JPH026778A - Detecting device for moving noise source - Google Patents

Abstract

PURPOSE:To improve the discriminating capacity against a target sound source and to decrease a malfunction by receiving an acoustic signal from a moving noise source and converting this acoustic signal to an electric signal. CONSTITUTION:First of all, when an acoustic signal from a noise source enters into a receiver 11, its signal is converted to an electric signal and amplified by an amplifier 12. The amplified signal is inputted to the first and the second band pass filters 13, 19, and only the respective frequency components being different from each other are filtered. The signals which have been filtered are detected by the first and the second detecting circuits 14, 20, respectively. Subsequently, the signals which have been outputted from the circuits 14, 20 are inputted to the first and the second comparing circuits 15, 21, respectively, compared with a detection reference level, and in case when they have exceeded the detection reference level, detecting signals are outputted from the circuits 15, 21, respectively. The detecting signals which have been outputted from the circuits 15, 21 are inputted to a logic circuit 18, respectively. In this case, only when the detecting signals have been inputted from both the circuits 15, 21, the circuit 18 outputs a signal of a fact that a noise source has been detected.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a mobile noise source detection device for receiving noise emitted from a mobile noise source such as a ship, and identifying the mobile noise source. The present invention relates to the detection system.

(Prior Art) Conventionally, there has been a technology in this field as shown in FIG. 2, for example. The configuration will be explained below using figures.

FIG. 2 is a block diagram showing an example of the configuration of a conventional moving noise source detection device. Traditionally, devices of this type have been intended for a single frequency range.

This moving noise source detection device includes a receiver 1, an amplifier 2, a bandpass filter 3, a detection circuit 4, and a reference level generation circuit 5.
, and a comparison circuit 6. The receiver 1 is for receiving noise emitted from a moving noise source as an acoustic signal and converting it into an electrical signal.

Amplifier 2 amplifies the electrical signal output from receiver 1,
This is output to the band pass filter 3.

The bandpass filter 3 and the detection circuit 4 are connected to a detection circuit 7.
It constitutes. The bandpass filter 3 filters the amplified electrical signal, and only signals in a specific frequency range are passed to the detection circuit 4, which detects the input signal.

The reference level generation circuit 5 generates a preset detection reference level and outputs it to the comparison circuit 6.

The comparison circuit 6 compares the level of the input signal from the detection circuit 4 with a detection reference level, and outputs a detection signal when the human input signal level exceeds the level. A moving noise source is detected by outputting this detection signal.

In the moving noise source detection device configured as above,
For example, if the receiver 1 is installed underwater, it becomes possible to identify the type of ship or the like or to understand the navigational status by detecting the sound of the propeller or engine of the ship.

(Problems to be Solved by the Invention) However, in the moving noise source detection device having the above configuration, since a single frequency region is targeted for detection, there is a problem that malfunctions are likely to occur.

That is, if a moving noise source other than the target sound source emits sound waves in the same frequency range, there is a risk that the emitted sound will be detected and mistakenly recognized as the target sound source. In addition, relatively low-frequency noise, which is mainly common to underwater radiated sound, is
It has a frequency band close to the typical spectrum of earthquakes and explosions, which could also cause malfunctions.

The present invention provides a moving noise source detection device that solves the problem of the prior art, which tends to cause malfunctions because it detects a single frequency range.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a receiver that receives an acoustic signal from a moving noise source and converts the acoustic signal into an electrical signal, and a receiver that receives an acoustic signal from a moving noise source and converts the acoustic signal into an electrical signal. a first detection circuit that detects a specific frequency component and outputs it as a first detection signal;
a first reference level generation circuit that outputs a set first detection reference level; and a first reference level generation circuit that outputs a first detection signal by comparing the first detection signal and the first detection reference level. a second detection circuit that detects a frequency component different from the specific frequency component from the electric signal and outputs it as a second detection signal; a second reference level generation circuit that outputs a second detection reference level; and a second comparison circuit that compares the second detection signal and the second detection reference level and outputs a second detection signal. and a logic circuit for detecting the noise source based on the first detection signal and the second detection signal.

(Function) According to the present invention, since the moving noise source detection device is configured as described above, the second detection circuit detects signal components in a different frequency range from the frequency components detected by the first detection circuit. , and outputs it to the second comparison circuit. Second
The comparison circuit compares the input signal from the second detection circuit with a second detection reference level, and outputs a second detection signal to the logic circuit when the input signal level exceeds the reference level. do the work. Further, the logic circuit functions to output a signal indicating that the noise source has been detected only when the first and second detection signals are input.

These functions make it possible to confirm the presence of a moving noise source by detecting signals in two different frequency regions. Once done, the above problem can be solved.

(Embodiment) FIG. 1 is a block diagram of a moving noise source detection device showing an embodiment of the present invention.

This moving noise source detection device includes a receiver 11 that receives an acoustic signal radiated from a moving noise source and converts it into an electrical signal. An amplifier 12 is connected to the wave receiver 11, and a first bandpass filter 13, a first detection circuit 14, and a first comparison circuit 15 are connected to the amplifier 12 in this order. A first detection circuit 16 is configured by the first bandpass filter 13 and the first detection circuit 14 . Further, the first reference level generation circuit 17 is connected to the input terminal of the first comparison circuit 150.

The configuration up to this point is similar to the conventional moving noise source detection device, but the difference is that the output side of the first comparison circuit 15 is connected to the logic circuit 1B. The logic circuit 18 has a circuit configuration that receives two types of input signals and, for example, calculates the AND of the two types of input signals.

On the output side of the amplifier 12, a second bandpass filter 19, a second detection circuit 20, and a second comparison circuit 21 are provided.
or connected sequentially. Second bandpass filter 19
and the second detection circuit 20 constitute a second detection circuit 22. A second reference level generation circuit 23 is connected to the input side of the second comparison circuit 210, and an output side of the second comparison circuit 21 is connected to the input side of the logic circuit 18.

The second band-pass filter 19 filters a signal in a frequency range different from that of the first band-pass filter 13 among the electrical signals amplified by the amplifier 12, and sends the output signal to a second detection circuit 20. is detected. The second reference level generation circuit 23 generates a detection reference level and outputs it to the second comparison circuit 21. Second comparison circuit 21
is the second detection circuit 20 and the second reference level generation circuit 2
3 is compared, and if the output signal level of the second detection circuit 20 exceeds the output signal level, a detection signal is output.

The moving noise source detection device configured as described above operates as follows.

First, when an acoustic signal from a noise source enters the receiver 11, the signal is converted into an electrical signal and amplified by the amplifier 12. The amplified signal is input to first and second bandpass filters 13.19, each of which filters only specific, different frequency components. The filtered signals are detected by first and second detection circuits 14.20, respectively.

The signals output from the first and second detection circuits 14.20 are input to first and second comparison circuits 15.21, respectively, and are input to first and second reference level generation circuits 17.21, respectively.
It is compared with the detection reference level from 23. At that time, the first
When the output signal levels of the and second detection circuits 14 and 20 exceed the detection reference level, the comparator circuit 15
A detection signal is outputted from each of the terminals 21 and 21.

The detection signals output from the first and second comparison circuits 15 and 21 are input to the logic circuit 18, respectively. In this case, the logic circuit 18 outputs a signal indicating that a noise source has been detected only when detection signals are input from both comparison circuits 15 and 15.21. That is, signals in two different frequency regions are checked, and only when the presence of both signals is confirmed, a noise source detection signal is finally output.

Therefore, even if a signal that matches in a single frequency range is emitted from a sound source other than the target sound source, there is no risk of misidentifying it as the target sound source if it differs in other frequency ranges, and the ability to identify the target sound source is significantly improved. do.

Note that the present invention is not limited to the illustrated embodiment, and can be modified in various ways, such as the following modifications.

(1) In FIG. 1, the first and second detection circuits 16
．． 22 is made up of first and second bandpass filters 13.19 and first and second detection circuits 14.20, respectively, but it is also possible to have a configuration other than a combination of these.

(2) Although the logic circuit 1B in FIG. 1 has a circuit configuration that takes logical products, other configurations may be used. For example, it can also be configured by a combination of OR circuits.

(3) The receiver 11 and the amplifier 12 may have a configuration other than that shown in the drawings. For example, a plurality of receivers 11 may be provided. Furthermore, various types of receiver 11 can be used depending on the purpose, such as an underwater receiver. Furthermore, the term "noise source" as used in the present invention refers to sound sources in a broad sense, including not only audible sounds but also ultrasonic waves and the like.

(4) Although the present invention deals with acoustic signals in two types of frequency ranges, it is also possible to create a device that can deal with three or more types of frequency ranges based on the spirit of the present invention.

(Effects of the Invention) As described above in detail, according to the present invention, the moving noise source detection device is provided with the second detection circuit, the second reference level generation circuit, and the second comparison circuit. Since a logic circuit is provided by connecting to the first and second comparison circuits,
Moving noise sources can be identified by detecting acoustic signals in two frequency ranges.

Therefore, by improving the ability to identify the target sound source, malfunctions can be reduced, and an extremely reliable moving noise source detection device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a moving noise source detection device showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of the configuration of a conventional moving noise source detection device. 11... Receiver, 13.19... First
and a second bandpass filter, 14.20...
- First and second detection circuits, 15.21... First and second comparison circuits, 16.22... First and second detection circuits, 17.23. ...First and second reference level generation circuits, 1B...Logic circuit.

Claims (1)

[Scope of Claims] A receiver that receives an acoustic signal from a moving noise source and converts the acoustic signal into an electrical signal, and detects a specific frequency component of the electrical signal and outputs it as a first detection signal. First thing to do
and a first reference level generation circuit that outputs a set first detection reference level, and generates a first detection signal by comparing the first detection signal and the first detection reference level. and a first comparison circuit that outputs a second detection signal, a second detection device that detects a frequency component different from the specific frequency component from the electric signal and outputs this as a second detection signal. a second circuit for outputting a second detection reference level;
a reference level generation circuit, and a second comparison circuit that compares the second detection signal and the second detection reference level and outputs a second detection signal; A moving noise source detection device comprising a logic circuit for detecting the noise source based on the second detection signal.