JPH068749B2 - Sound Intensity Water Meter - Google Patents

Description

The present invention relates to an acoustic intensity wattmeter having a sensor unit, an intensity calculation unit, and a display unit for sensing sound waves, and has a high efficiency and a configuration sound source search. Relates to sound intensity watt meters.

[Conventional technology]

High-accuracy search technology for noise sources is indispensable in order to economically measure equipment noise in a short time, and the acoustic intensity wattmeter has recently been attracting attention as a measuring instrument for this purpose. Conventionally, this kind of watt meter is composed of a pair of sound wave sensor units arranged opposite to each other, a support unit for the same, an intensity calculation unit, and a display unit showing the magnitude and direction of the resulting intensity. Things are known. This kind of watt meter is disclosed in, for example, Japanese Patent Laid-Open No. 58-28631, Institute for Industrial Science, University of Tokyo, Seiken Leaflet No. 1.
24 in the document entitled "Simplified Sound Intensity Watt Meter".

[Problems to be solved by the invention]

The above-mentioned conventional wattmeter is intended to measure the intensity direction and magnitude in the extension axis direction connecting a pair of sensors in principle. When detecting the sound source position direction, the center of the pair of sensors is centered. As a result, it is necessary to rotate the sensor by 90 °. In order to detect in a short time, a drive mechanism for rotating a pair of microphones, such as a motor and a gear or a belt, is indispensable. Moreover, since this mechanism needs to be located near the sensor, the sound generated by the motor and the gear is generated. It can be easily estimated that the noise becomes noise and the search accuracy is significantly reduced. Furthermore, if a drive machine is installed, the radius of gyration becomes large, so it is not applicable when exploring a sound source in a small space, or when targeting a device whose sound volume or sound source position changes temporally. However, there was a problem that the accuracy deteriorated significantly.

An object of the present invention is to provide an acoustic intensity wattmeter capable of detecting the position of a sound source by measuring the direction and magnitude of the acoustic intensity with high accuracy in a short time.

[Means for solving problems]

The above object of the present invention is basically to provide a first pair of sensors and a first pair of sensors so as to be able to detect the direction of a sound source.
To be almost orthogonal to the straight line connecting the sensing parts of the pair of sensors,
A second pair of sensors is provided, and further a third pair of sensors is provided so as to pass through substantially the center of the first and second pair of sensors and intersect vertically, and these three pairs of sensors are provided. This is achieved by combining a calculation unit that analyzes the intensity based on the output signal and a display unit that indicates the propagation direction and the magnitude of a sound wave by combining these three pairs of calculation output results.

[Action]

It is possible to detect the propagation direction and the magnitude of the sound wave immediately and in real time by synthesizing the intensity and direction of each pair of directions obtained by using, for example, three microphone outputs.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an example of an external view of an intensity watt meter. The watt meter supports a sensor unit 1 and a support 2 for supporting the sensor unit 2, one end of the support 2, and a hand box unit 5 having a display unit 4, a display switching switch 3, and an intensity calculation circuit unit 7. It is composed of an arithmetic unit box 9 for accommodating the power source unit 8, a hand box 5 and a communication cable 6 between the arithmetic box 9. FIG. 2 shows a configuration in which the sensor unit is separated and the arithmetic unit and the display unit are used as an intensity analysis device. Electrical signal 10 recorded on taper recorder etc.
And a box portion 5 having a connector 2'for inputting the signal and an operation box portion 9. FIG. 3 shows the structure of the sensor unit. The sensor unit includes intensity measurement sensors 11 and 12 for the X component in the axial direction of the support 2 and a measurement sensor 1 for the Y component in the direction orthogonal to these sensors.
3 and 14 and sensors 15 and 16 for measuring a Z component in a direction perpendicular to the axes of these two sensors. Sensors 11 and 12, sensors 13 and 14, and sensors 15 and 16
Are provided so as to face each other, intersect at right angles, and intersect with each other.
The sensors 11 to 16 are small-sized electret microphones, and further, a spacer 17 is arranged to keep the distance between these microphones constant. FIG. 4 is an enlarged view of the display unit 4 housed in the hand box 5, and the two-dimensional component (X, Y direction) of the sound flow direction is indicated by an arrow (vector).
A plurality of LEDs 19 indicated by are arranged on a concentric circle. On the other hand, two LEDs 20 for identifying the flow of sound in the Z direction (up and down direction) are installed above the LED 19. FIG. 5 shows another embodiment of the display unit 4 shown in FIG. Here, a plurality of LEDs 20 for displaying the Z component indicating the vertical flow of sound are arranged in the vicinity of the LED 19. FIG. 6 is a block diagram of the intensity calculation block and the display unit. The outputs A of the first microphones 11 and 12 and the second pair of microphones 13 and 14
Output B and output C of the third pair of microphones 15 and 16 for amplification and impedance matching buffer unit 2
1. A circuit 22 for calculating intensity components I _X , I _Y , I _Z in the X, Y and Z directions from the A, B and C signals, and a direction from these values I _X , I _Y , I _Z (Arrow) and a multiplication unit 31 for calculating the magnitude thereof, a circuit 23 including a division unit 25 to 27 for obtaining each direction component and a switching unit 28 for switching the direction component, for displaying the result by an LED. It is composed of circuits 29 and 30. The intensities I _X , I _Y , and I _Z in the X, Y and Z directions can be represented by the product of the sound pressure P (t) and the particle velocity (t) of the microphone signals facing each other. Here, since the particle velocity (t) is proportional to the spatial gradient of the sound pressure of the two microphone signals, the calculation shown by the following equation is realized by the electric circuit.

Here, ρ is the density of air, Δr ₁ , Δr ₂ , Δr ₃ are the distances between the microphones of each pair, and p _{11 to} p ₁₆ are the output sound pressures of the microphones 11 to ₁₆ . The present invention has the above-described configuration, and the microphones 11 and 12 facing each other and the microphones 13 and 14 that are orthogonal to the microphones 11 and 12 are provided, and the microphones 15 and 16 that vertically intersect with these microphones are also provided. The present invention is characterized by providing a display section that indicates the propagation direction and the magnitude of a sound wave by synthesizing the magnitude and direction of the intensity in each pair of directions obtained by using the microphone output signal of. In addition, even when the microphone is removed, the analysis device has a feature of being able to calculate and display the intensity by inputting some electric signal. The drive mechanism for rotating the microphone, which was required in the past, is no longer necessary, and the intensity, that is, the direction of sound flow can be known at a time, so the direction of the sound source can be detected at any time. As a result, a highly accurate search is realized for moving sound sources and sound sources whose size changes with time. If an analog circuit, particularly an analog filter such as a switched capacity filter is used in the arithmetic unit, sound source detection for each frequency band can be performed in real time. The microphones shown in the above embodiments are electret-type condenser microphones, which are miniaturized such that they do not need to constantly supply a DC voltage and do not require a preamplifier for impedance conversion, but three pairs of microphones are orthogonal and crossed. Other types of microphones that can be configured to exhibit the same effect as the present invention. Further, in the embodiment, an internal power supply unit for driving an electric circuit is used in the arithmetic unit box, and this power supply unit is a dry battery or a dry battery for charging, which is suitable for a wattmeter of a portable specification for a site, but from the outside. A drivable power source is also included in the present invention.

〔The invention's effect〕

As described above, according to the intensity wattmeter of the present invention, the direction and magnitude of the sound, that is, the vector can be quantitatively grasped, so that the direction of the sound source can be detected immediately from this flow direction in real time. Moreover, it is possible to detect a sound source whose size and position are changed with high accuracy. Although the number of systems of the arithmetic unit is three times that of the conventional method, the size and weight of the conventional wattmeter are hardly affected by the recent LSI integration technology and the like, which enables downsizing and low power consumption.

[Brief description of drawings]

FIG. 1 is an external view of an intensity watt meter of one embodiment of the present invention, FIG. 2 is an external view of an intensity watt meter of another embodiment, FIG. 3 is a configuration diagram of a sensor section, and FIG. FIG. 5 is an enlarged view of the display part in the hand box shown in FIG. 1, FIG. 5 is another embodiment of FIG. 4, and FIG. 6 is a block diagram of the intensity calculation block and the display part. 1 ... Sensor part, 2 ... Support, 4 ... Display part, 5 ... Hand box part, 7 ... Intensity calculation circuit, 9 ... Calculation part box, 17 ... Spacer, 18 ... Size and direction calculation part, 19 ... Vector display Part (LED), 20 ... Vertical display part, 12 ... Buffer part, 22 ... Intensity calculation circuit.

Claims (7)

[Claims] 1. A sound intensity sensor, a sound intensity calculator, and a sound intensity wattmeter from a result display unit, wherein a first pair of sensors and a straight line connecting between the first pair of sensors. Providing a second pair of sensors substantially orthogonal and passing through the center between the first pair of sensors;
In addition, the third sensor 1 passes through substantially the center between each pair of sensors and intersects with the same line connecting the sensors of each pair in a straight line.
A pair of sensors is provided, and a computing unit that computes the magnitude and direction of the intensity obtained using the output signals of the pair of sensors, and the direction or direction of the sound intensity based on the output signal of the computing unit. A sound intensity watt meter, comprising: a display unit for indicating the size of the sound intensity watt meter. 2. The sound intensity wattmeter according to claim 1, wherein at least one pair of sensors of the sound wave sensor section are arranged such that their sound receiving surfaces face each other. 3. The sound intensity wattmeter according to claim 1 or 2, wherein the acoustic wave sensor is an electret condenser microphone. 4. The sound intensity wattmeter according to any one of claims 1 to 3, wherein the arithmetic unit is composed of an analog circuit. 5. The sound intensity wattmeter according to any one of claims 1 to 4, wherein the display section has a digital display function. 6. The sound intensity wattmeter according to claim 1, wherein the display unit has a switching device for one-dimensional sound source direction identification and a display function. . 7. The sound intensity wattmeter according to claim 1, wherein the intensity wattmeter is powered by an internal power source.