JPH068751B2 - Sound Intensity Water Meter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acoustic intensity Wattometer having a sensor unit for sensing sound waves, an intensity calculation unit, and a display unit, and has a high efficiency and high precision sound source. The present invention relates to an acoustic intensity wattmeter improved for exploration.

[Conventional technology]

In order to take measures against noise of equipment economically in a short period of time, a high-accuracy exploration technology with a noise limit is indispensable, and an acoustic intensity Wattometer has recently attracted attention as a measuring instrument for this purpose. Conventionally, this type of Wattometer is composed of a pair of sound wave sensors arranged to face each other, a support section thereof, an intensity calculation section, and a display indicating the magnitude and direction of the resulting intensity. Are known. That is, it is discussed in the literature entitled "Simple Sound Intensity Wattmeter" in the Institute of Industrial Science, Institute of Industrial Science, Institute of Industrial Science, Institute for Industrial Science, Leaflet No.124.

[Problems to be solved by the invention]

However, in principle, this kind of meter measures the direction and magnitude of the intensity in the direction of the extension axis connecting the pair of sensors, and when detecting the direction of the sound limit position, the center of the pair of sensors is measured. It is necessary to rotate the sensor 180 ° around the center. In order to detect in a short time, a drive mechanism for rotating a pair of microphones, for example, a motor transmission mechanism (gear or belt) is indispensable. Moreover, since it is necessary to position this mechanism in the vicinity of the sensor, it can be easily inferred that the sound generated from the motor and the gear becomes noise and the search accuracy is greatly deteriorated. In addition, if a drive mechanism is installed, the radius of gyration will increase, making it impossible to apply when exploring a sound source in a narrow space, or when targeting a device whose sound volume or sound source position changes over time. There was a problem that the accuracy was very poor even if it was applied. There is also a problem that the absolute orientation at the measurement point is unknown.

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

[Means for solving problems]

In order to achieve the above object, the present invention basically forms an angle of 45 degrees, 90 degrees, or 135 degrees with an extension direction connecting a pair of sensors and their sensing portions so that the direction of a sound source can be detected. 3 pairs of sensors are provided on the same plane, and these 4
An arithmetic unit capable of analyzing the intensity based on a pair of sensor output signals and an arithmetic output result of the four pairs are combined to form a display unit showing the propagation direction and magnitude of a sound wave.

[Action]

In the sound intensity Wattometer configured as described above, the magnitude and direction of the intensity (direction at the measurement point and absolute direction) of each pair of directions obtained by using the outputs of the sensors (for example, microphones) of the multiple paths. ) Is synthesized, the sound wave propagation direction and its magnitude can be detected immediately and in real time.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows an external perspective view of the intensity water meter. The Wattometer of this example includes a sensor unit 1, a support 2 for supporting the sensor unit, a hand box unit 5 that supports one end of the support 2 and has a display unit 4, a display switching switch 3, and an intensity calculation circuit unit. 7
And a communication unit box 9 for accommodating the power supply unit 8 and a communication box 6 between the handy box 5 and the calculation 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. It is composed of an electric signal 10 recorded on a tape recorder and the like, a hand-held box section 5 having a connect 2'for inputting this signal, and a calculation box section 9.

The sensor unit 1 of FIG. 1 includes an intensity measurement sensor 11 and 12 for the Y component of the support 2 in the axial direction, measurement sensors 13 and 14 in the 45-degree direction with these sensors, and an X-direction in the 90-degree direction. Measuring sensors 15 and 16 and measuring sensors 17 and 18 of 135 degrees are provided. Sensors 11-1
A small electret microphone 8 is provided with a spacer 19 for keeping a constant interval between these microphones. FIG. 3 is an enlarged view of the display unit 4 housed in the hand-held box 5, in which a plurality of LEDs 20 for indicating two-dimensional components (X, Y directions) in the sound flow direction by arrows (vectors) are arranged on a concentric circle. Individually arranged. Also,
An LED 21 is provided at the center of these LEDs to display the intensity of the intensity. Furthermore, an LED 22 for indicating the absolute direction is also provided.

FIG. 4 shows a pair of sensors 11, 1 provided in the Y-axis direction.
2 shows a directional characteristic of 2. In the case of a pair of sensors, the sensitivity is good in the axial direction. FIG. 5 shows a pair of sensors 11 and 12 in the Y-axis direction shown in FIG.
A pair of sensors 13 and 14 provided in the same direction, and 90
The directional characteristics are shown when the sensors 15 and 16 in the direction of degrees and the sensors 17 and 18 in the direction of 135 degrees are provided. In this case, the sensitivity is improved in a region where two pairs of directional characteristics whose directions are adjacent to each other overlap each other. Therefore, in the case of the intensity measurement at the sensor position shown in FIG. 5, the sound source direction indication is Y for the sound wave incident from the Y-axis direction.
It does not show the axial direction accurately, but shows the direction of high sensitivity in which the directional characteristics of each sensor overlap, and the directional characteristics are improved in almost all directions. FIG. 6 shows a block diagram of the intensity calculation unit and the display unit for determining the incident direction of sound. Also, the seventh
The figure shows the directional characteristics of a pair of sensors. Intensity X-axis and Y-axis components I _X , where α is the incident angle of the sound wave,
Since I _Y is I _X = | I | ocsα and I _Y = | I | sin α, the magnitude | I | Therefore, the angle α can be obtained from tan α = | I _Y / I _X | or cot α = | I _X / I _Y | and the sign relation of I _X and I _Y. FIG. 8 shows an example in which the entire circumference is divided into 36 by 10 degree bits to calculate and display. A signal is picked up by two pairs of sensors and the signals | X | and | Y | after the intensity calculation are divided by a divider 23. In this case, the magnitude | I of | I _X | and | I _Y || I _Y / I _X | obtained by the comparator 24 | I
_{Based on} the determination result of _Y / _IX | or any operation is performed. This value is compared with the output value of the angle-equivalent voltage generating circuit 25 by the comparators 26a to 26d, and this output is input to the memory 27 as a digital signal 4bit. In this embodiment, the output voltage of the angle-equivalent voltage generation circuit 25 is
It corresponds to the values of tan10 °, tan20 °, tan30 °, tan40 °.

On the other hand, 0 ≦ | I _Y / I _X | ≦ 1 or 0 ≦ | I _X / I _Y | ≦ 1
Since there are eight display areas in the direction corresponding to, the comparator 24, the code inversion circuits 28a and 28b, and the code determination circuit 2 are used to specify a certain area out of the eight display areas.
9,30 using, I _X, -I _X, to digital converted to a signal representing the magnitude of I _Y, each of the code and I _X and I _Y of -I _Y. When these signals and the above 4-bit signal are input to the memory 27 as addresses, the memory 2 is previously stored.
A binary signal (6 bits) corresponding to the area of 36 divisions, which is written in 7 and has a 10 degree pitch around the entire circumference, is output.
The decoder 31 and the driver circuit 32 in FIG.
A circuit for converting a binary number into at least a 36-ary number and a circuit for driving an LED in a direction corresponding to this output.
The elements used in the arithmetic unit of the present embodiment are low-priced ICs, and are small-sized general-purpose products. Moreover, since the calculation time is extremely short, it is possible to realize a portable intensity meter that can calculate and display in real time. As described above, the direction operation unit in the Wattometer according to the present embodiment includes four pairs of intensity signal comparators, a sign inversion circuit and a sign discrimination circuit, a division circuit, a memory circuit, and a decoder circuit. The ratio of the magnitudes of the intensity signals I _X and I _Y , the sign of each signal, and the determination result of the magnitude are converted into a digital signal of a binary number, and a region in which the entire circumference is divided into 8 is a digital corresponding to an angle. By performing the operation of converting into a signal, the operation and display can be performed by extending the sound flow direction in the plane over the entire circumference. In the present embodiment shown in FIG. 8, the sign inverting circuit 28 and the sign discriminating circuit 33 are used, but the sign discriminating circuits 29 and 30 set the signs of I _X and I _Y to 0 or 1.
Since it has a function of converting into a digital signal, the sign inversion circuits 28a and 28b and the sign discrimination circuit 33 are not always necessary. When the directional characteristics of the pair of sensors depend on the frequency, it is effective to change the signal voltage output by the angle-equivalent voltage generating circuit 25 for each frequency band, and this is included in the present invention. Further, the method of dividing and displaying into 36 pieces in 10 pitches all over the circumference has been described in the embodiment, but the analysis display is not limited to the whole circumference, and the number of divisions is not particularly limited.

As shown in the block diagram of FIG. 6, the device of the present embodiment has the outputs A of the sensors 11 and 12, and the other pair of sensors 13 ,.
The output B of 14 and the outputs C of the sensors 15 and 16,
And the output D of the sensors 17 and 18, the buffer section for amplification and impedance matching, the above A, B ,.
A circuit for calculating intensity components I _a , I _b , I _c , and I _d in the A, B, C, and D directions from the C, D signals (intensity calculation unit), and the values I _a , I _b , I _c , I _d
Direction (arrow) and an intensity multiplication unit that calculates the magnitude of the direction, a calculation unit that includes each direction discriminator, and a vector calculation unit that performs logarithmic conversion of the direction determination unit.
It consists of a display section for displaying. a, b, c and d
The intensities I _a , I _b , I _c , and I _d of the directions can be represented by the product of the sound pressure P (t) and the particle velocity (t) of the opposing micro signals. Here, since the particle velocity (t) is proportional to the spatial gradient of the sound pressure of the two micro signals, the calculation shown in the following equation is realized by an electric circuit.

The present embodiment is configured as described above, and the sensors 11 and 12 that face each other and the sensor 1 that faces the sensors 11 and 12 in the direction of 45 degrees.
3 and 14, and sensors 15 and 16 that also face each other at 90 degrees
, And sensors 17 and 18 corresponding to 135 degrees are provided, and the magnitude and direction of the intensities in the directions of each pair obtained by using the sensor output signals of these four systems are combined to synthesize the sound wave propagation direction and measurement point. It is characterized by a configuration provided with a display section for indicating the absolute azimuth and the size thereof. Also,
It has the feature that it can be used as an analysis device that can calculate and display the intensity by inputting some electric signal when the sensor is removed. In this embodiment, the conventionally required sensor (microphone) rotation drive mechanism is not required, and the intensity, that is, the sound flow direction is known at a time, so the direction of the sound limit can be detected at any time. As a result, we have made it possible to perform highly accurate exploration of moving sound sources and sound sources whose loudness changes over time. If an analog filter such as a switch capacitance filter is used in the arithmetic unit, sound source search for each frequency band can be performed in real time. The microphone shown in the above embodiment is an electret-type condenser microphone, which does not require constant supply of a DC voltage and does not require a preamplifier for impedance conversion, but is miniaturized, but four pairs of microphones are orthogonal and crossed. Other models of microphones that can be configured as described above can achieve the same effects as the present invention. Furthermore, in the present 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 field-specific portable Wattometer, but from the outside. A configuration using a drivable power source is also included in the present invention.

〔The invention's effect〕

As described above, according to the intensity Wattometer of the present invention, the direction of sound and the absolute direction and magnitude (that is, vector) of the sound can be quantitatively grasped, so that the direction of the sound source can be immediately measured from this flow direction. Moreover, it can be detected in real time. Moreover, it is possible to detect a sound source whose size and position are changed with high accuracy. The operation unit in the configuration of the present invention has four times as many lines as the conventional method, but it is possible to reduce the size and power consumption due to the recent LSI integration technology and the like, which is remarkable as compared with a heavy weight meter. No increase in weight or significant size increase.

[Brief description of drawings]

FIG. 1 shows an intensity water meter 1 according to the present invention.
It is an external view of an Example. FIG. 2 is an external view showing a state in which the sensor unit is separated in the above embodiment. FIG. 3 is an enlarged view of the display unit housed in the box at hand in the above embodiment. FIG. 4 is a directional characteristic diagram of a pair of sensors, FIG. 5 is a directional characteristic diagram of four pairs of sensors, and FIG. 6 is a block diagram of an intensity calculation unit and a display unit for determining a sound incident direction. FIG. 7 is an analysis chart of directivity characteristics of a pair of sensors, FIG. 8 is a system diagram showing an example of calculation and display of the incident direction, and FIG. 9 is a chart showing a display area of the incident direction. 1 ... Sensor section, 2 ... Support, 2 '... Connector, 3 ... Display switching switch, 4 ... Display section, 5 ... Hand box section, 6 ... Communication cable, 7 ... Intensity arithmetic circuit section, 8 ... Power supply section, 9 ... Calculation part box part, 10 ... Electric signal, 11-18 ... Sensor, 19 ... Spacer, 20 ... Direction display LED, 21 ... Size display LED, 22 ... Absolute direction display LED, 23 ... Divider, 24 Comparator, 25 ... Angle equivalent voltage generating circuit, 26a to 26d ... Comparator, 27 ...
Memory, 28a, 28b ... Sign inverting circuit, 29 ... Sign determining circuit, 30 ... Sign determining circuit, 31 ... Decoder, 32 ...
Driver circuit, 33 ... Sign discriminating circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Shimoide 502 Jinritsucho, Tsuchiura City, Ibaraki Prefecture, Institute of Mechanical Research, Hiritsu Manufacturing Co., Ltd. (72) Ryoji Sato 502 Jinritsucho, Tsuchiura City, Ibaraki Prefecture (56) References Japanese Patent Laid-Open No. 61-256226 (JP, A)

Claims (9)

[Claims] 1. A sound comprising a sensor section for detecting the direction and magnitude of a sound wave, a calculation section for calculating sound intensity based on an output signal of the sensor section, and a display section for displaying the calculation result. In the intensity Wattometer, a pair of sensors are installed so as to face each other in a fixed direction, and a pair of sensors are provided along a plurality of directions intersecting at a fixed angle with respect to the fixed direction. An acoustic intensity Wattmeter, comprising: a display unit for inputting an output signal to a calculation unit and showing a direction and a magnitude of a sound intensity calculated by the calculation unit. 2. The fixed direction is a horizontal direction, and
The constant angles are 45 degrees, 90 degrees, and 135 degrees,
The sound intensity Wattmeter according to claim 1, wherein each of the plurality of directions is a horizontal direction. 3. The four pairs of sensors are provided with electrical contacts for switching the connection so that only the output signals of the one pair of the sensors are input to the arithmetic unit. The sound intensity Wattmeter according to the first item of the range. 4. The calculation unit has a function of analyzing and displaying the magnitude and direction of the sound intensity based on the electric signal output. The sound intensity Wattmeter according to the item. 5. The sound intensity wattmeter according to claim 1 or 2, wherein the sensor is an electret condenser microphone. 6. The acoustic device according to claim 1, wherein the arithmetic unit is mainly composed of an analog circuit. Intensity Wattmeter. 7. The sound intensity watt according to any one of claims 1 to 6, wherein the display unit has at least one of an LED and a liquid crystal. Meter. 8. The sound intensity watch according to claim 1 or 2, wherein the display unit has a switching device for one-dimensional sound source direction identification and a display function. Meter. 9. The sound intensity Wattmeter according to claim 1, wherein the sound intensity Wattmeter is fed by an internal power source. Sound Intensity Wattmeter.