changes the signal phase by changing the voltage polarity, and changes the amplitude of the operational amplifier circuit by changing the ratio of the resistors R12 and R10.

4. The miniature indoor noise reduction electronic device of claim 3, wherein: the signal superposition amplifying circuit superposes the inverted noise signal and the antiphase sound wave signal and outputs the superposed signals to a loudspeaker, and the gain of the superposed signals is controlled by the ratio of R19 to R15.

5. The miniature indoor noise reduction electronic device of claim 1, wherein: the active noise reduction system comprises a noise sensor for collecting noise signals, an error sensor for collecting error signals, a signal processor and a loudspeaker; and the noise sensor, the error sensor and the loudspeaker are all connected with the signal processor.

6. The miniature indoor noise reduction electronic device of claim 5, wherein: the active noise reduction system also comprises a micro control computer, and the micro control computer is connected with the signal processor through a command output port and high-speed data transmission; the signal processor is connected with the control signal through a digital-to-analog converter, a smoothing filter and a power amplifier in sequence, and the noise signal and the error signal are connected with the signal processor through a preamplifier, an anti-folding filter and the digital-to-analog converter.

7. The miniature indoor noise reduction electronic device of claim 6, wherein: the acoustic system comprises a signal generator, a power amplifier, a transducer, a microphone and an oscilloscope; the signal generator is connected with the transducer through the DSP system and the power amplifier, and the transducer is connected with the oscilloscope through the microphone and the signal acquisition equipment.

8. The miniature indoor noise reduction electronic device of claim 1, wherein: still including casing (1) that is used for installing signal processing system, be connected with integrated circuit board (2) and power in casing (1), vibration sensor, the circuit of making an uproar, source noise reduction system and acoustic system of falling all set up on integrated circuit board (2), just casing (1) dorsal part is connected with and is used for fixing its sucking disc (3) indoor.

9. The miniature indoor noise reduction electronic device of claim 8, wherein: the utility model discloses a vibration sensor, including casing (1), mounting hole (4) that are used for connecting the vibration sensor are seted up to the inboard of casing (1), the externally mounted of mounting hole (4) has rubber lid (5), the vibration sensor does the inside of rubber lid (5).