A sound level meter capable of eliminating steady-state interfering sounds

Abstract

The invention relates to a sound level meter capable of eliminating steady-state interference sound, comprising a shell, wherein a microphone, a preamplifier, an A / D converter, a memory, a sound separation module, an attenuator, an amplifier, a frequency weighting device, a detector, a sound channel, and a battery are arranged in the shell; a display screen and a control button are arranged on the shell, and a controller is also arranged in the shell, wherein the microphone, the preamplifier, the A / D converter, the memory, the sound separation module, the sound channel, the sound synthesis module, the attenuator, the amplifier, the frequency weighting device, and the detector are respectively connected to the controller for control; the display screen and the control button are respectively electrically connected to the controller; a charging port for charging the battery is arranged on the shell; while separating a mixed sound signal into sound units, steady-state interference noise can be separated from the mixed sound signal obtained by the sound level meter, so as to avoid interference of the interference noise on the acoustic environment monitoring.

Description

Technical Field

[0001] The invention belongs to the technical field of noise measurement, and in particular relates to a sound level meter capable of eliminating steady-state interference sounds. Background Art

[0002] The sound level meter is the most basic noise measuring instrument. It is an electronic instrument, but it is different from objective electronic instruments such as voltmeters. When converting sound signals into electrical signals, it can simulate the time characteristics of the human ear's reaction speed to sound waves; it has characteristics of different sensitivities and intensity characteristics of changing characteristics at different loudness. The sound level meter is a subjective electronic instrument.

[0003] In the prior art, the sound level meter generally includes a microphone, a preamplifier, an attenuator, an amplifier, a frequency weighting network, a detector, a display screen, a memory, a microcontroller, a power supply, etc. Its basic working principle is: the microphone transmits the sound information to the converter, the converter converts the sound signal into an electrical signal, and then the preamplifier transforms the impedance to match the microphone with the attenuator. The amplifier adds the output signal to the frequency weighting network, performs frequency weighting on the signal, and then amplifies the signal to a certain amplitude through the attenuator and the amplifier, and sends it to the effective value detector, and gives the value of the noise level on the indicator.

[0004] When conducting highway environmental monitoring, we often encounter situations where the monitoring data is distorted due to steady-state interference factors such as pedestrians talking, birds singing, and cicadas chirping around the monitoring points. This is especially true for cicadas, which last from June to October each year for several months. In addition, the trees along the highway are tall and dense, and the cicadas chirp one after another during the day, continuously, almost without interruption. Existing sound level meters can eliminate sudden noise during the detection period, but cannot eliminate steady-state interference noise. Therefore, when the above-mentioned interference factors exist, the monitoring data collected by the existing sound level meter is significantly distorted and cannot be used as an effective monitoring result, which seriously affects the accuracy of the monitoring data and the progress of the monitoring work. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a sound level meter capable of eliminating steady-state interference sounds, so as to solve the problem that the sound level meter in the prior art cannot eliminate steady-state interference noise, resulting in distortion of the collected detection data.

[0006] To achieve the above object, the technical solution adopted by a sound level meter capable of eliminating steady-state interference sound of the present invention is:

[0007] A sound level meter capable of eliminating steady-state interfering sounds, comprising:

[0008] case;

[0009] The shell is provided with a microphone, a preamplifier, an A / D converter, a memory, a sound separation module, a detector, a sound channel, a sound synthesis module, an attenuator, an amplifier, and a frequency weighting device;

[0010] Microphone is used to collect sound;

[0011] The preamplifier is used to amplify the sound collected by the microphone;

[0012] The A / D converter is used to convert the sound signal amplified by the preamplifier into a digital signal;

[0013] A plurality of sound samples are stored in the memory;

[0014] The sound separation module is used to filter the digital signal converted by the A / D converter, and compare it with the multiple sound samples stored in the memory, and separate the sound into sound units corresponding to the sound samples in the memory;

[0015] The sound units are stored in a memory;

[0016] The sound channel is used to display the sound unit on the display screen;

[0017] The sound synthesis module is used for synthesizing sound units;

[0018] Attenuators and amplifiers are used to adjust the digital signal of the synthesized sound;

[0019] The frequency weighter is used to divide the digital signal of the synthesized sound into different sound levels;

[0020] The housing is provided with a display screen and control buttons;

[0021] A controller is also provided in the housing;

[0022] The microphone, preamplifier, A / D converter, memory, sound separation module, detector, sound channel, sound synthesis module, attenuator, amplifier, and frequency weighting device are respectively connected to the controller for control;

[0023] The display screen and control buttons are respectively connected to the controller for control;

[0024] Battery: arranged in the housing, the battery is electrically connected to the controller to supply power to the controller;

[0025] The shell is provided with a charging port for charging the battery.

[0026] Beneficial effects: The sound level meter of the present invention can separate the mixed sounds of pedestrians talking, birds singing, cicadas chirping, etc. in the collected mixed sound signals to form sound units one by one when carrying out environmental monitoring, so that the steady-state interference noise can be separated from the monitored mixed sound signals while separating the mixed sound signals into sound units, thereby avoiding interference noise on the sound environment monitoring results, screening the sound units through the sound channel, and then synthesizing the retained sound units through the sound synthesis module, and then adjusting the synthesized sound through the attenuator and the amplifier so that the synthesized sound can match the frequency weighter, so that the frequency weighter performs frequency weighting on the synthesized sound (mixed sound with interference sound removed), and the result is displayed on the display screen; the authenticity, validity and accuracy of the monitoring data collected by the sound level meter are ensured, and the monitoring work is ensured to have high efficiency.

[0027] Furthermore, it also includes a D / A converter and a speaker. The D / A converter is used to convert the digital signal in the sound channel into a sound signal. The speaker is used to play the sound signal converted by the D / A converter. The D / A converter and the speaker are respectively connected to the controller.

[0028] Beneficial effects: The arrangement of the D / A converter and the loudspeaker can further ensure the audition of the separated sound unit, so as to delete the mixed interference sound in the mixed sound signal collected by the sound level meter based on the audition.

[0029] The microphone is arranged above the shell and protrudes from the shell.

[0030] Beneficial effect: It can facilitate the microphone to collect sound better.

[0031] The end of the microphone is sleeved with sound-absorbing cotton.

[0032] Beneficial effect: Ensure that the microphone has better sound collection effect.

[0033] The controller is a single chip microcomputer.

[0034] Beneficial effect: It is economical and practical to use a single chip microcomputer as a controller of a sound level meter. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the connection structure of a controller and various components of a sound level meter capable of eliminating steady-state interference sounds according to the present invention;

[0036] Figure 2 It is a logic block diagram of a sound level meter capable of eliminating steady-state interfering sounds of the present invention;

[0037] Figure 3 The present invention discloses a display interface of a sound level meter capable of eliminating steady-state interference sounds;

[0038] Figure 4 It is a display interface of a sound level meter capable of eliminating steady-state interference sounds during operation of the present invention;

[0039] Figure 5 The present invention is a structural schematic diagram of a sound level meter capable of eliminating steady-state interference sounds.

[0040] Figure numerals: 1-shell; 2-sound-absorbing cotton; 3-display screen; 4-speaker; 5-control button. DETAILED DESCRIPTION

[0041] The following is a further detailed description of a sound level meter capable of eliminating steady-state interference sounds according to the present invention in conjunction with the accompanying drawings and specific embodiments:

[0042] like Figure 1 , Figure 2 , Figure 5 As shown, a sound level meter capable of eliminating steady-state interference sound of the present invention comprises a rectangular housing 1, in which a microphone is arranged. In this embodiment, the microphone is used to collect sound. In order to facilitate the microphone to collect sound, the microphone is arranged on the top of the housing 1 and protrudes from the housing 1. The end of the microphone away from the housing 1 is a spherical body, and a sound-absorbing cotton 2 is covered on the spherical body so that the microphone has a better sound collection effect. In this embodiment, the microphone is a condenser microphone, and its model is RODE NT55.

[0043] A display screen 3, a speaker 4, and a control button 5 are arranged in sequence from top to bottom on the front side of the housing 1. The control button 5 includes a switch button for controlling the start and stop of the sound level meter, and up, down, left, right, and confirm buttons for selecting sound channels.

[0044] A preamplifier is arranged in the housing 1, and the preamplifier is used to amplify the mixed sound signal collected by the microphone. The model of the amplifier is SXO-4Q.

[0045] An A / D converter is arranged in the housing 1, and the A / D converter is used to convert the mixed sound signal amplified by the preamplifier into a digital signal.

[0046] A memory is provided in the housing 1, and a plurality of sound samples are stored in the memory. In this embodiment, the plurality of sound samples include bird calls, cicada calls, human speech sounds, etc., and the plurality of sound samples are stored in the memory in the form of digital signals.

[0047] A sound separation module is provided in the housing 1, and the sound separation module is used to filter the digital signal converted by the A / D converter, and compare the collected mixed sound with the sound sample in the memory, and separate the sound into sound units corresponding to the sound sample in the memory, and the sound units are stored in the memory. The sound separation module in the present invention is a prior art, such as the mixed sound separation device described in the authorization announcement number CN100585701C, which will not be described in detail here.

[0048] like Figure 3 and Figure 4 As shown, multiple sound channels are arranged in the housing 1, and the sound channels are arranged on the display screen. Under the control of the controller, the sound channels are used to intuitively display the various sound units separated by the sound separation module. In addition, the sound channels can filter the sound units. Specifically, when the sound channel operation button is clicked, two secondary buttons "listen" and "shield" pop up on the display screen. When the "listen" button is clicked, the sound of the channel can be listened to. When the "shield" button is clicked, the sound of the channel can be shielded. After the sound channel is shielded, it will no longer participate in the sound level calculation of the subsequent process.

[0049] A D / A converter is provided in the housing 1, and the D / A converter is used to convert the digital signal of the sound unit in the sound channel into a sound signal, so as to provide conditions for the playing of the sound unit in the sound channel.

[0050] A speaker is also provided in the shell. Under the action of the controller, when the "listen" button is clicked, the sound unit passing through the D / A converter is played through the speaker. By playing the sound unit, it is determined whether the sound unit is an interference sound. If the sound unit is determined to be an interference sound, the sound unit is shielded by clicking the shielding button.

[0051] A sound synthesis module is provided in the shell, and the sound synthesis module is used to synthesize the sound units after being screened by the sound channel. In this embodiment, the sound synthesis module is used to synthesize the retained sound units, and the digital signal of the synthesized sound is stored in the memory; the sound synthesis module is a prior art and will not be described in detail here.

[0052] An attenuator and an amplifier are provided in the housing 1, which can adjust the digital signal of the synthesized sound, for example, amplify the digital signal that the frequency weighter cannot distinguish, and attenuate the digital signal that exceeds the reference of the frequency weighter, so as to facilitate the frequency weighter to process the digital signal of the sound. The model of the attenuator is MAATCC0005, and the model of the amplifier is BUF602.

[0053] A frequency weighting device is arranged in the housing 1, and the frequency weighting device is used to divide the digital signal of the synthesized sound adjusted by the attenuator and the amplifier into different sound levels. In this embodiment, the common frequency weighting devices (frequency weighting networks) in the sound level meter include four standard weighting networks A, B, C, and D: the A network simulates the response of the human ear to the frequency characteristics of low-intensity noise below 55 dB (i.e., to 40 fang pure tone in the equal loudness curve), and its noise meter curve shape is opposite to the equal loudness curve of 340 fang, so that the medium and low frequency bands of the electrical signal have a large attenuation; the B network simulates the response of the human ear to the frequency characteristics of medium-intensity noise of 55 dB to 85 dB (i.e., to 70 fang pure tone in the equal loudness curve), which causes a certain attenuation in the low frequency band of the electrical signal; the C network simulates the response of the human ear to the frequency characteristics of high-intensity noise of 85 dB to 120 dB (i.e., to 100 fang pure tone in the equal loudness curve), and has a nearly flat response in the entire audio frequency range; the D weighted sound level is a simulation of noise parameters and is specifically used for the measurement of aircraft noise.

[0054] The so-called "frequency weighting network" refers to the use of certain filter networks on the measuring instrument to attenuate sound signals of different frequencies to varying degrees based on the equal loudness curve, correcting the electrical signal to an approximate value that matches the hearing sense, so that the instrument reading can approximately express the human response to sound. This network is called a frequency weighting network.

[0055] The sound pressure level measured by the weighting network is no longer an objective physical quantity, but is called weighted sound pressure level or weighted sound level, or sound level for short.

[0056] A detector is arranged in the housing 1, and the detector is used to adjust the digital signal of the frequency-weighted synthesized sound. The model of the detector is AD637.

[0057] A controller is provided in the housing 1. In the present embodiment, the controller is an STMicroelectronics STM32F103ZET6 single chip microcomputer; a microphone, a preamplifier, an A / D converter, a memory, a sound separation module, a sound channel, a sound synthesis module, an attenuator, an amplifier, a frequency weighting device, a detector, a D / A converter, and a speaker 4 are respectively connected to the controller for control; a display screen 3 and a control button 5 are also connected to the controller for control.

[0058] A battery is arranged in the housing 1 , and the battery is electrically connected to the controller for supplying power to the controller. A charging port for charging the battery is arranged on the housing 1 .

[0059] When the sound level meter of the present invention is used, the condenser microphone collects mixed sounds at the monitoring site, and under the action of the controller, the mixed sound signal is transmitted to the preamplifier, the preamplifier amplifies the collected mixed sound signal, and then transmits it to the A / D converter, and the sound data is converted into a digital signal through the A / D converter. The sound separation module reads the digital signal converted by the A / D converter and performs filtering processing. Moreover, under the action of the controller, the sound separation module compares the digital signal of the mixed sound with the sound sample in the memory, and separates the mixed sound into sound units corresponding to the sound sample in the memory. At this time, a plurality of sound units will be formed, and the plurality of sound units are stored in the memory.

[0060] Under the control of the controller, the digital signal of the sound unit can enter the corresponding sound channel. In this embodiment, each sound channel is displayed on the display screen.

[0061] Under the action of the controller, the digital signal of the sound unit in the sound channel is converted into a sound signal through the D / A converter, and the sound signal can be played through the speaker to audition the separated sound unit. The sound channel screens each sound unit, such as Figure 3 and Figure 4 As shown, when the control button selects a certain sound channel, the sound channel will display two dialog boxes, namely, audition and shielding, under the action of the controller.

[0062] Select the audition dialog box, and the sound unit in the sound channel will be played through the speaker. When the speaker plays the sound unit in the sound channel, human hearing is used to further determine whether the sound unit is an interference sound. If the judgment result is that the sound unit is not an interference sound, do not click the "Shield" button, the sound unit will be retained and participate in the subsequent sound level calculation; if the judgment result is that the sound unit is an interference sound, select the "Shield" button, the sound unit will be shielded from the sound channel and will not participate in the subsequent sound level calculation.

[0063] Under the action of the controller, the unshielded (retained) sound units are synthesized into a sound signal through the sound synthesis module, and the synthesized sound is stored in the memory. Under the action of the controller, the synthesized sound is adjusted by the attenuator and the amplifier; then the digital signal of the synthesized sound enters the frequency weighting device, and the frequency weighting device performs subsequent calculations on the digital signal of the synthesized sound to form sound level data displayed on the display screen.

[0064] The sound level meter of the present invention can perform sound separation on the collected sound signal, then eliminate the interference sound in the collected sound signal, and then synthesize the retained sound units, the synthesized sound is the sound signal without the interference sound, and then the sound level of the sound signal after the interference is eliminated is calculated, so that the synthesized sound of the calculated sound level is closer to the ideal sound signal (excluding the interference sound), thereby ensuring that the calculated sound level is more accurate, ensuring the authenticity, validity and accuracy of the monitoring data collected by the sound level meter, and thus making the monitoring work more efficient.

[0065] In the above embodiment, a D / A converter and a speaker are also included. The D / A converter is used to convert the digital signal in the sound channel into a sound signal, and the speaker is used to play the sound signal converted by the D / A converter. The D / A converter and the speaker are respectively connected to the controller control. In other embodiments, the D / A converter and the speaker may not be set. In this case, the mixed sound signal is separated and the sound level is divided only through the sound separation module.

[0066] In the above embodiments, the microphone is arranged on the top of the shell and protrudes from the shell; in other embodiments, the microphone is arranged on the top of the shell and is flush with the top of the shell.

[0067] In the above embodiment, the end of the microphone is provided with sound-absorbing cotton; in other embodiments, the sound-absorbing cotton may not be provided.

[0068] In the above embodiment, the controller is a single-chip microcomputer; in other embodiments, the controller may also be an ARM architecture low-power processor, such as Huawei KIRIN series, Qualcomm 800 series, and 700 series processors. Accordingly, if the above processors are used, the sound level meter operating system will also be changed to an operating system that supports the above CPU.

Claims

1. A sound level meter capable of eliminating steady-state interfering sounds, characterized in that: include: case; The shell is provided with a microphone, a preamplifier, an A / D converter, a memory, a sound separation module, a sound channel, a sound synthesis module, an attenuator, an amplifier, a frequency weighting device, and a detector; Microphone is used to collect sound; The preamplifier is used to amplify the sound collected by the microphone; The A / D converter is used to convert the sound signal amplified by the preamplifier into a digital signal; A plurality of sound samples are stored in the memory; The sound separation module is used to filter the digital signal converted by the A / D converter, and compare it with the multiple sound samples stored in the memory, and separate the sound into sound units corresponding to the sound samples in the memory; The sound units are stored in a memory; The sound channel is used to display the sound units on the display screen and filter the sound units; The sound synthesis module is used for synthesizing the retained sound units; Attenuators and amplifiers are used to adjust the digital signal of the synthesized sound; The frequency weighter is used to divide the digital signal of the synthesized sound into different sound levels; The housing is provided with a display screen and control buttons; A controller is also provided in the housing; The microphone, preamplifier, A / D converter, memory, sound separation module, sound channel, sound synthesis module, attenuator, amplifier, frequency weighting device, and detector are respectively connected to the controller for control; The display screen and control buttons are respectively connected to the controller for control; Battery: arranged in the housing, the battery is electrically connected to the controller and is used to supply power to the controller; The housing is provided with a charging port for charging the battery; It also includes a D / A converter and a speaker, the D / A converter is used to convert the digital signal in the sound channel into a sound signal, the speaker is used to play the sound signal converted by the D / A converter, and the D / A converter and the speaker are respectively connected to the controller for control; The microphone is arranged on the top of the housing and protrudes from the housing; The controller is a single chip microcomputer.

2. A sound level meter capable of eliminating steady-state interference sound according to claim 1, characterized in that: The end of the microphone is covered with sound-absorbing cotton.

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