JPS63169524A - Acoustic intensity wattmeter - Google Patents

Abstract

PURPOSE:To facilitate sound source survey, to improve measurement efficiency, and to take an accurate measurement by displaying the values and directions of acoustic intensity in plural frequency bands at the same time. CONSTITUTION:A couple of sensors 1 and 2 are provided and a couple of sensors 3 and 4 are further provided at right angles to a prolongation direction connecting the sensing part of the sensors 1 and 2 so as to detect the direction of a sound source in two dimensions. Further, plural filters are installed so as to classify the output signals of the sensors 1-4 by the optional frequency bands, and an arithmetic part 10 is provided which processes the output signals of the respective bands from the filters; and two couples of arithmetic output results of those frequency bands are combined and the propagation directions and levels of acoustic waves in the frequency bands are displayed 6 at the same time. Consequently, the sound source azimuth directions and the values of intensity in the plural frequency bands can be measured at the same time; and the sound source survey is facilitated, the measurement efficiency is improved, and the more accurate measurement is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an acoustic intensity wattmeter having a sensor section, a filter section, an intensity calculation section, and a display section. This invention relates to a sound intensity wattmeter that simultaneously displays its direction.

[Conventional technology]

High-accuracy detection technology for noise sources is essential to implement noise countermeasures for equipment quickly and economically, and acoustic intensity wattmeters have recently been attracting attention as a measuring device for this purpose. Conventionally, this type of wattmeter consists of a pair of sonic sensor sections arranged opposite to each other, a support section for these sections, an intensity calculation section, and a display section that shows the magnitude and direction of the resulting intensity. Are known.

In other words, the University of Tokyo Institute of Industrial Science production leaflet N
It is discussed in the document entitled "Simple Acoustic Intensity Meter", 124. There are also examples of acoustic intensity wattmeters being commercialized and sold, but the acoustic wave sensor section is composed of only a pair of sensors. Therefore, when displaying the direction of the sound source (sound source search), it is necessary to press the vicinity of the sound source in detail because it is only indicated by positive (+) and negative (-). Furthermore, conventional commercially available acoustic intensity wattmeters were stationary types suitable for measurements in laboratories and laboratories.

In 1982, Pruel Kjaer (Denmark) released a portable sound intensity wattmeter. however,
This portable intensity wattmeter only has a pair of sensors, and does not have the ability to simultaneously measure and display the magnitude or direction of intensity in multiple frequency bands, so analysis of each frequency is not possible. It was difficult to deal with fluctuating noise.

[Problem that the invention seeks to solve]

The above conventional technology basically measures the magnitude and direction 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 sensor is moved 180 degrees around the center of the pair of sensors. @Needs to be rotated. In this case, the magnitude of the intensity for each sensor must be memorized and the direction of the sound source position must be determined, and the target is equipment where the noise level and sound source position change over time. In this case, the method of displaying the direction of the sound source position using a pair of sensors has the problem that it cannot be applied or that the accuracy deteriorates significantly even if it is applied. Since it is determined based on the display, measurements at several points are required to determine the location of the sound source. Moreover, since it does not have a function to simultaneously display the magnitude and direction of the intensity level in each frequency band, measurements in the required frequency band must be repeatedly performed at the same point, which causes the above problems. Similarly, when the noise level and sound source position change over time,
This made it impossible to apply the method, and there were also problems in terms of efficiency.

The purpose of the present invention is to simultaneously display the magnitude of sound intensity in multiple frequency bands and its direction, thereby facilitating sound source location, improving measurement efficiency, and enabling more accurate sound measurement. Our purpose is to provide an intensity wattmeter.

[Means for solving problems]

゛ A pair of sensors is further installed perpendicular to the extension direction connecting the sensing parts of this sensor, and multiple filters are installed to divide the output signal from each sensor into arbitrary frequency bands. Calculate the output signal at each frequency (magnitude).

The structure has a mechanism that combines the two pairs of calculation output results for each frequency band and simultaneously displays the propagation direction and magnitude of the sound wave in each frequency band.

[Effect]

When detecting the position of a sound source, the propagation direction of the sound wave is determined by calculating the intensity of the signals collected by two pairs of sensors.
It is calculated based on the magnitude ratio, sign, and magnitude relationship of these output signals, and by inputting the output signals from these two pairs of sensors to multiple filters and corresponding calculation units, multiple It is now possible to simultaneously measure the direction of the sound source position and the magnitude of the intensity in the frequency bands - the calculation results (magnitude, magnitude,
By providing a mechanism that simultaneously displays directions, it is possible to grasp the sound source or the characteristics of the sound in the sound field at a glance.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. FIG. 1 shows a perspective view of an intensity wattmeter. The wattmeter includes sensors 1 to 4, a support part 5 that supports the sensors, one end of the support part 5,
It is composed of a hand box part 7 having a display part 6, a calculation box part 10 for accommodating an intensity calculation circuit part 8 and a power supply part 9, and a communication cable 11 between the hand box part 7 and the calculation box part 10. . FIG. 2 shows the configuration of the sensor section. Sensors 1 and 2 are oriented in the axial direction
It is a sensor for measuring the intensity of components, and sensor 3,
4 is a sensor for measuring the intensity of the Y component in the direction perpendicular to the axis of the support portion 5. Sensor 1, 2 and sensor 3,
Sensors 1 to 4 are small electret microphones.

The figure shows an intensity calculation block and a display pull diagram in one frequency band. The outputs A, A of the sensor 1.2 and the outputs B, B of the other pair of sensors 3, 4 are connected to the byte-pass filters 12, 13. 14.15, low-pass filters 16, 17, 18° 19, and a phase adjustment circuit 20 to output signals in an arbitrary frequency band, amplify them, and pass them through a buffer section 22 for impedance matching. , intensity component calculation circuit 23
Intensity components X and Y in the X and Y directions are calculated. A multiplication unit 24 that calculates the magnitude and direction from these values X and Y
, the size of the divider 25 and the logarithmic converter 26.
The direction calculation circuit 27 performs calculations, and the results are displayed on the size display section 28 and direction display section 29. The intensities IX and IY in the X and Y directions are expressed by the product of the sound pressure p (t) of the opposing sensor signal and the particle velocity V (t), respectively.The calculations shown in the following equations are realized using an electric circuit.
2, where e is the density of air, Δrt and Δrz are the distances between each pair of sensors, and P1 to P4 are the output sound pressures of sensors 1 to 4. If the incident angle of the sound wave is α, the intensity of the X-axis and Y# components LX, IY are as follows.

Ix= l I l 1Icosa, Iv= l Iy
l @5ina, so the magnitude II+ is and the angle α is.

tanα=　l　Iy/Ixl or cotα=　l　work x／　IY　1 is determined from the sign relationship between Ix and IY.

FIG. 4 is a block diagram showing an embodiment of a calculation unit for determining the direction of incidence of sound. In this embodiment, the entire circumference is divided into 36 parts at 10° pitches for calculation and display. Signal II after intensity calculation collected by two pairs of sensors
The arithmetic unit 30 divides xl and IIyl. In this case, the calculation is performed based on the determination result of IIY/IXI obtained by the comparator 31 and indicating the magnitude of 1Ixl and 1Iyl.

Comparator 3 compares this value with the output value of angle equivalent voltage generation circuit 32.
3 to 36, this digital signal 4 bits
is input into the memory 37 as . On the other hand, O≦lIy/Ix
Since the display area in the direction corresponding to l≦1 or 0≦IIX/IYI≦1 is divided into 360° in all directions, the comparator 3 is used to specify a certain area from among these areas.
1. Sign inversion circuit 38, 39, sign discrimination circuit 40, 41
, 42.degree. 43, the signals are digitally converted into signals representing the respective codes of Ix, -Ix, IY, and -IY and the magnitudes of Ix and Iv. When these signals and a 4-bit signal are input to the memory 37 as an address, a binary signal (6-bit
) is output.The decoder 44 and driver circuit 45 in the block diagram are a circuit for converting a binary number into at least a 36-decimal number and a circuit for driving an LED in a direction corresponding to this output. FIG. 5 shows an example of a configuration for simultaneously measuring, calculating, and displaying the magnitude of intensities in multiple frequency bands and their directions, and shows a sensor section 46 and a microcontroller consisting of two pairs of sensors and their amplifiers. The output signal from the amplifier section 47 is inputted to a plurality of filter/buffer sections and arithmetic circuit sections 48 to 55. Each filter/buffer section and arithmetic circuit section include a filter section 21 shown in FIG. 3, a buffer section for amplification and impedance matching,
Intensity component calculation circuit, multiplier 24, calculation unit 2
The intensity component is divided by a filter provided in the fifth buffer section and the arithmetic circuit section as a signal of only an arbitrary frequency band, and the magnitude and direction of the intensity in each frequency band are obtained. The magnitude of the intensity in each frequency band obtained in this way is logarithmically converted by logarithmic converters 26.56 to 62, and is inputted to the vector calculation display control section 63 together with an output signal indicating the direction, and is displayed on the LED display. The magnitude and direction of intensity for each frequency are displayed in section 64. The present invention also includes a function of synthesizing (calculating) the intensities in each frequency band obtained in this way, and a function of displaying the synthesized value (all basses). Filter/buffer section and arithmetic circuit section 48 to 5 shown in FIG.
5 and the number of logarithmic converters 26, 56 to 62 installed are not limited to these, and even in the case of other numbers of installations, the present invention shows one embodiment of the display unit that displays the direction. In this embodiment, a frequency-specific direction display section 651 is provided on the hand box section 7 connected to the support section 5 that supports the sensor section.
Frequency size display section 66, A.

P, (all bus) display section 67, and microamp gain changeover switch 68. The 0-frequency direction display section 65, which is an embodiment including a buffer amplifier gain changeover switch 69, has L on a concentric circle to indicate the direction of sound flow.
A plurality of ED70s are arranged. LE on one concentric circle
When displaying the intensity direction in one frequency band and displaying the directions in a plurality of frequency bands using D, similarly, concentric circles of LED arrays corresponding to the number of frequency bands are provided. In this example, 63 to 8
Although an example of displaying an octave frequency band of kHz is shown, the present invention is not limited to this, and the present invention also includes cases where an arbitrary frequency band and an arbitrary number of bands are displayed. The frequency-specific size display section 66 includes a plurality of intensities 71 in a plurality of frequency bands arranged so as to display the intensity size for each of the plurality of frequency bands.
In this example, the horizontal axis represents the frequency, the vertical axis represents the size, and L
In this example, the size of each frequency and the composite value of the size at each frequency, A, P (all bass) are displayed by ED.The frequency band to be displayed, the display interval of the number and size, and the upper and lower limits. The value is not limited to this, and other frequency band number and size display ranges are also included in the present invention. In addition, this display section is also provided with an A, P, (all bass) display section 67 that displays the composite value of magnitudes in multiple frequency bands using LEDs, but this is also limited to A, P, and so on. The present invention also includes the case where the magnitude in other frequency bands is displayed.In addition, the microphone amplifier gain changeover switch 68 and buffer amplifier gain changeover switch 69 are included in the present invention to appropriately display the magnitude of the intensity. Although ¥1 is placed in the box 7, the installation location is not limited to the local box 7, and the present invention also includes installation in other locations.

According to FIG. 5 of the present invention, the magnitude of intensity in multiple frequency bands and its direction are displayed simultaneously.1 For example, in the case of an LED display as shown in FIG. , you can see at a glance that there is a sound source that generates high-frequency sound in the direction of the sensor (support direction), and that there is a sound source in the low-frequency range (63° 125 m) on the opposite side of the sensor.
It can be seen that the magnitude is high in the 500 to 2000 Hz range and small in the low frequency range (63,125 Hz), which is 5 anti-sensors, so that the sound source can be searched efficiently.

Furthermore, since the size and direction in multiple frequency bands can be displayed simultaneously, it is possible to deal with noise that changes over time, improving accuracy and reliability. In addition, when displaying the magnitude and direction in multiple frequency bands, it is not limited to displaying the magnitude and direction together, but only the magnitude in multiple frequency bands or only the direction. These cases are also included in the present invention.

〔Effect of the invention〕

According to the present invention, the magnitude and direction of intensity in multiple frequency bands can be grasped with the -eye, the efficiency of sound source detection is improved, and measurements are repeated for each frequency even for noise that changes over time. There's no need.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an intensity wattmeter according to an embodiment of the present invention, FIG. 2 is a configuration diagram of a sensor section, FIG. 3 is an intensity block diagram, and FIG. 4 is a block diagram of a calculation section.
FIG. 5 is a configuration diagram of the intensity, and FIG. 6 is an explanatory diagram of the intensity display section. Figure 1 Gi 2 Calculation 3 Figure 1, page continuation ■ Inventor New - [F] Inventor Sato Ryoho 50 Kandate-cho, Tsuchiura City, Ibaraki Prefecture Hitachi Machinery Research Laboratory Kandatsu, Tsuchiura City, Ibaraki Prefecture Town 50 Akiji Hitachi, Ltd. Mechanical Research Laboratory

Claims (1)

[Scope of Claims] 1. In an acoustic intensity wattmeter comprising a sound wave sensor section, an acoustic intensity calculation section, and a result display section, a pair of first sensors and a first A second pair of sensors is further provided so as to pass through the center of the sensor, and from the calculation results of the magnitude and direction of the intensity obtained using the output signals of each pair of sensors,
An acoustic intensity wattmeter comprising a display section that displays the magnitude and direction of the intensity. 2. A mechanism is provided for simultaneously analyzing and displaying the magnitude and direction of the intensity in a plurality of frequency bands by calculating the output signals of the respective pairs of sensors through a plurality of filters. A sound intensity wattmeter according to claim 1. 3. The device according to claim 2, further comprising a function of combining the intensities in the plurality of frequency bands and calculating an all-pass, and a function of displaying the combined value. Sound intensity wattmeter.