JPS61256226A - Acoustic intensity wattmeter - Google Patents

Abstract

PURPOSE:To enable the detection of the sound source position, by arranging a pair of sensors and additional pair of sensors roughly parpendicular to the extension connecting the sensing sections of these sensors to measure the direction and the size of the acoustic intensity in a short time at a high accuracy. CONSTITUTION:A sensor section comprises sensors 8 and 9 for measuring the intensity of X component axial to a support 2 and sensors 10 and 11 for measur ing the intensity of Y component parpendicular to the shaft of the support 2 in such a manner that the sensors 8 and 9 face the sensors 10 and 11 while parpendicular thereto. The amplification and impedance matching of the outputs A and -A of the sensors 8 and 9 and the outputs B and -B of the sensors 10 and 11 are down with a buffer section 13. Then, an intensity computing circuit 14 computes intensity components X and Y respectively in the directions X and Y from the signals of the outputs A and -A and B and -B. Moreover, the size and the direction of the intensity are computed from values X and Y with a multiplying section 15 and a dividing section 16 and the results are LED displayed on circuits 18 and 19. In this manner, a highly accurate detection can be done by combining the size and direction of the intensity obtained using two systems of microphone output signals.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an acoustic intensity wattmeter having a sensor section, an intensity calculation section, and a display section for sensing sound waves, and is capable of detecting sound sources with high efficiency and high precision. The present invention relates to a sound intensity wattmeter suitable for use.

[Background of the invention]

High-accuracy detection technology for noise sources is essential in order to implement noise countermeasures for equipment quickly and economically, and acoustic intensity wattmeters have recently attracted attention as a measuring device for this purpose. Conventionally, this type of wattmeter has been composed of a pair of sonic sensor sections disposed opposite to each other, a support section for the sonic sensor sections, an intensity calculation section, and a second indicator section that indicates the magnitude and direction of the resulting intensity. What is known is that the University of Tokyo Institute of Industrial Science, IB Leaflet A
Ant simple acoustic intensity meter in 124'
It is discussed in the article entitled.

However, in principle, this type of meter measures the direction and magnitude of the intensity in the direction of the extension axis connecting a pair of sensors, and when detecting the direction of a sound source position, the center of the sensor is the center of the sensor. As such, it is necessary to rotate the sensor 180°. In order to detect in a short time, a drive mechanism such as a motor and gears or a belt to rotate the pair of microphones is essential, and since this device must be installed near the sensor, the noise generated by the motor and gears is essential. It can be easily estimated that the sound produced by the sensor becomes noise and greatly reduces exploration accuracy. Furthermore, if a drive mechanism is provided, the rotation radius will become larger, making it impossible or impossible to apply it when searching for a sound source in a narrow space or when targeting equipment where the noise level or position of the sound source changes over time. However, there was a problem in that the accuracy deteriorated significantly.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sound intensity wattmeter that can measure the direction and magnitude of sound intensity with high accuracy in a short time and detect the position of a sound source.

[Summary of the invention]

In order to achieve the above object, the present invention basically makes it possible to detect the direction of a sound source.
Furthermore, a pair of sensors is provided, and a calculation unit that can analyze the intensity based on the output signals of these two pairs of sensors and the calculation output results of these two pairs are combined to determine the propagation direction and magnitude of the sound wave. It consists of the display section shown in FIG.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. FIG. 1 shows an external view of the intensity wattmeter. The wattmeter includes a sensor section 1, a support 2 for supporting the sensor section, a hand box section 4 that supports one end of the support 2 and has a display section 3, an intensity calculation circuit section 5, and a power supply section 6. arithmetic unit box 7 and communication cable 8 between the local box 4 and the arithmetic box 7
It consists of FIG. 2 shows the configuration of the sensor section.

The sensor section includes a sensor 8.9 for measuring the intensity of the X component in the axial direction of the support 2, and a sensor 10.11 for measuring the y component in the direction orthogonal to the axis of the support 2.
9 and sensors 10 and 11 are provided so as to face each other and to be perpendicular to each other. The sensors 8 to 11 are small electret microphones, and a spacer 12 is provided to keep the distance between these microphones constant. Third
The figure shows a block diagram of an intensity calculation block and a display section. Outputs A and A of microphones 8 and 9 and output B of the other pair of microphones 10 and 11.

A buffer unit 13 for amplifying and impedance matching A, a circuit 14 for calculating intensity components X and Y'e in the X and y directions from the A, B, and B signals, and a circuit 14 for calculating the intensity components X and Y'e in the X and y directions from the A, B, and B signals,
Multiplication unit 15 that calculates the direction (arrow) and its size from Y
20% of the circuit consists of the 2 division section 16, and 20% of the circuit consists of circuits 18 and 19 for displaying the result on the t-LED. The intensities Ix and Iy in the X and y directions can be expressed as the product of the sound pressure p(t) of the opposing microphone signals and the particle velocity V(t), respectively. Here, since the particle velocity v(t) is proportional to the spatial gradient of the sound pressure of the two microphone signals, the calculation shown in the following equation is realized by an electric circuit.

Here, ρ is the air density, Δrl+Δr2 is the distance between each pair of microphones, and p8 to p11 are the output sound pressures of the microphones 8 to 11.

FIG. 4 is an enlarged view of the display unit 3 housed in the hand box 4, in which a plurality of LEs 21 are arranged concentrically and on top of each other to indicate the direction of sound flow with arrows (vectors). Further, an LED 20 for displaying the intensity level is also provided at the center of these LEDs. The present invention has the above-mentioned configuration, and includes microphones 8 and 9 facing each other and microphones 10 and 11f arranged orthogonally thereto, and the intensity in the direction of each pair obtained by using the microphone output signals of these two paths. The device is characterized by a display section that combines the magnitude and direction of the sound wave and shows the propagation direction and magnitude of the sound wave. There is no longer a need for a driving mechanism for rotating the microphone, which was required in the past, and since the intensity, that is, the direction in which the sound flows, can be determined at once, the direction of the sound source can be detected at any time.

As a result, we have achieved high-precision detection of moving sound sources and sound sources whose size changes over time. If an analog circuit, particularly an analog filter, such as a switched capacity filter, is used in the calculation section, it becomes possible to detect the sound source in each frequency band in a short time. The microphone shown in the above example is
It is an electret type condenser microphone, which does not require constant supply of DC voltage and does not require a preamplifier for impedance conversion, making it more compact, but other types of microphones can be configured so that two pairs of microphones are orthogonal to each other. If so, the same effect as the present invention is exhibited.

Furthermore, in the embodiment, an internal 1E power source for driving the air conditioning circuit is used in the calculation unit box, and this power source is a dry cell or a rechargeable dry cell, which is suitable for a portable type wattmeter for field use. A precept source that can be driven from the outside is also included in the present invention. In addition, in the embodiment shown in Fig. 2, a pair of microphones are provided to face each other, but depending on the shape and size of the space required for exploration, two microphones as shown in Fig. 5 may be used.
The present invention also includes a sensor configured of a pair of microphones arranged in parallel and a pair of microphones orthogonal to the pair of microphones.

〔Effect of the invention〕

As explained above, according to the intensity wattmeter of the present invention, the direction and magnitude of the sound, that is, the vector, can be quantitatively determined, so the direction of the sound source can be detected immediately and in real time from the flow direction. Moreover, it can detect sound sources that change in size and position with particularly high accuracy. The calculation unit has twice the number of systems compared to the conventional method, but
Recent LSI integration technology has made it possible to achieve smaller size and lower power consumption, which has almost no effect on the size and weight of conventional wattmeters.

[Brief Description of the Drawings] Fig. 1 is an external view of the intensity wattmeter of the present invention, Fig. 2 is a configuration diagram of a part of the sensor, Fig. 3 is a block diagram of the intensity calculation block and display section, and Fig. 4 1 is an enlarged view of the display section in the hand box shown in FIG. 1, and FIG. 5 is another configuration diagram of a part of the sensor shown in FIG. 2. DESCRIPTION OF SYMBOLS 1... Sensor part, 2... Support, 3... Display part, 4... Hand box part, 5... Intensity calculation circuit part, 7... Calculation unit box, 12...・Spacer, 13... Buffer section, 14... Intensity calculation circuit, 17... LED display section, 20... Size and direction calculation section, 21... Vector display section (LED
＞Fang 1 Kuni Diagram 2

Claims (1)

[Scope of Claims] 1. A sound intensity wattmeter consisting of a sound wave sensor section, a sound intensity calculation section, and a result display section, which includes a pair of sensors and a direction substantially orthogonal to the extension direction of these sensors; A pair of sensors is further provided so as to pass through the center of the pair of sensors, and the direction or direction of the sound intensity is determined from the calculation results of the magnitude and direction of the intensity obtained using the sensor output signals of each pair. A sound intensity wattmeter characterized by being provided with a display section that indicates the size. 2. Claims characterized in that the sound wave sensor section is composed of a pair of sensors arranged opposite to each other and a further pair of sensors so as to be substantially perpendicular to the direction of extension of these sensors. A sound intensity wattmeter according to paragraph 1. 3. The sound intensity wattmeter according to claim 1 or 2, wherein the sound wave sensor is comprised of an electret condenser microphone. 4. The sound intensity wattmeter according to claim 1, 2, or 3, wherein the arithmetic unit is mainly composed of an analog circuit. 5. The sound intensity wattmeter according to claim 1, 2, 3, or 4, wherein the display section has a digital display function such as an LED or liquid crystal display. 6. The sound intensity wattage according to claim 1 or 2 or 3 or 4 or 5, wherein the intensity wattmeter is powered by an internal power source. meter.