Spatial low-frequency sound field reconstruction method and spatial low-frequency sound field reconstruction system

Abstract

The present invention discloses a spatial low-frequency sound field reconstruction method and a spatial low-frequency sound field reconstruction system. L The highest operating frequency of the high-frequency sound source is f H The amplitude value A of each sampling point is i (i=1,2,...,N), [Equation 35] JPEG2025500612000036.jpg12166T is the low frequency signal S L and a step S1 of selecting a plurality of high-frequency sound sources from an acoustic array composed of high-frequency sound sources and emitting high-frequency pulses to a target region, wherein the amplitude value of the high-frequency pulse emitted by the j-th high-frequency sound source is A j and the delay is [0036] JPEG2025500612000037.jpg14166, the target area being in a remote area of ​​the acoustic array; and step S2, superimposing high frequency pulses emitted by a selected high frequency sound source on the target area to generate a low frequency sound field S. L and step S3 of forming a transient low-frequency sound field in the space by superposing the transient sounds. This method forms a transient low-frequency sound field in the space by superposing the transient sounds, and has high acoustic energy conversion efficiency.

Description

Technical Field

[0001] The present invention belongs to the field of acoustic emission technology in acoustics, and specifically relates to a method and a system for reconstructing a low-frequency sound field using a high-frequency sound source.

Background Art

[0002] With the deepening of daily ocean exploration, the needs for underwater acoustic transducers have become widespread, and transducers for low-frequency emission are required to meet characteristics such as small size, light weight, and high efficiency.

[0003] Current low-frequency underwater acoustic transducers have drawbacks such as large size and weight, inconvenient installation, and difficulty in controlling the radiation angle. The parametric emission array is a solution in terms of the low-frequency sound field, but it has drawbacks such as low conversion efficiency at low frequencies and low sound field controllability.

Summary of the Invention

Means for Solving the Problems

[0004] An object of the present invention is to provide a spatial low-frequency sound field reconstruction method and a spatial low-frequency sound field reconstruction method that can form a transient low-frequency sound field in space with respect to the problems of the prior art.

[0005] The technical solution is as follows. In one aspect of the present invention, a method for reconstructing a spatial low-frequency sound field is disclosed, and the method includes: Sampling a low-frequency sound field S to be reconstructed at the maximum operating frequency f of a high-frequency sound source, and obtaining the amplitude value A (i = 1, 2,..., N) of each sampling point, which is step S1 where T is the time length of the low-frequency signal S, L at the maximum operating frequency f of a high-frequency sound source, H and obtaining the amplitude value A of each sampling point, i (i = 1, 2,..., N),

Equation

number

[0006] Furthermore, in step S2, when the number M of idle high-frequency sound sources in the acoustic array is less than N, select M idle high-frequency sound sources and emit high-frequency pulses into the target area, set the state of the M high-frequency sound sources to "occupied", and the amplitude value of the high-frequency pulse emitted by the j-th high-frequency sound source is A j and the delay is

number

[0007] Furthermore, in step S2, when the number M of idle high-frequency sound sources in the acoustic array is less than N, use M idle high-frequency sound sources to emit high-frequency pulses into the target area, specifically

number

Number

[0008] Preferably, the high-frequency pulse is a sinc signal with a cut-off frequency of f H where the high-frequency pulse is a sinc signal with a cut-off frequency of f

[0009] Preferably, it also includes an emission correction before the high-frequency sound source emits the high-frequency pulse. Specifically, providing a signal receiving device in the target area, the high-frequency sound source emitting an original high-frequency pulse in the target area, and the receiving device receiving the original high-frequency pulse in step S11; time-reversing the pulse signal received by the receiving device to obtain a corrected high-frequency emission signal in step S12; the high-frequency sound source using the corrected high-frequency pulse signal as the high-frequency pulse in step S13.

[0010] Preferably, the acoustic array composed of the high-frequency sound sources is a horizontal array.

[0011] Preferably, the space is underwater, and the horizontal array is located directly above the target area.

[0012] In another aspect, the present invention further discloses a spatial low-frequency sound field reconstruction system for realizing the above method. The spatial low-frequency sound field reconstruction system includes A high-frequency acoustic array 1, wherein the high-frequency acoustic array is composed of a plurality of high-frequency sound sources, and the high-frequency acoustic array 1 used to emit high-frequency pulses, A sampling module 2, wherein the sampling module 2 samples the low-frequency sound field S to be reconstructed L at the maximum operating frequency f of the high-frequency sound source H and obtains the amplitude value A of each sampling point i (i = 1, 2, …, N), and is used for [Number] where T is the time length of the low-frequency signal S L of the sampling module 2, A control module 3, wherein the control module 3 selects a plurality of idle high-frequency sound sources from the high-frequency acoustic array 1 and is used to emit high-frequency pulses to the target area. When the number of idle high-frequency sound sources in the acoustic array is N or more, then N idle high-frequency sound sources are selected from them and used to emit high-frequency pulses to the target area. The state of the selected high-frequency sound source to "occupied" set to , the amplitude value of the high-frequency pulse emitted by the i-th high-frequency sound source is A i and the delay is [Number] and the duration of the high-frequency pulse is N / f H . After the high-frequency pulse is emitted, the state of the corresponding high-frequency sound source is changed to "idle". The target area is in the remote area of the acoustic array. It includes the control module 3.

[0013] Furthermore, when the number M of idle high-frequency sound sources in the acoustic array is less than N, the control module 3 selects M idle high-frequency sound sources to emit high-frequency pulses to the target area, sets the states of the M high-frequency sound sources to "occupied", and the amplitude value of the high-frequency pulse emitted by the j-th high-frequency sound source is A j and the delay is [Number] and the duration of the high-frequency pulse is M / f H and the target area is in the remote area of the acoustic array. After the high-frequency pulse is emitted, the state of the corresponding high-frequency sound source is changed to "idle", where j = 1, 2,..., M.

[0014] Furthermore, when the number M of idle high-frequency sound sources in the acoustic array is less than N, the control module 3 emits high-frequency pulses to the target area using M idle high-frequency sound sources. Specifically, [Number] select one idle high-frequency sound source at each of the N time points of, and emit a high-frequency pulse s H with a duration of K / f i where the amplitude value of the high-frequency pulse s i is A i and the delay is [Number] where 10 < K < M, the high-frequency sound source is in the "occupied" state during the period of emitting the high-frequency pulse, and after the high-frequency pulse is emitted, this high-frequency sound source is changed to "idle". [Advantages of the Invention]

[0015] The method for reconstructing a spatial low-frequency sound field disclosed in the present invention has the following advantages. 1. It does not require a low-frequency sound source and directly forms a low-frequency sound field by superimposing high-frequency sound sources. 2. In this method, without using the non-linear effect of the sound field, a transient low-frequency sound field in space is formed by the method of superimposing transient sounds. The acoustic energy conversion efficiency is higher than that of a parametric emission array. [Brief Description of the Drawings]

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0017] Example 1 The present invention discloses a method for reconstructing a spatial low-frequency sound field. This example further explains the present invention by taking an underwater space as an example. As shown in FIG. 1, the specific steps are as follows. S1. Reconstruction target low-frequency sound field S L is sampled at the maximum operating frequency f H of the high-frequency sound source, and the amplitude value A i (i = 1, 2,..., N) of each sampling point is obtained.

Equation

[0018] In this example, the maximum operating frequency f H of the high-frequency sound source is 6 kHz, and the reconstruction target low-frequency sound field S L ​is a sine wave with a frequency of 235 Hz. Since the sine wave is a periodic wave, its time length T is set as the periodic duration, that is, T = 1 / 235, whereby N is calculated to be 26. After the reconstruction of the low-frequency sine wave of one period is completed, the idle high-frequency sound source is used to reconstruct the low-frequency sine wave of the next period.

[0019] S2. Ideally, when the number of high-frequency sound sources is N or more, N idle high-frequency sound sources are selected from the acoustic array composed of high-frequency sound sources, high-frequency pulses are emitted to the target area, the state of the selected high-frequency sound source is "occupied", the target area is in the remote area of the acoustic array, and the amplitude value of the high-frequency pulse emitted by the i-th high-frequency sound source is A i and the delay is

Number

Number

[0020] In actual applications, when the number of high-frequency sound sources in the acoustic array is less than N, or the number of idle high-frequency sound sources is less than N, high-frequency sound sources less than N are selected to reconstruct the low-frequency sound field. In this embodiment, the acoustic array has 21 high-frequency sound sources numbered 1-21. Each high-frequency sound source is independent of each other, has the same operating parameters, and the 21 high-frequency sound sources form a horizontal array. As shown in FIG. 2, the horizontal array is located directly above the target area. Here, 19 high-frequency sound sources are in the idle state, that is, 19 high-frequency sound fields are used to reconstruct the low-frequency sound field. In order to remove the distortion caused by the signal received by the receiving device, first, emission correction is performed on the high-frequency sound source. Specifically, the emission correction includes the following steps.

[0021] S11. A signal receiving device is provided in the target area, and the high-frequency sound source emits an original high-frequency pulse into the target area. This signal is a sinc signal with a cut-off frequency of f H as shown in FIG. 3(a). The receiving device receives the original high-frequency pulse, and due to distortion, the waveform of the signal received by the receiving device is shown in FIG. 3(b).

[0022] S12. The pulse signal received by the receiving device is time-reversed to obtain a corrected high-frequency emission signal, and the waveform of this signal is shown in FIG. 4(a).

[0023] S13. The high-frequency sound source uses the corrected high-frequency pulse signal as a high-frequency pulse. In this situation, the waveform of the signal received by the receiving device is shown in FIG. 4(b).

[0024] Through the above-described emission correction, the signal received by the receiving device in the target area becomes a sinc signal. The high-frequency pulses emitted by multiple high-frequency sound sources are superimposed on the target area as shown in FIG. 5.

[0025] S3. The high-frequency pulses emitted by the selected high-frequency sound sources are superimposed on the target area to form a low-frequency sound field S LForm it.

[0026] In this embodiment, the idle high-frequency sound sources numbered 2-20 are selected, the state of the selected high-frequency sound source is "occupied", and the corrected high-frequency emission signal is emitted from the central high-frequency sound source to both sides at a time interval of Δt = 1 / f H sequentially, and as shown in Fig. 6(a), these emission signals are superimposed on the target area in the far field to form a low-frequency sound field.

Number

Number

[0027] As shown in Fig. 8, the spatial low-frequency sound field reconstruction system for realizing the above method is a high-frequency acoustic array 1, where the high-frequency acoustic array is composed of a plurality of high-frequency sound sources, and the high-frequency acoustic array 1 used to emit high-frequency pulses, a sampling module 2, where the sampling module 2 samples the low-frequency sound field S L to be reconstructed at the maximum operating frequency f H of the high-frequency sound source, and is used to obtain the amplitude value A i (i = 1, 2,..., N) of each sampling point,

Number

Number

[0028] When the number M of idle high-frequency sound sources in the sound array is less than N, the control module 3 selects M idle high-frequency sound sources to emit high-frequency pulses to the target area, sets the states of the M high-frequency sound sources to "occupied", and the amplitude value of the high-frequency pulse emitted by the j-th high-frequency sound source is A j and the delay is

Number

[0029] Example 2 This example is the same as Example 1

Number

Number

Number

[0030] At the first M time points, that is,

Number

Number

Number

Claims

1. A method for reconstructing a spatial low-frequency sound field, comprising: Reconstruction target low-frequency sound field S Ｌ is sampled at the maximum operating frequency f Ｈ of the high-frequency sound source, and the amplitude value A ｉ (i = 1, 2,..., N) at each sampling point is obtained, which is a step of 【Number 25】 T is the time length of the low-frequency signal S Ｌ in step S1, and When the number of idle high-frequency sound sources in the acoustic array is N or more, selecting N idle high-frequency sound sources from them and emitting high-frequency pulses to the target area, setting the state of the selected high-frequency sound sources to "occupied", and the amplitude value of the high-frequency pulse emitted by the i-th high-frequency sound source is A ｉ and the delay is 【Number 26】 where the duration of the high-frequency pulse is N / f Ｈ where, after the high-frequency pulse is emitted, the state of the corresponding high-frequency sound source is changed to "idle", and the target region is in a remote region of the acoustic array in step S2, and Superposing a high-frequency pulse emitted by a selected high-frequency sound source on a target area to form a low-frequency sound field S Ｌ Step S3 of forming, and a method for reconstructing a spatial low-frequency sound field, characterized by including this.

2. In the step S2, when the number M of idle high-frequency sound sources in the acoustic array is less than N, M idle high-frequency sound sources are selected to emit high-frequency pulses to the target area, the states of the M high-frequency sound sources are set to "occupied", and the amplitude value of the high-frequency pulse emitted by the j-th high-frequency sound source is A ｊ and the delay is 【Number 27】 where the duration of the high-frequency pulse is M / f Ｈ wherein the target region is in the remote region of the acoustic array, and after the high-frequency pulse is emitted, the state of the corresponding high-frequency sound source is changed to "idle", and j = 1, 2,..., M. The method for reconstructing a spatial low-frequency sound field according to claim 1, characterized in that.

3. In the step S2, when the number M of idle high-frequency sound sources in the acoustic array is less than N, M idle high-frequency sound sources are used to emit high-frequency pulses into the target area. Specifically, 【Number 28】 Select one idle high-frequency sound source at each of the N time points, and the duration is K / f Ｈ to emit a high-frequency pulse s ｉ with the amplitude value of the high-frequency pulse s ｉ being A ｉ and the delay being 【Number 29】 where 10 < K < M, the high-frequency sound source is in an "occupied" state during the emission period of the high-frequency pulse, and after the high-frequency pulse is emitted, the state of this high-frequency sound source is changed to "idle". The method for reconstructing a spatial low-frequency sound field according to Claim 1.

4. Also included is the emission correction before the high-frequency sound source emits a high-frequency pulse. Specifically, the emission correction includes: providing a signal receiving device in the target area, and in step S11, the high-frequency sound source emits an original high-frequency pulse into the target area, and the receiving device receives the original high-frequency pulse; in step S12, the pulse signal received by the receiving device is time-reversed to obtain a corrected high-frequency emission signal; in step S13, the high-frequency sound source uses the corrected high-frequency pulse signal as a high-frequency pulse. The method for reconstructing a spatial low-frequency sound field according to Claim 1.

5. The acoustic array composed of the high-frequency sound sources is a horizontal array. The method for reconstructing a spatial low-frequency sound field according to Claim 1.

6. The space is underwater, and the horizontal array is located directly above the target area. The method for reconstructing a spatial low-frequency sound field according to Claim 5.

7. A spatial low-frequency sound field reconstruction system, comprising: a high-frequency acoustic array (1) composed of a plurality of high-frequency sound sources and used to emit high-frequency pulses; Reconstruction target low-frequency sound field S Ｌ is sampled at the maximum operating frequency f Ｈ of the high-frequency sound source, and the amplitude value A ｉ (i = 1, 2,..., N) at each sampling point is obtained and used, 【30 numbers】 T is the time length of the low-frequency signal S Ｌ and a sampling module (2), A control module (3) that selects a plurality of idle high-frequency sound sources from a high-frequency sound array (1), emits high-frequency pulses to a target area, and when the number of idle high-frequency sound sources in the sound array is N or more, then selects N idle high-frequency sound sources and emits high-frequency pulses to the target area, which sets the state of the selected high-frequency sound source to "occupied", and the amplitude value of the high-frequency pulse emitted by the i-th high-frequency sound source is A ｉ and the delay is 【Number 31】 where the duration of the high-frequency pulse is N / f Ｈ wherein after the high-frequency pulse is emitted, the state of the corresponding high-frequency sound source is changed to "idle", and the target area is in the remote area of the acoustic array, and a control module (3), and a spatial low-frequency sound field reconstruction system characterized by comprising the same.

8. When the number M of idle high-frequency sound sources in the acoustic array is less than N, the control module (3) selects M idle high-frequency sound sources, emits high-frequency pulses to the target area, sets the states of the M high-frequency sound sources to "occupied", and the amplitude value of the high-frequency pulse emitted by the j-th high-frequency sound source is A ｊ and the delay is 【Number 32】 where the duration of the high-frequency pulse is M / f Ｈ where the target area is in the remote area of the acoustic array, and after the high-frequency pulse is emitted, the state of the corresponding high-frequency sound source is changed to "idle", and j = 1, 2,..., M. The spatial low-frequency sound field reconstruction system according to claim 7

9. When the number M of idle high-frequency sound sources in the acoustic array is less than N, the control module (3) selects M idle high-frequency sound sources to emit high-frequency pulses into the target area. Specifically, 【Number 33】 Select one idle high-frequency sound source at each of the N time points, and emit a high-frequency pulse s Ｈ with a duration of K / f ｉ such that the amplitude value of the high-frequency pulse s ｉ is A ｉ and the delay is 【Number 34】 where 10 < K < M, the high-frequency sound source is in an "occupied" state during the period of emitting the high-frequency pulse, and after the high-frequency pulse is emitted, the state of this high-frequency sound source is changed to "idle". The spatial low-frequency sound field reconstruction system according to Claim 7.

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