CN112146746B - Sound level metering method and sound level meter - Google Patents
Sound level metering method and sound level meter Download PDFInfo
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Abstract
The application provides a sound level metering method and a sound level meter, wherein the method comprises the following steps: gain adjustment is carried out on the sound signal through a gain unit to obtain a gain signal; filtering the gain signal through a filter to obtain a filtered signal; performing analog-to-digital conversion on the filtered signal to obtain a sound digital signal; and calculating the A frequency weighting coefficient of the sound digital signal to obtain the sound level corresponding to the sound signal. By the sound level metering method and the sound level meter, the sound processing difficulty can be reduced.
Description
Technical Field
The application relates to the technical field of sound level meters, in particular to a sound level metering method and a sound level meter.
Background
A sound level meter is a measuring instrument that detects the intensity of sound. The frequency weighting mode of the sound level meter is frequency weighting A. The A frequency weighting is a band-pass filter simulating the auditory supervisor of human ears, and is greatly different from the filter of a common digital or analog circuit. The conventional A frequency weighting filter of the sound level meter comprises: the method is realized by an analog circuit: decomposing a weighted frequency domain filter characteristic A; the complicated analog circuit has complicated production and processing and large volume, and in addition, the consistency is poorer due to the existence of precision errors of a plurality of resistors and capacitors of the filter of the separating device.
Disclosure of Invention
The application aims to provide a sound level metering method and a sound level meter, which can reduce the difficulty of sound processing.
In a first aspect, an embodiment of the present invention provides a sound level metering method, including:
gain adjustment is carried out on the sound signal through a gain unit to obtain a gain signal;
filtering the gain signal through a filter to obtain a filtered signal;
performing analog-to-digital conversion on the filtered signal to obtain a sound digital signal;
and calculating the A frequency weighting coefficient of the sound digital signal to obtain the sound level corresponding to the sound signal.
In an optional embodiment, the calculating the a-frequency weighting coefficient on the sound digital signal to obtain a sound level corresponding to the sound signal includes:
carrying out frequency domain conversion processing on the sound digital signal to obtain frequency domain data;
correcting the A frequency weighting coefficient of the frequency domain data to obtain a frequency domain power spectrum;
calculating the total power of the frequency domain according to the frequency domain power spectrum;
and calculating the sound level corresponding to the sound signal according to the frequency domain total power.
In the above embodiment, the calculation of the weighting coefficient of the frequency a is performed in a digital calculation manner, so that the structure of a hardware circuit in the sound level meter can be reduced, and thus, an error with poor consistency due to an existing precision error of a resistance capacitor can be reduced, and the accuracy of the determined sound level of the sound level meter can be improved.
In an optional embodiment, the frequency domain converting the sound digital signal to obtain frequency domain data includes:
and carrying out fast Fourier transform processing on the sound digital signal to obtain frequency domain data.
In the above embodiment, the frequency domain data obtained based on the fast fourier transform may provide a data basis for the subsequent a-frequency weighting coefficient correction, and further, the transform is performed by the fast fourier transform, so that the calculation amount is relatively small, and the calculation efficiency may also be improved.
In an optional embodiment, the performing a-frequency weighting coefficient correction on the frequency-domain data to obtain a frequency-domain power spectrum includes:
and performing weighting calculation on the frequency domain data by using the pre-calculated A frequency correction coefficient to obtain a frequency domain power spectrum.
In the above embodiment, the frequency domain data is corrected based on the pre-calculated a-frequency correction coefficient, so that the frequency response of the determined a-weight can be made closer to the frequency response of the ideal a-weight, and the a-weight can be made more accurate.
In an optional embodiment, the calculating the total power in the frequency domain according to the power spectrum in the frequency domain includes:
and accumulating and summing the frequency domain power spectrums to obtain the frequency domain total power.
In an optional embodiment, the calculating, according to the total power in the frequency domain, a sound level corresponding to the sound signal includes:
and calculating the sound level corresponding to the sound signal according to the real value in the frequency domain total power.
In the above embodiment, the sound level corresponding to the sound signal can be obtained based on the calculation of the real value in the total power of the frequency domain, which is convenient for testing to obtain the digitized display of the sound level.
In an optional embodiment, the filtering the gain signal by a filter to obtain a filtered signal includes:
and filtering the gain signal through a second-order Bessel high-pass filter to obtain a filtered signal.
In the above embodiment, the second-order bessel high-pass filter is used for filtering, so that optimal filtering data can be obtained, and furthermore, sound level data obtained by measurement can be more accurate.
In a second aspect, an embodiment of the present invention provides a sound level meter, including: an analog domain unit and a digital domain unit;
the analog domain unit includes: a gain adjustment module and a filter;
the gain adjustment module is used for performing gain adjustment on the sound signal to obtain a gain signal;
the filter is used for filtering the gain signal to obtain a filtered signal;
the digital domain unit includes: the analog-to-digital conversion module and the data processing module;
the analog-to-digital conversion module is used for performing analog-to-digital conversion on the filtering signal to obtain a sound digital signal;
and the data processing module is used for calculating and processing the A frequency weighting coefficient of the sound digital signal to obtain a sound level corresponding to the sound signal.
In an alternative embodiment, the data processing module comprises: the device comprises a conversion submodule, a correction submodule, a first calculation submodule and a second calculation submodule;
the conversion submodule is used for carrying out frequency domain conversion processing on the sound digital signal to obtain frequency domain data;
the correction submodule is used for correcting the A frequency weighting coefficient of the frequency domain data to obtain a frequency domain power spectrum;
the first calculating submodule is used for calculating the total power of the frequency domain according to the frequency domain power spectrum;
and the second calculating submodule is used for calculating the sound level corresponding to the sound signal according to the total power of the frequency domain.
In an alternative embodiment, the filter is a second order bessel high pass filter.
The beneficial effects of the embodiment of the application are that: by increasing the gain unit and the processing of multiple signals of the filter, the filtering calculation required in the calculation processing stage is reduced, so that the calculation efficiency of A frequency weighting can be improved, the hardware requirement of the sound level meter can be reduced, and the development difficulty of the sound level meter can be reduced.
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In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.
Fig. 1 is a block schematic diagram of a first prior art sound level meter.
Fig. 2 is a block schematic diagram of a second type of prior art sound level meter.
Fig. 3 is a block schematic diagram of a sound level meter provided in an embodiment of the present application.
Fig. 4 is a flowchart of a sound level metering method provided in an embodiment of the present application.
Detailed Description
The technical solution in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.
A sound level meter is a measuring instrument that detects the intensity of sound. According to the standard, the sound signal needs to be frequency weighted filtered before being measured in intensity to simulate the human auditory perception. Two types of frequency weighting are commonly used, one is a frequency weighting and the other is a C frequency weighting. Where a frequency weights are the ones that the standard specifies must support. Since the A frequency weighting filter is a band-pass filter simulating the auditory supervisor perception of human ears, the A frequency weighting filter has a larger difference with the filter of a common digital or analog circuit.
The inventor researches the A frequency weighting filter of the sound level meter to know that the following two A frequency weighting filters are analyzed:
as shown in fig. 1, the first type of sound level meter a frequency weighting filter is implemented by analog circuitry, and the first type of sound level meter a frequency weighting filter is fitted by six analog filters. In the example shown in fig. 1, the sound level meter includes: the device comprises a gain unit, six filters, an analog-to-digital conversion unit, a time domain power estimation module and a decibel conversion unit. The decibel conversion unit is used for converting the signal into a decibel value.
Wherein, the six analog filters comprise a high-pass filter and a low-pass filter. Decomposing the A weighted frequency domain filtering through six filters, wherein in the using process, an input signal sequentially passes through: a low pass filter with a cutoff frequency of 12.2 KHz; a low pass filter with a cutoff frequency of 12.2 KHz; a high pass filter with a cut-off frequency of 20.6 Hz; a high pass filter with a cut-off frequency of 20.6 Hz; a high pass filter with a cutoff frequency of 107.7 Hz; six filters, such as a high pass filter with a cutoff frequency of 737.9 Hz. The first scheme sound level meter A frequency weighting filter: due to the complex analog circuit, the hardware cost is high, the production and processing are complex, the size is large, in addition, due to the filter of the separating device, the consistency ratio is poor due to the existence of precision errors of a plurality of resistors and capacitors, the consistency in batch production is poor, and the cost of qualified products is further improved.
As shown in fig. 2, the second type of frequency weighting filter for a sound level meter is implemented by a Digital Signal Processor (DSP), and the frequency weighting is performed in a Digital domain. In the example shown in fig. 2, the sound level meter includes: the system comprises a gain unit, an analog-to-digital conversion unit, a multi-stage IIR (Infinite Impulse Response, Chinese called: Infinite Impulse Response) filter, a time domain power estimation module and a decibel conversion unit.
The second sound level meter a frequency weighting filter needs to filter the digital signal after analog-to-digital conversion (a/D) through a high-speed DSP dedicated processing chip.
The second sound level meter A frequency weighting filter is realized by a digital filter, and a multistage IIR filter is used for fitting the A frequency weighting. The calculation of the digital filtering of the IIR involves a total of 22 parameters. The IIR filter of the A frequency weighting filter of the second sound level meter has more orders and complex structure, and has high requirements on the processing speed and the memory of a digital DSP. Therefore, the frequency weighting filter of the second sound level meter a requires a developer with strong programming capability of DSP digital signal processing to implement a high-order DSP algorithm, resulting in a long development period, high development difficulty, and an increase in the overall cost of the sound level meter.
Based on the above research, the embodiments of the present application provide a sound level measuring method and a sound level meter, which can improve the efficiency and the calculation efficiency of the sound level meter without requiring many digital calculation requirements under the condition of reducing the circuit structure in the analog domain. The sound level metering method and the sound level meter provided by the embodiment of the application are described by several embodiments.
Example one
The embodiment of the present application provides a sound level meter, as shown in fig. 1, the sound level meter in the embodiment includes: an analog domain unit 100 and a digital domain unit 200.
In this embodiment, the analog domain unit 100 includes: a gain adjustment module 110 and a filter 120.
The gain adjustment module 110 is configured to perform gain adjustment on the sound signal to obtain a gain signal.
The filter 120 is configured to perform a filtering process on the gain signal to obtain a filtered signal.
In this embodiment, the low frequency signal is filtered by the filter 120, so as to fit the low frequency response part data calculated by the a frequency.
Alternatively, the filter 120 may be a high pass filter for filtering the low frequency signal.
In one example, the high pass filter may be a second order bessel high pass filter. For example, the high pass filter may be a second order Bezier high pass filter at 89 Hz. Among them, the Bessel filter is a linear filter having a maximally flat group delay (linear phase response).
In the embodiment of the present application, only one filter 120 is provided in the analog domain unit 100, so that the analog circuits required in the sound level meter can be reduced, and the hardware cost is lower. Because the structure in the analog circuit is simple, the resistance capacitance in the circuit is less, and the problem of poor consistency caused by the precision error of the resistance capacitance can be reduced.
In this embodiment, the digital domain unit 200 includes: an analog-to-digital conversion module 210 and a data processing module 220.
In this embodiment, the analog-to-digital conversion module 210 is configured to perform analog-to-digital conversion on the filtered signal to obtain a sound digital signal.
The filtered signal is converted into a digital signal by the above-mentioned analog-to-digital conversion module 210, so as to facilitate the processing of the digital signal by the data processing module 220 in the digital domain unit 200.
Illustratively, as shown in fig. 3, the analog-to-digital conversion module 210 may be implemented by an analog-to-digital converter (a/D).
In this embodiment, the data processing module 220 is configured to perform calculation processing on the digital sound signal by using a frequency weighting coefficient to obtain a sound level corresponding to the sound signal.
In this embodiment, the data processing module 220 includes: a frequency domain conversion sub-module 221, a modification sub-module 222, a first calculation sub-module 223, and a second calculation sub-module 224.
The frequency domain conversion sub-module 221 is configured to perform frequency domain conversion processing on the sound digital signal to obtain frequency domain data;
the correction submodule 222 is configured to perform a frequency weighting coefficient correction on the frequency domain data to obtain a frequency domain power spectrum;
the first calculating submodule 223 is configured to calculate a frequency domain total power according to the frequency domain power spectrum;
the second calculating submodule 224 is configured to calculate a sound level corresponding to the sound signal according to the total power of the frequency domain.
In this embodiment, as shown in fig. 3, the frequency domain converting sub-module 221 may be a fast fourier transform module, configured to perform a fast fourier transform process on the sound digital signal to obtain frequency domain data.
Optionally, the modification sub-module 222 is further configured to perform a weighting calculation on the frequency-domain data by using a pre-calculated a-frequency modification coefficient to obtain a frequency-domain power spectrum.
Optionally, the first calculating sub-module 223 is configured to perform cumulative summation on the frequency domain power spectrums to obtain a frequency domain total power.
Optionally, the second calculating sub-module 224 is configured to calculate, according to the real value in the total power of the frequency domain, a sound level corresponding to the sound signal.
Optionally, the sound level meter may further comprise a memory and a processor.
In this embodiment, each module in the digital domain unit 200 may be a software functional module. The various modules in the digital domain unit 200 are stored in the memory. The processor can realize the processing of the sound signals after calling each module in the memory so as to obtain the sound level corresponding to the sound signals.
The processor may be an integrated circuit chip having signal processing capabilities. The Processor may be a general-purpose Processor, and includes a Central Processing Unit (CPU), a Network Processor (NP), and the like. Of course, the device may also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. The various methods, steps, and logic blocks disclosed in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The sound level meter provided by the embodiment can realize the measurement of the sound level of the sound signal. The procedure of sound level gauging is described below by way of a sound level gauging method embodiment.
Example two
Please refer to fig. 4, which is a flowchart illustrating a sound level measuring method according to an embodiment of the present disclosure. The specific flow shown in fig. 4 will be described in detail below.
Optionally, the gain signal may be filtered by a second-order bessel high-pass filter to obtain a filtered signal.
Illustratively, the first frequency response function of the hyperquadratic bessel high-pass filter may be expressed as:H B (f)。
Alternatively, a 48KHZ sampling frequency may be used for analog-to-digital conversion.
And 304, calculating the A frequency weighting coefficient of the sound digital signal to obtain a sound level corresponding to the sound signal.
Optionally, step 304 may include the following steps.
Step 3041, perform frequency domain conversion on the sound digital signal to obtain frequency domain data.
Alternatively, the step 3041 may: and performing Fast Fourier Transform (FFT) processing on the sound digital signal to obtain frequency domain data.
Alternatively, the sound digital signal may be calculated using a 2048-point FFT operation to obtain frequency domain data.
Step 3042, the frequency domain data is modified by the a frequency weighting coefficient to obtain the frequency domain power spectrum.
The sound level measuring method in the embodiment is used for weighting the frequency a, so that only the weighting coefficient of the frequency a can be modified in the data correcting time. Alternatively, the frequency domain data may be weighted using pre-calculated a frequency correction coefficients to obtain a frequency domain power spectrum.
In one example, the second frequency response functionH A’ (f)The frequency of the A frequency correction coefficient of (1) can be sequentially increased from 0Hz, and the frequency interval between two adjacent values is 23.3999 Hz. Illustratively, theH A’ (f)The correction coefficients may comprise power spectrum coefficients of 1024 frequency bins.
In this embodiment, an ideal a-weighted frequency response can be obtained through filtering by the second-order bessel high-pass filter and correcting the a-frequency correction coefficient, and is represented as:
wherein,H AC (f)representing the ideal a-weighted frequency response,H B (f)the implementation is carried out in the analog domain,H A’ (f)implemented in the digital domain.
Step 3043, calculating the total power of the frequency domain according to the frequency domain power spectrum.
In this embodiment, the frequency domain power spectrums are accumulated and summed to obtain the frequency domain total power.
Step 3044, calculating a sound level corresponding to the sound signal according to the total power of the frequency domain.
In this embodiment, the sound level corresponding to the sound signal is calculated according to the real value in the frequency domain total power.
The steps can only use a few filters in the analog domain, and the sound level measurement can be realized without using filters in the digital domain. In order to make the metered sound level more accurate, the a frequency correction coefficients of the first frequency response of the filter in the analog domain and the second frequency response function in the digital domain can also be determined by simulation in the following way.
In the embodiment of the present application, the frequency response of the ideal A weightH AC (f)At a first frequencyResponse functionH B (f)And a second frequency response functionH A’ (f)The influence of (c). The first frequency response functionH B (f)Including a parametric cut-off frequencyf T Order of degreek. Second frequency response functionH A’ (f)Of (2) matrixA ’ = [A f0 ,A f1 , …, A fn ],A fn The coefficients corresponding to the quantized frequency point frequency are, in this embodiment, matricesA ’ It can start from 0Hz and increase sequentially, and the frequency interval between two adjacent values is 23.3999 Hz.
According to the variables, the mean square error function of the A rate can be determined as a formula:
to minimize the error, the a frequency correction coefficients for the first frequency response and the second frequency response function in the digital domain may then be calculated as: when the calculation formula is minimized
The value taking process of (1).
In one embodiment, the minimum mean square error method can be solved by the following equation:
in another embodiment, the gradient can be obtained by iterative calculation of computer simulation through a fastest gradient descent method
The value of (a).
In this embodiment, the iterative stepping may be set according to actual calculation requirements.
In one example, k = [1, 2 ] may be selected], f T Andf n <the calculation is carried out at 300Hz,A fn (fn>= 300Hz) is fixed as the frequency response coefficient of the ideal a rate.
Based on the error minimization calculation, it is achieved that the first frequency response function required in the analog domain can pass through a 89Hz second order bessel filter.
In the sound level meter provided by the embodiment of the application, only one filter is used in the analog domain, and the number of the filters is far smaller than that of the six filters in the conventional scheme, so that the structure of the analog circuit part of the sound level meter provided by the embodiment of the application can be simpler. Further, since the digital domain part omits a multi-order filter, the processing capability requirement of the processor can be low, for example, a general low-speed embedded CPU can be used to process data. Because a common sound level meter has a general embedded CPU to process key input and display. Therefore, the calculations in step 303 and step 304 in the sound level metering method provided by the embodiment of the present application may be performed by a low-speed general-purpose embedded CPU in the current sound level meter. Therefore, through the sound level metering mode provided by the embodiment of the application, the calculation efficiency of A frequency weighting is increased, the hardware requirement of the sound level meter can be reduced, and the development difficulty of the sound level meter can be reduced. Further, the sound level meter has smaller volume and better consistency due to less hardware.
Furthermore, the present application also provides a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a processor to execute the steps of the sound level metering method described in the above method embodiments.
The computer program product of the sound level metering method provided in the embodiment of the present application includes a computer-readable storage medium storing a program code, where instructions included in the program code may be used to execute the steps of the sound level metering method in the foregoing method embodiment, which may be referred to in the foregoing method embodiment specifically, and are not described herein again.
In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented in other ways. The apparatus embodiments described above are merely illustrative, and for example, the flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
In addition, functional modules in the embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.
The functions, if implemented in the form of software functional modules and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes. It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (6)
1. A sound level metering method is applied to a sound level meter, the sound level meter comprises an analog domain unit and a digital domain unit, the digital domain unit is realized by an embedded CPU, and the sound level metering method comprises the following steps:
gain adjustment is carried out on the sound signal through a gain unit to obtain a gain signal;
filtering the gain signal through a second-order Bessel high-pass filter in the analog domain unit to obtain a filtered signal;
performing analog-to-digital conversion on the filtering signal through an analog-to-digital conversion module in a digital domain unit to obtain a sound digital signal;
carrying out frequency domain conversion processing on the sound digital signal through a data processing module in a digital domain unit to obtain frequency domain data; correcting the A frequency weighting coefficient of the frequency domain data to obtain a frequency domain power spectrum; calculating the total power of the frequency domain according to the frequency domain power spectrum; and calculating the sound level corresponding to the sound signal according to the frequency domain total power.
2. The method of claim 1, wherein the subjecting the sound digital signal to a frequency domain conversion process to obtain frequency domain data comprises:
and carrying out fast Fourier transform processing on the sound digital signal to obtain frequency domain data.
3. The method of claim 1, wherein said performing a-frequency weight coefficient modification on said frequency domain data to obtain a frequency domain power spectrum comprises:
and performing weighting calculation on the frequency domain data by using the pre-calculated A frequency correction coefficient to obtain a frequency domain power spectrum.
4. The method of claim 1, wherein said calculating a frequency domain total power from said frequency domain power spectrum comprises:
and accumulating and summing the frequency domain power spectrums to obtain the frequency domain total power.
5. The method of claim 1, wherein the calculating the sound level corresponding to the sound signal according to the total power in the frequency domain comprises:
and calculating the sound level corresponding to the sound signal according to the real value in the frequency domain total power.
6. A sound level meter, comprising: the digital domain unit is realized by an embedded CPU;
the analog domain unit includes: the gain adjusting module and the second-order Bessel high-pass filter;
the gain adjustment module is used for performing gain adjustment on the sound signal to obtain a gain signal;
the second-order Bessel high-pass filter is used for filtering the gain signal to obtain a filtered signal;
the digital domain unit includes: the analog-to-digital conversion module and the data processing module;
the analog-to-digital conversion module is used for performing analog-to-digital conversion on the filtering signal to obtain a sound digital signal;
the data processing module is used for calculating and processing the A frequency weighting coefficient of the sound digital signal to obtain a sound level corresponding to the sound signal;
wherein the data processing module comprises: the device comprises a conversion submodule, a correction submodule, a first calculation submodule and a second calculation submodule;
the conversion submodule is used for carrying out frequency domain conversion processing on the sound digital signal to obtain frequency domain data;
the correction submodule is used for correcting the A frequency weighting coefficient of the frequency domain data to obtain a frequency domain power spectrum;
the first calculating submodule is used for calculating the total power of the frequency domain according to the frequency domain power spectrum;
and the second calculating submodule is used for calculating the sound level corresponding to the sound signal according to the total power of the frequency domain.
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Citations (6)
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