A charging pile noise reduction method, device and system

Abstract

The present application relates to the field of noise reduction technology, and discloses a charging pile noise reduction method, device and system, comprising the following steps: setting a plurality of groups of noise source collection points, and obtaining mixed noise at each group of noise source collection points; separating each group of mixed noise into a plurality of groups of original single noises; obtaining a corresponding playback delay time of each group of original single noises, and generating mixed noise reduction noise based on the playback delay time; and simultaneously playing the mixed noise reduction noise when the charging pile is running, thereby breaking through the bottleneck that mixed noise sources cannot achieve effective noise reduction, and having the advantage of low noise reduction cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of noise reduction technology, in particular to a charging pile noise reduction method, device and system. BACKGROUND

[0002] In the working process of the existing charging pile, due to the need for heat dissipation, there is often a lot of noise. At present, passive means such as noise reduction cotton and diversion of air outlet are often used. The existing charging column active noise reduction uses water cooling and air conditioner outdoor unit to assist in noise reduction.

[0003] However, the noise reduction cotton reduces the air circulation efficiency and affects heat dissipation. The diversion of the air outlet has a large negative impact on the overall size, is not easy to maintain and has high cost. All passive noise reduction methods have limited noise reduction effect, and single use cannot achieve the purpose of significantly reducing operating noise. The existing active noise reduction methods, such as water cooling and air conditioner outdoor unit, have the following disadvantages: high cost and high cost burden. For single noise source noise reduction, although the cost is low, the noise reduction is not obvious for non-diffusion direction, and the noise reduction effect is poor for multiple noise sources. SUMMARY

[0004] The present application provides a charging pile noise reduction method, device and system, which has the advantages of low noise reduction cost and breaks through the bottleneck of mixed noise source that cannot be effectively reduced.

[0005] In order to solve the above technical problems, the present application solves the problems by the following technical solutions:

[0006] A charging pile noise reduction method, comprising the following steps:

[0007] A plurality of groups of noise source collection points are set, and mixed noise at each group of noise source collection points is obtained;

[0008] Each group of mixed noise is separated into a plurality of groups of original single noise;

[0009] The playback delay time corresponding to each group of original single noise is obtained, and mixed noise reduction noise is generated based on the playback delay time;

[0010] When the charging pile is running, the mixed noise reduction noise is played at the same time.

[0011] Optionally, each group of mixed noise is separated into a plurality of groups of original single noise, comprising the following steps:

[0012] The adjacent two groups of mixed noise are compared to obtain intermediate differential noise, and the adjacent intermediate differential noise is continuously compared until the original single noise is obtained.

[0013] Optionally, the playback delay time corresponding to each group of original single noise is obtained, comprising the following steps:

[0014] Set a test delay time, each group of the original single noise is based on the test delay time, and continuous delay is performed to obtain a plurality of groups of delay noise sound waves;

[0015] Obtain a first wave peak and a first wave trough of each group of the delay noise sound wave, and obtain a second wave peak and a second wave trough of the original single noise corresponding to the delay noise sound wave;

[0016] Obtain a test delay time sum when the first wave peak and the second wave trough or the first wave trough and the second wave peak coincide, and determine that the test delay time sum is a playing delay time.

[0017] Optionally, determining that the first wave peak and the second wave trough or the first wave trough and the second wave peak coincide includes the following steps:

[0018] Obtain a first wave peak time position of the first wave peak and a first wave trough time position of the second wave trough;

[0019] If the first wave peak time position and the first wave trough time position are the same, the first wave peak and the second wave trough coincide, otherwise, they do not coincide;

[0020] Obtain a second wave trough time position of the first wave trough and a second wave peak time position of the second wave peak;

[0021] If the second wave trough time position and the second wave peak time position are the same, the first wave trough and the second wave peak coincide, otherwise, they do not coincide.

[0022] A charging pile noise reduction device, the charging pile noise reduction device performs the charging pile noise reduction method as described in any one of the above, comprising a noise collection component, a processor and a playing component;

[0023] The noise collection component is used to obtain mixed noise at each group of noise source collection points;

[0024] The processor is used to separate each group of the mixed noise into a plurality of groups of original single noises, and obtain a playing delay time corresponding to each group of the original single noises, and generate mixed noise reduction noise based on the playing delay time;

[0025] The playing component is used to play the mixed noise reduction noise when the charging pile is running.

[0026] Optionally, the noise collection component is installed at a noise source of the charging pile.

[0027] A charging pile noise reduction system, comprising a noise collection unit, a differential separation unit, a delay processing unit and a playing unit;

[0028] The noise collection unit is configured to set a plurality of groups of noise source collection points and acquire mixed noise at each group of the noise source collection points.

[0029] The difference separation unit is configured to separate each group of the mixed noise into a plurality of groups of original single noise.

[0030] The delay processing unit is configured to acquire a playing delay time corresponding to each group of the original single noise and generate mixed noise reduction noise based on the playing delay time.

[0031] The playing unit is configured to play the mixed noise reduction noise while the charging pile is operating.

[0032] Optionally, the difference separation unit comprises a comparison unit.

[0033] The comparison unit is configured to compare adjacent two groups of the mixed noise to obtain intermediate difference noise and continue comparison of adjacent intermediate difference noise until original single noise is acquired.

[0034] Optionally, the delay processing unit comprises a continuous delay unit, a peak-valley acquisition unit and a delay time determination unit.

[0035] The continuous delay unit is configured to set a test delay time, and each group of the original single noise is subjected to continuous delay based on the test delay time to obtain a plurality of groups of delay noise sound waves.

[0036] The peak-valley acquisition unit is configured to acquire a first peak and a first valley of each group of the delay noise sound wave and acquire a second peak and a second valley of the original single noise corresponding to the delay noise sound wave.

[0037] The delay time determination unit is configured to acquire a test delay time sum when the first peak coincides with the second peak or the first valley coincides with the second valley and determine the test delay time sum as the playing delay time.

[0038] Optionally, the delay time determination unit comprises a first coincidence determination unit and a second coincidence determination unit.

[0039] The first coincidence determination unit is configured to acquire a first peak time position of the first peak and a first valley time position of the second valley, and if the first peak time position is same as the first valley time position, the first peak coincides with the second valley, otherwise, the first peak does not coincide with the second valley.

[0040] The second coincidence determination unit is configured to acquire a second valley time position of the first valley and a second peak time position of the second peak, and if the second valley time position is same as the second peak time position, the first valley coincides with the second peak, otherwise, the first valley does not coincide with the second peak.

[0041] Compared with the prior art, the technical scheme provided by the present application has the following beneficial effects:

[0042] In the charging pile environment with multiple mixed noises, the collected mixed noises can be separated into original single noises, and the original single noises are processed by time delay, so that the mixed noise reduction noises processed by time delay are used to balance the mixed noises, thereby achieving the active noise reduction effect, and without changing the original structure of the charging pile, the method has higher applicability. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0044] Figure 1 The noise source collection point in the charging pile noise reduction method proposed in this embodiment, the matrix layout of the noise source and the sound transmission direction;

[0045] Figure 2 The sound wave superposition diagram when the mixed noise and the mixed noise reduction noise are played at the same time in the ideal state proposed in this embodiment. DETAILED DESCRIPTION

[0046] The present application will be further described in detail below in combination with the embodiments, and the following embodiments are an explanation of the present application and the present application is not limited to the following embodiments.

[0047] Embodiment one

[0048] As shown in Figure 1 , a charging pile noise reduction method comprises the following steps: setting a plurality of noise source collection points, and acquiring mixed noise at each noise source collection point; the present embodiment mainly solves the noise generated by the cooling fan of the charging pile; the cooling fan of the charging pile is provided with a plurality of cooling fans, and the cooling fans are arranged in a matrix; for example, the number of cooling fans arranged in an array is nine; at this time, the noise generated by each cooling fan interferes with each other, so the present embodiment first needs to set a plurality of noise source collection points; in Figure 1 , nine noise sources are sequentially marked as A-I; at this time, the first noise source collection point is set at the center position of the noise source A, the noise source B, the noise source D and the noise source E; based on the same center division principle, the positions of the noise source collection point 2, the noise source collection point 3 and the noise source collection point 4 are set, and the mixed noise at each collection point is acquired.

[0049] Further, the mixed noise of each group is separated into several groups of original single noise, including the following steps: comparing the adjacent two groups of mixed noise to obtain intermediate differential noise, and continuing to compare the adjacent intermediate differential noise until the original single noise is obtained.

[0050] Specifically, since the arrival time of different waveforms is different at the same time, the waveforms reaching the same distance at the same time are consistent, so the difference operation can be performed. The mixed noise of the noise source collection point 1 can be approximately generated by mixing noise sources A, B, D and E; the mixed noise of the noise source collection point 2 can be approximately generated by mixing noise sources B, C, E and F; and the mixed noise of the noise source collection point 3 can be approximately generated by mixing noise sources D, E, G and H. Therefore, by comparing the mixed noise of the noise source collection point 1 with the mixed noise of the noise source collection point 2, the mixed wave BE generated by mixing noise sources B and E can be obtained. At this time, by comparing the mixed noise of the noise source collection point 1 with the mixed noise of the noise source collection point 3, the mixed wave DE generated by mixing noise sources D and E can be obtained. Then, by comparing the mixed wave BE with the mixed wave DE, the E wave with the same waveform can be obtained. Based on the E wave, the A wave, the B wave and the D wave can be obtained. Based on the same difference operation method, the waveform of each noise source, i.e. all original single noises, can be obtained. In this embodiment, the intermediate differential noise refers to the mixed wave noise obtained after each comparison.

[0051] Further, the playback delay time corresponding to each group of original single noise is obtained, and the mixed noise reduction noise is generated based on the playback delay time. The playback delay time corresponding to each group of original single noise is obtained, including the following steps: setting a test delay time, and continuously delaying each group of original single noise based on the test delay time to obtain several groups of delay noise sound waves.

[0052] After the waveform of each noise source is obtained, delay processing is needed, and since the waveform of each noise source is different, the corresponding delay time needs to be simulated. Since the main sound wave frequency of the charging pile cooling fan is 0.5KHZ~1KHZ, and the program can sample and design 0.35KHZ~10KHZ sound wave form when designing delay, the maximum delay time depends on the frequency of the smallest sound wave: the period of 0.35KHZ sound wave is 3ms, and the maximum delay comparison is half a period 1.5ms. The maximum delay comparison is finally determined to be 1.5ms delay, and the single delay time depends on the frequency of the largest sound wave 10KHZ, and the noise single period is 0.1ms. The delay is 1 / 10 of the period as the delay unit, and 0.01ms is determined as the single delay time, that is, the test delay time can be 0.01ms. After each delay, a time interval of delay noise sound wave is collected, which can be 0.05ms, and the delay and delay noise sound wave extraction are repeated until the maximum sound wave period sampling of 1.5ms is completed, and then the extracted delay noise sound wave is compared.

[0053] Specifically, the first peak and the first valley of each group of delay noise sound wave are obtained, and the second peak and the second valley of the original single noise corresponding to the delay noise sound wave are obtained; the test delay time sum when the first peak and the second valley or the first valley and the second peak coincide is obtained, and the test delay time sum is determined as the playing delay time, wherein determining that the first peak and the second valley or the first valley and the second peak coincide comprises the following steps: obtaining the first peak time position of the first peak and the first valley time position of the second valley; if the first peak time position and the first valley time position are the same, the first peak and the second valley coincide, otherwise, they do not coincide; obtaining the second valley time position of the first valley and the second peak time position of the second peak; if the second valley time position and the second peak time position are the same, the first valley and the second peak coincide, otherwise, they do not coincide.

[0054] Further, as shown in Figure 2 , the waveform of each noise source is delayed by the playing delay time obtained by the above method to obtain the delayed single noise, and all the single noises are summarized as mixed noise reduction noise. Specifically, taking noise source collection point 1 as an example, the mixed noise reduction noise can be expressed as f(X1)=θ A *f(A)*T A +θ B *f(B)*T B +θ D *f(D)*T D +θ E *f(E)*T E; wherein θ represents the noise interference weight, for the noise source collection point 1, the sound source signals of the noise source A, the noise source B, the noise source D and the noise source E can be abstractly taken as the main, the rest of the noise sources are secondary in sampling, and the interference can be abstractly ignored, the interference weight is obtained through the distance relationship between the noise source collection point and the noise source, specifically, the distance produces a sound wave attenuation period and a phase two coefficients superposition, wherein the phase is calculated by frequency to obtain half wave period, and then the distance is calculated; T represents the delay playback time; f(A) represents the sound wave signal of the noise source A, and similarly, f(B), f(D), f(E) represent the sound waves of the corresponding noise sources.

[0055] When the charging pile is running, the mixed noise reduction noise is played at the same time, at this time, the wave crest and the wave trough of the mixed noise emitted by the charging pile and the mixed noise reduction noise are balanced, the noise decibel is reduced, and in an ideal state, the original sound wave of the mixed noise and the simulated sound wave after the delay processing are superimposed and will be completely cancelled out. Because the noise source is irregular, adding a delay to the original sound source can make part of the wave crest and the wave trough overlap, thereby producing a noise reduction effect.

[0056] Embodiment two

[0057] A charging pile noise reduction device, the charging pile noise reduction device performs the charging pile noise reduction method as in embodiment one, comprising a noise collection component, a processor and a playback component; wherein the noise collection component is provided with a plurality of noise collectors, the noise collection component is installed at the noise source of the charging pile, the noise collector can be a sound sensor, which is used to obtain the mixed noise at each group of noise source collection points; the processor is used to separate each group of mixed noise into a plurality of groups of original single noise, and obtain the playback delay time corresponding to each group of original single noise, and generate a mixed noise reduction noise based on the playback delay time; the playback component is used to play the mixed noise reduction noise at the same time when the charging pile is running, the playback component can be a loudspeaker, and can be arranged in an array on the charging pile.

[0058] Embodiment three

[0059] A charging pile noise reduction system, comprising a noise collection unit, a difference separation unit, a delay processing unit and a playback unit; the noise collection unit is used to set a plurality of groups of noise source collection points and obtain the mixed noise at each group of noise source collection points; the embodiment mainly solves the noise generated by the cooling fan of the charging pile, the cooling fan of the charging pile is provided with a plurality of groups, and is arranged in a matrix, and the number of the cooling fan is taken as an example, which is nine arranged in an array, at this time, the noise generated by each cooling fan exists mutual interference, therefore, the embodiment first needs to set a plurality of noise source collection points, in Figure 1In the embodiment, nine noise sources are sequentially marked as A-I, at this time, the first noise source collection point is set at the center position of the noise source A, the noise source B, the noise source D and the noise source E, the positions of the noise source collection point 2, the noise source collection point 3 and the noise source collection point 4 are set based on the same center division principle, and the mixed noise located at each collection point is obtained.

[0060] Further, the difference separation unit is used to separate each group of mixed noise into several groups of original single noise, and specifically, the difference separation unit includes a comparison unit; the comparison unit is used to compare the adjacent two groups of mixed noise to obtain intermediate difference noise, and the comparison of the adjacent intermediate difference noise is continuously performed until the original single noise is obtained.

[0061] Specifically, since different waveforms arrive at different times at the same time, the waveforms arriving at the same distance at the same time are consistent, so the difference operation can be performed, first, the mixed noise of the noise source collection point 1 can be approximately generated by the noise sources A, B, D and E; the mixed noise of the noise source collection point 2 can be approximately generated by the noise sources B, C, E and F, and the mixed noise of the noise source collection point 3 can be approximately generated by the noise sources D, E, G and H, therefore, the mixed wave BE generated by the noise sources B and E with the same waveform can be obtained by comparing the mixed noise of the noise source collection point 1 with the mixed noise of the noise source collection point 2, at this time, the mixed wave DE generated by the noise sources D and E with the same waveform can be obtained by comparing the mixed noise of the noise source collection point 1 with the mixed noise of the noise source collection point 3, and the mixed wave BE and the mixed wave DE are compared to obtain the E wave with the same waveform, and the A wave, the B wave and the D wave are obtained based on the E wave, and based on the same difference operation method, the waveform of each noise source can be obtained, that is, all the original single noise, wherein the intermediate difference noise in the embodiment refers to the mixed wave noise obtained after each comparison.

[0062] Further, the delay processing unit is used to obtain the playing delay time corresponding to each group of original single noise, and generate mixed noise reduction noise based on the playing delay time, wherein the delay processing unit includes a continuous delay unit, a peak-valley obtaining unit and a delay time determining unit; the continuous delay unit is used to set a test delay time, and each group of original single noise is subjected to continuous delay based on the test delay time to obtain several groups of delay noise sound waves.

[0063] After the waveform of each noise source is obtained, delay processing is needed, and since the waveform of each noise source is different, the corresponding delay time needs to be simulated. Since the main sound wave frequency of the charging pile cooling fan is 0.5KHZ~1KHZ, and the program can sample and design 0.35KHZ~10KHZ sound wave form when designing delay, the maximum delay time depends on the frequency of the smallest sound wave: the period of 0.35KHZ sound wave is 3ms, and the maximum delay comparison is half a period, 1.5ms. Finally, the maximum delay comparison is determined to be 1.5ms delay, and the single delay time depends on the frequency of the largest sound wave 10KHZ, and the noise single period is 0.1ms. The delay is 1 / 10 of the period as the delay unit, and 0.01ms is determined as the single delay time, that is, the test delay time can be 0.01ms. After each delay, a time interval of delay noise sound wave is collected, which can be 0.05ms, and the delay and delay noise sound wave extraction are repeated until the maximum sound wave period sampling of 1.5ms is completed, and then the extracted delay noise sound wave is compared.

[0064] Specifically, the peak valley acquisition unit is configured to acquire a first wave peak and a first wave valley of each group of delay noise sound waves, and acquire a second wave peak and a second wave valley of a corresponding original single noise of the delay noise sound wave; the delay time determination unit is configured to acquire a test delay time sum when the first wave peak and the second wave valley or the first wave valley and the second wave peak coincide, and determine the test delay time sum as a playing delay time, wherein the delay time determination unit comprises a first coincidence determination unit and a second coincidence determination unit; the first coincidence determination unit is configured to acquire a first wave peak time position of the first wave peak and a first wave valley time position of the second wave valley; if the first wave peak time position is same as the first wave valley time position, the first wave peak and the second wave valley coincide, otherwise, they do not coincide; the second coincidence determination unit is configured to acquire a second wave valley time position of the first wave valley and a second wave peak time position of the second wave peak; if the second wave valley time position is same as the second wave peak time position, the first wave valley and the second wave peak coincide, otherwise, they do not coincide.

[0065] Further, the waveform of each noise source is delayed according to the playing delay time obtained by the above method to obtain the delayed single noise, and all the single noises are summarized as mixed noise reduction noise. Specifically, taking noise source collection point 1 as an example, the summarized mixed noise reduction noise can be expressed as f(x1)=θ A *f(A)*T A +θ B *f(B)*T B +θ D *f(D)*T D +θ E *f(E)*T E; wherein, θ represents noise interference weight, for noise source collection point 1, noise source A, noise source B, noise source D and noise source E can be abstractly sound source signal, the rest of the noise source is secondary in sampling, and the interference can be ignored, the interference weight is obtained by the distance relationship between the noise source collection point and the noise source, specifically, the distance will produce a sound wave attenuation period and phase two coefficients superposition, wherein the phase is calculated by frequency half wave period, and then the distance is calculated; T represents the delay playback time; f(A) represents the sound wave signal of noise source A, similarly, f(B), f(D), f(E) represent the sound wave of the corresponding noise source.

[0066] When the charging pile is running, the mixed noise and the mixed noise reduction noise are played at the same time, at this time, the wave crest and the wave trough of the mixed noise and the mixed noise reduction noise emitted by the charging pile are balanced, the noise decibel is reduced, and in an ideal state, the original sound wave and the simulated sound wave after delay processing of the mixed noise are superimposed and will be completely cancelled out. Because the noise source is irregular, adding delay to the original sound source can make part of the wave crest and the wave trough overlap, thereby producing a noise reduction effect.

[0067] The units or modules described in the embodiments of the present application can be implemented in software or hardware. The described units or modules can also be arranged in a processor, for example, each of the units can be a software program arranged in a computer or a mobile smart device, or a separately configured hardware device. In some cases, the names of these units or modules do not constitute a limitation on the units or modules themselves.

[0068] The above description is only the preferred embodiments of the present application and the explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, and also covers other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the concept of the present application. For example, the above features are replaced with the technical features disclosed in the present application (but not limited to) having similar functions to form technical solutions.

Claims

1. A method for reducing noise of a charging pile, characterized in that, The method comprises the following steps: a plurality of noise source collection points are set, and mixed noise at each of the noise source collection points is obtained; each of the mixed noise is separated into a plurality of original single noises, specifically, adjacent two groups of the mixed noise are compared to obtain intermediate differential noise, and adjacent comparison of the intermediate differential noise is continuously performed until the original single noise is obtained; a playing delay time corresponding to each of the original single noises is obtained, and mixed noise reduction noise is generated based on the playing delay time, wherein the playing delay time corresponding to each of the original single noises is obtained by the following steps: a test delay time is set, each of the original single noises is continuously delayed based on the test delay time to obtain a plurality of delay noise sound waves; a first wave peak and a first wave trough of each of the delay noise sound waves are obtained, and a second wave peak and a second wave trough of the original single noise corresponding to the delay noise sound wave are obtained; a test delay time sum when the first wave peak and the second wave trough or the first wave trough and the second wave peak coincide is obtained, and the test delay time sum is determined as the playing delay time; the mixed noise reduction noise is played simultaneously when the charging pile is running.

2. The charging pile noise reduction method of claim 1, wherein, The determination of the coincidence of the first wave peak and the second wave trough or the first wave trough and the second wave peak comprises the following steps: a first wave peak time position of the first wave peak and a first wave trough time position of the second wave trough are obtained; if the first wave peak time position is the same as the first wave trough time position, the first wave peak and the second wave trough coincide, otherwise, they do not coincide; a second wave trough time position of the first wave trough and a second wave peak time position of the second wave peak are obtained; if the second wave trough time position is the same as the second wave peak time position, the first wave trough and the second wave peak coincide, otherwise, they do not coincide.

3. A charging pile noise reduction device, characterized in that, The charging pile noise reduction device executes the charging pile noise reduction method according to any one of claims 1-2, comprising a noise collection component, a processor and a playing component; the noise collection component is used to obtain mixed noise at each of the noise source collection points; the processor is used to separate each of the mixed noise into a plurality of original single noises, and obtain a playing delay time corresponding to each of the original single noises, and generate mixed noise reduction noise based on the playing delay time; the playing component is used to play the mixed noise reduction noise simultaneously when the charging pile is running.

4. The charging pile noise reduction device according to claim 3, characterized in that, The noise collection component is installed at a noise source of the charging pile.

5. A charging pile noise reduction system, characterized in that, It comprises a noise collection unit, a differential separation unit, a delay processing unit and a playing unit; the noise collection unit is used to set a plurality of noise source collection points, and obtain mixed noise at each of the noise source collection points; the differential separation unit is used to separate each of the mixed noise into a plurality of original single noises, and the differential separation unit comprises a comparison unit, which is used to compare adjacent two groups of the mixed noise to obtain intermediate differential noise, and continuously compare adjacent intermediate differential noise until the original single noise is obtained; the noise collection unit is used to set a plurality of noise source collection points, and obtain mixed noise at each of the noise source collection points; The delay processing unit is configured to obtain a playing delay time corresponding to each group of the original single noise, and generate mixed noise based on the playing delay time, wherein the delay processing unit comprises a continuous delay unit, a peak-valley obtaining unit and a delay time determining unit, the continuous delay unit is configured to set a test delay time, and each group of the original single noise is continuously delayed based on the test delay time to obtain a plurality of groups of delayed noise sound waves; the peak-valley obtaining unit is configured to obtain a first peak and a first valley of each group of the delayed noise sound waves, and obtain a second peak and a second valley of the original single noise corresponding to the delayed noise sound waves; and the delay time determining unit is configured to obtain a test delay time sum when the first peak and the second valley or the first valley and the second peak coincide, and determine that the test delay time sum is the playing delay time. The playing unit is configured to play the mixed noise when the charging pile is in operation.

6. The charging pile noise reduction system according to claim 5, characterized in that, The delay time determining unit comprises a first coincidence determining unit and a second coincidence determining unit. The first coincidence determining unit is configured to obtain a first peak time position of the first peak and a first valley time position of the second valley, and if the first peak time position is the same as the first valley time position, the first peak coincides with the second valley, otherwise, the first peak does not coincide with the second valley. The second coincidence determining unit is configured to obtain a second valley time position of the first valley and a second peak time position of the second peak, and if the second valley time position is the same as the second peak time position, the first valley coincides with the second peak, otherwise, the first valley does not coincide with the second peak.

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