JP2003307565A - Acoustic target - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a downsized and costless acoustic target. <P>SOLUTION: Of this acoustic target 1, a wave receiver 10 and a wave transmitter 20 are disposed close to each other and connected respectively by conductive cables 11 and 21 to a signal converter 30 in a control box 100. The converter includes a wave reception-transmission duplication preventing circuit 40, a target strength setting circuit 50, a delay time setting circuit 60, a Doppler shift setting circuit 70, and a pulse extension circuit 80. The preventing circuit makes the transmitter inoperative while the receiver is in operation and makes the receiver inoperative while the transmitter is in operation. Although the receiver and the transmitter are disposed close to each other, acoustic feedback does not occur. Since no analysis processing is performed in the strength setting circuit, the time setting circuit, the shift setting circuit, or the extension circuit, electric power is less consumed and therefore a battery 110 can be made smaller. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to acoustic targets for sonar performance evaluation testing and operational training.

[0002]

BACKGROUND OF THE INVENTION Ships, especially military ships, are often equipped with sonar. When developing a sonar, it is necessary to evaluate the performance that the sonar requires, that is, whether the sonar can reliably capture the target situation. Therefore, a large number of man-hours will be required if a large-scale test is carried out at sea with a target ship and the like many times.

Further, when a sonar is attached to a ship, the operator must be trained to become familiar with the operation of the sonar. For this training, a large number of large-scale operations at sea with the target ship etc. are required. Performing such tests requires a great deal of man-hours. Therefore, an acoustic target has been developed that produces a reflected sound similar to the actual target when the sonar is activated, so that a large-scale test at sea is not required.

By the way, an acoustic target receives a sound wave and converts it into an input electric signal, and an output electric signal which can be converted into a desired output sound wave based on the input electric signal received by the wave receiver. It has a signal conversion device which generates, and a wave transmitter which converts an electric signal from the signal conversion device into a sound wave and transmits an output sound wave. Here, since the wave receiver is a microphone and the wave transmitter is a speaker, howling occurs when they are arranged close to each other. Therefore, in a conventional acoustic target, the distance between the wave receiver and the wave transmitter may be increased, or,
The receiver and transmitter are designed to have directivity so that they do not overlap.

In the conventional acoustic target, the received signal is A
A / D conversion is performed, a DSP (digital signal processor) performs high-speed arithmetic processing using an FFT (fast Fourier transformer) or the like to generate a transmission signal, which is D / A converted and transmitted. . Therefore, the battery consumes a large amount of power and requires a large capacity, and as a result, the entire device becomes large and heavy, and the cost is high.

[0006]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a small acoustic target that is inexpensive.

[0007]

According to the first aspect of the present invention, there is provided an acoustic target, which receives an input sound wave transmitted by a sonar and converts the acoustic wave into an electric input signal, and a receiver. Signal converter that converts the electrical input signal of the device into an electrical output signal that can be converted into a desired output sound wave, and a transmitter that converts the electrical output signal from the signal converter into a sound wave and outputs the output sound wave. A wave receiver and a power supply means for supplying electric power for driving the signal converter, the wave receiver, and the wave transmitter to prevent the signal converter from overlapping the operating time of the wave receiver and the wave transmitter. There is provided an acoustic target including a wave transmission duplication preventing means, wherein a wave receiver and a wave transmitter are arranged in close proximity to each other.
In the acoustic target configured as described above, the operation time of the wave receiver and the wave transmitter is prevented from overlapping by the wave reception / duplication preventing means, and therefore howling may not occur even if they are arranged close to each other.

According to the second aspect of the present invention, the acoustic target is a receiver that receives the input sound wave transmitted by the sonar and converts it into an electrical input signal, and an electrical input signal from the receiver. Signal conversion device for converting an electrical output signal that can be converted into a desired output sound wave, a wave transmitter for converting an electrical output signal from the signal conversion device into a sound wave and transmitting the output sound wave, and a signal conversion device An acoustic target including a power supply unit for supplying power to drive the device, the wave receiver, and the wave transmitter, and the signal conversion device including an unanalyzed wave-making circuit that does not include analysis processing of an input signal Provided. The acoustic target configured in this way has low power consumption of the signal conversion device.

According to the invention of claim 3, in the invention of claim 1 or 2, the signal conversion device includes a target strength setting circuit capable of adjusting the target strength which is the strength of the output sound wave with respect to the input sound wave. An acoustic target is provided.

According to the invention of claim 4, in the invention of claim 1 or 2, the signal conversion device includes an acoustic wave including a delay time setting circuit capable of adjusting the transmission time of the output sound wave with respect to the reception time of the input sound wave. Target is provided.

According to the invention of claim 5, in the invention of claim 1 or 2, the signal conversion device includes an acoustic target including a Doppler shift setting circuit capable of changing the frequency of the output sound wave with respect to the frequency of the input sound wave. Provided.

According to the invention of claim 6, in the invention of claim 1 or 2, the signal conversion device includes an acoustic wave including a pulse expansion circuit capable of changing the pulse width and the pulse length of the output sound wave with respect to the input sound wave. Target is provided.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a view for explaining an acoustic target of the present invention, in which the acoustic target 1 receives a sound wave emitted by a sonar 2 mounted on a ship 3 (so that the sonar 2 is an active sonar). , Which generates and transmits a sound wave to be transmitted toward the sonar 2 on the basis of the received sound wave, and is mainly applied to the wave receiver 10 and the wave transmitter 20 positioned in the sea and the seabed. The control box 100 is installed.

The wave receiver 10 and the wave transmitter 20 are arranged close to each other, and the conductive cables 11 and 2 are provided, respectively.
1 is connected to the signal conversion device 30 in the control box 100, but the conductive cables 11 and 21 are bundled together. Further, the wire 210 extending upward is connected to the float 200 floating above the sea surface to prevent the grounding place from becoming unknown.

In the control box 100, a battery 110 is provided in addition to the signal converter 30, and the signal converter 3 is supplied by the power supplied from the battery 110.
0 and the wave receiver 10 connected to the signal conversion device 30
And the transmitter 20 is driven. FIG. 2 is a diagram showing a configuration of the signal conversion device 30, which includes a transmission / reception wave duplication prevention circuit 40, a target strength setting circuit 50, a delay time setting circuit 60, a Doppler shift setting circuit 70, It includes a pulse stretching circuit 80.

Each circuit will be described below. at first,
The transmitted / received wave duplication prevention circuit 40 will be described. Although a circuit diagram is not particularly shown, as described above, since the receiver 10 is a microphone and the transmitter 20 is a speaker as described above, howling occurs when the two are used in close proximity to each other, as is well known. . Therefore, in order to prevent this howling, the wave transmitter 20 is masked to make it inoperative while the wave receiver 10 is operating, and conversely, while the wave receiver 20 is operating.
A mask is applied to the deactivation.

FIG. 3 is a diagram for explaining the operation of the received / transmitted wave duplication prevention circuit 40 having the above-described structure. By doing so, howling does not occur, so that the receiver 10 and the receiver 10 are transmitted. Since the wave receivers 20 can be arranged close to each other and it is not necessary to have a structure having directivity, the wave receiver 1
0 and the wave transmitter 20 can be housed compactly, and the device can be made simple and small.

Next, the target strength setting circuit 5
0 will be described. The target strength is the strength of the output sound wave with respect to the input sound wave, and represents the strength of the reflection sound.When the target is large or hard, the target strength is large, and when the target is small or soft, the target strength is large. Becomes smaller. Therefore, by changing this, it is possible to represent a case where a large or small target, a hard or small target is captured.

FIG. 4 is a diagram showing an example of the target strength setting circuit 10, which is a voltage control amplifier 51.
And a gain control voltage obtained by converting a TS (target strength) setting digital signal into an analog voltage by the D / A converter 52 is applied to adjust the gain of the output signal with respect to the input signal.

FIG. 5A shows the operation when the target strength setting of the target strength setting circuit 50 is increased, and FIG. 5B shows the target strength.
The operation when the setting of the target strength of the strength setting circuit 10 is increased is shown. In the upper part of the voltage control amplifier, the output wave is larger than the input wave, the middle part is the output wave is equal to the input wave, and the lower part is the output wave is smaller than the input wave. Shown respectively.

Next, the delay time setting circuit 60 will be described. This is to adjust the delay time from the reception of the input sound wave to the transmission of the output sound wave. If the distance between the sonar and the target is short, the time from when the sonar transmits the sound wave until it receives the reflected wave is short, and conversely, if the distance between the sonar and the target is long, the sonar transmits the sound wave and then the reflected wave. Will take longer to receive. Therefore, the distance between the sonar and the target can be expressed in various values by adjusting the delay time.

FIG. 6 is a diagram showing an example of the delay setting circuit 60 for performing the above-described operation, which is a kind of digital delay circuit in acoustic engineering, and the input wave is a low pass filter (LPF) 61. A / D converter 62 performs A / D conversion, and a delay setting signal is added to the D / A converter through the decoder 62, S-RAM (static RAM) 63, R / W control gate 64, etc. D / 64
It is A-converted and output as an output wave through a low-pass filter (LPF) 65.

FIG. 7 shows the operation when the delay time is variously changed by the delay setting circuit, and when the distance to the target is small as shown in FIG. If the distance to the target is medium,
By setting like (C), a case where the distance to the target is large can be expressed.

Further, by changing this with time, it is possible to express the state where the target is approaching or moving away. That is, when the delay time at a certain time thereafter is made smaller than the delay time at a certain time, it is possible to represent the situation where the target is approaching. On the contrary, when the delay time at a certain time after that is made larger than the delay time at a certain time, it is possible to represent a situation where the target is moving away.

FIG. 8 is a diagram showing the above-described usage. By using FIG. 8A, the case where the target is approaching is represented, and by using FIG. A case where the target is distant (away) can be expressed.

Next, the Doppler shift setting circuit 70 will be described. This is because when the sound source approaches, the frequency becomes higher, and when it separates (removes), the frequency becomes lower.By applying the Doppler effect, the frequency of the output sound wave is changed with respect to the frequency of the input sound wave, and the target The case of approaching and the case of separating are expressed by a single signal without changing the delay time at every certain time as shown in FIG.

FIG. 9 shows an example of the Doppler shift setting circuit 70, which is a kind of quadrature modulation / demodulation circuit in acoustic engineering, in which the cos wave is used as the I component of the input signal with a low pass filter (LPF) 71 interposed therebetween. It is multiplied by times, and the Q component is sin
The wave is multiplied twice by the cos wave with the low-pass filter (LPF) 72 interposed therebetween, and both are added again. By doing so, the frequency of the output sound wave can be made different from the frequency of the input sound wave.

FIG. 10 is a diagram showing an example using the above Doppler shift setting circuit 70. In FIG. 10A, the frequency of the output sound wave is higher than the frequency of the input sound wave (N kHz). (N + α kHz), (B)
Shows the case where the frequency of the output sound wave is lower (N-β kHz) than the frequency of the input sound wave (N kHz). The former expresses the case where the target object is approaching, and the latter expresses the case where the target object is moving away.

Next, the pulse expansion circuit 80 will be described. This is to change the pulse width and the pulse length of the output sound wave with respect to the input sound wave.
0 is for expressing the phenomenon that the output wave is prolonged with respect to the input wave when the sound wave hits a large object.

FIG. 11 shows an example of the pulse expansion circuit 80. This circuit is an acoustic reverberation (echo).
This is a kind of reverb circuit for obtaining the above, and the original waveform is appropriately amplified by the amplifier 81, added by the adder 83 via the delay device 82, and shaped by the envelope generation circuit 84. By using such a circuit, for example,
As shown in FIG. 12, an input wave having the same amplitude width from the beginning to the end can be changed to a spindle-shaped output wave having a small initial amplitude and a large intermediate amplitude.

The target strength setting circuit 50, the delay setting circuit 60, the Doppler shift setting circuit 70, and the pulse expansion circuit 80 described above can be used in appropriate combination.

Each of the above circuits is a non-analysis processing type circuit, which analyzes the input signal using FFT (Fast Fourier Transform) and processes it with a DSP (Digital Signal Processor) to output the output signal. It does not generate. Therefore, the power consumption is small, and as a result, the battery 11
The value of 0 can be reduced, the size of the entire device can be reduced, and the cost can be reduced.

In each circuit, it is necessary to adjust the set value as to how the output wave corresponds to the input wave. However, when the control box 100 is left on the seabed as in the present embodiment. When changing the setting position, pull out from the seabed, adjust the setting value to the desired value, and leave it on the seabed again.

On the other hand, as shown by the alternate long and short dash line in FIG. 1, the work boat 4 is arranged and the work boat 4 and the control box 100 are arranged.
It is also possible to change the set value of each circuit in the signal conversion device 30 via this cable 400 by connecting the above with the cable 300. Alternatively, although not shown, a sound wave for changing the set value may be transmitted and the set value may be changed via the sound wave.

Next, the use of the acoustic target 1 will be described. (1) Sonar development At the time of sonar development, it is necessary to confirm whether the sonar has the desired performance. At this time, it is very time consuming and expensive to dispatch a target such as a submarine every time, but by using this acoustic target,
For example, it is possible to test in a water tank,
It can save a lot of time and money. (2) Sonar operation training When a sonar is attached to a ship, training is required to familiarize operators with sonar operation. So every time,
Sending a target, for example, a submarine, takes a lot of time and money, but by using this acoustic target, various situations can be easily reproduced. (3) Deception of enemies in actual battle when used as a military ship (so-called decoy) Although not described in detail, the action of each circuit described above can cause the enemy to misidentify the state of its own ship.

Although the acoustic target for the active sonar in water has been described as an example, the idea of the present invention can be applied to an acoustic sonar in the air or a radar by radio waves.

[0037]

INDUSTRIAL APPLICABILITY The present invention relates to an acoustic target, and a wave receiver that receives an input sound wave emitted by a sonar and converts it into an electric input signal, and an electric input signal from the wave receiver into a desired output sound wave. A signal conversion device for converting into a convertible electric output signal, a wave transmitter for converting an electric output signal from the signal conversion device into a sound wave and transmitting an output sound wave, a signal conversion device, a wave receiver, The acoustic target comprises an electric power supply means for supplying electric power to drive the wave transmitter. According to the invention of claim 1, the signal conversion device prevents the operation time of the wave receiver and the wave transmitter from overlapping. The wave receiver and the wave transmitter are arranged close to each other, including the wave transmission duplication prevention means. Therefore, there is no risk of howling, and the overlapping operation time of the wave receiver and wave transmitter is prevented by the wave reception / duplication preventing means, so the wave receiver and wave transmitter can be placed close to each other and downsized. it can. Further, in the invention of claim 2, the signal conversion device is configured by a non-analytical wave-making circuit that does not include analysis processing of an input signal, power consumption can be reduced, and as a result, the capacity of the power supply means can be reduced. The whole can be miniaturized.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of the present invention.

FIG. 2 is a diagram showing a configuration of a signal conversion device.

FIG. 3 is a diagram for explaining an operation of a transmitted / received wave duplication prevention circuit.

FIG. 4 is a diagram showing an example of a target strength setting circuit.

5A and 5B are diagrams showing the operation of the target strength setting circuit, where FIG. 5A shows a case where the output wave is increased with respect to the input wave, and FIG. 5B is a case where the output wave is decreased with respect to the input wave. The case is shown.

FIG. 6 is a diagram showing an example of a delay time setting circuit.

FIG. 7 is a diagram showing the operation of the delay time setting circuit,
(A) represents a case where the time difference between the input wave and the output wave is small, and represents a case where the distance to the target object is small, and (B) represents a case where the time difference between the input wave and the output wave is medium. The case where the distance is medium is represented, and (C) shows the case where the time difference between the input wave and the output wave is large, and represents that the distance to the target object is large.

FIG. 8 is a diagram showing another operation of the delay time setting circuit, in which (A) represents a case where the time difference between the input wave and the output wave gradually decreases, and represents a case where the target object is approaching,
(B) shows the case where the time difference between the input wave and the output wave gradually increases, and the target object is separated (distanced).

FIG. 9 is a diagram showing an example of a Doppler shift setting circuit.

FIG. 10 is a diagram showing the operation of the Doppler shift setting circuit, in which (A) represents the case where the frequency of the output wave is higher than that of the input wave, and represents the case where the target object is approaching, and (B).
Represents the case where the frequency of the output wave is higher than the frequency of the input wave, and the case where the target object separates (removes).

FIG. 11 is a diagram showing an example of a pulse expansion circuit.

FIG. 12 is a diagram showing an operation of a pulse expansion circuit.

[Explanation of symbols]

1 ... Acoustic target 2 ... Sonar 10 ... Wave receiver 20 ... Transmitter 30 ... Signal converter 40 ... Receiving wave duplication prevention circuit 50 ... Target strength setting circuit 60 ... Delay time setting circuit 70 ... Doppler shift setting circuit 80 ... Pulse stretching circuit

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Claims (6)

[Claims] 1. A receiver which is an acoustic target and receives an input sound wave emitted by a sonar and converts it into an electrical input signal, and an electrical input signal from the receiver into a desired output sound wave. A signal converter that converts the electric output signal to a possible electric output signal, a wave transmitter that converts the electric output signal from the signal converter to a sound wave and emits an output sound wave, a signal converter, a receiver, and a transmitter. The signal converter includes power receiving means for supplying electric power for driving the wave receiver, and means for preventing the signal converter from overlapping the operating time of the wave receiver and the wave transmitter. An acoustic target, characterized in that wave filters are arranged in close proximity. 2. An acoustic target which receives an input sound wave emitted by a sonar and converts it into an electric input signal, and an electric input signal from the wave receiver into a desired output sound wave. A signal converter that converts the electric output signal to a possible electric output signal, a wave transmitter that converts the electric output signal from the signal converter to a sound wave and emits an output sound wave, a signal converter, a receiver, and a transmitter. An acoustic target, comprising a power supply means for supplying power to drive a wave device, wherein the signal conversion device is constituted by a non-analytical wave-making circuit that does not include analysis processing of an input signal. 3. The acoustic target according to claim 1, wherein the signal conversion device includes a target strength setting circuit capable of adjusting a target strength which is an intensity of an output sound wave with respect to an input sound wave. 4. The acoustic target according to claim 1, wherein the signal conversion device includes a delay time setting circuit capable of adjusting the transmission time of the output sound wave with respect to the reception time of the input sound wave. 5. The acoustic target according to claim 1, wherein the signal conversion device includes a Doppler shift setting circuit capable of changing the frequency of the output sound wave with respect to the frequency of the input sound wave. 6. The acoustic target according to claim 1, wherein the signal conversion device includes a pulse expansion circuit capable of changing the pulse width and pulse length of the output sound wave with respect to the input sound wave.