JPS59143925A - Noise detecting device - Google Patents

Abstract

PURPOSE:To detect the noises of a material to be detected accurately, by arranging a plurality of microphones on the vertical line from the material to be measured with the microphone being shifted each other, and detecting the noises of the material to be detected. CONSTITUTION:A material to be detected is mounted on a table 7 and placed on a floor 8. A pair of microphones 2 and 3 are closely arranged on the vertical line from a material to be detected 1, with the microphones being shifted each other by DELTAl. In this contitution, since the positions of the pair of the microphones 2 and 3 are shifted by DELTAl with respect to the material to be detected 1, a time difference or a phase difference occurs in the waveforms of the noises, which are emitted from the material to be detected 1 to the microphones 2 and 3, as in the conventional case. With respect to the external noises, which enters the microphones 2 and 3 from all horizontal directions, the time difference or phase difference are hard to occur. Even though the difference occurs, the values of the noises are small. A signal processor 6 finds only the noises, which yield the time difference or phase difference, removes the dark noises, and detects only the noises from the material to be detected 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a noise detection device that appropriately measures the noise of an object to be detected by using a plurality of microphones under conditions of loud dark noise.

As a conventional ridge noise detection device 4, there is one shown in FIGS. 1 and 2. That is, in Figures 1 and 2, (1) is the object to be detected whose noise is to be detected, such as a motor installed horizontally on the floor, and (2) the noise of the G-1 object to be detected 11). The front microphone to be detected (8) is placed backward from the position of the front microphone (2) with respect to the object to be detected (1) by Δl, and the rear microphone (4) has the same characteristics and sensitivity as the front microphone. 5) is an amplifier that amplifies the output signal of each microphone (2) +8), and (6) is a signal processing device into which the signals from the amplifiers (4) and (5) are introduced.

In this conventional one, static sound is converted into compression waves in the air? The noise emitted from the detected object (1) is transmitted through the microphone (2) parallel to the right side of the detected object (1) in the figure.
) (8) is reached. For this reason, the microphone (2) (
Although the magnitudes of the outputs of microphones (2) and (3) are slightly different, there is also a time difference commensurate with the deviation of Δl between the output signals of both microphones (2) and (2).

However, in the longitudinal direction of microphone (2) +8),
When noise from the right angle and horizontal direction or from above is detected by the microphone (2) 18), the time difference between the detection signals from one side to the other is not very large. In particular, noise generated manually from a direction perpendicular to a straight line connecting the centers of the tips of the microphones (2) and (3) has the same waveform with no time lag.

In signal processing H (a), the time difference between the output signals is regarded as a phase shift of the alternating current signal, and a system of 7X-ware and software is incorporated rather than only detecting human noise with a large phase difference. However, microphone (2) +
When 8) is installed as shown in Figure 1, the signal processing device (6)
In this case, since there is a phase difference in the output signal of the microphone (2) 1.11 due to the noise from the back of the microphone (2) [11], it is difficult to distinguish it from the noise generated from the object to be detected (1). Become. Roughly speaking, if the detected object (1) is large, the external noise incident from a far left direction in Fig. 1 will be shielded by the detected object (1) and there will be little problem. When 1) becomes smaller, it becomes a microphone (2)
+8), external noise enters from the same direction as the detected object (1), making it difficult to distinguish it from the noise of the detected object (1).

Microphone (2) +81 installation method and 17, second
Attempts have also been made to consider a method of arranging the objects on the same plane as shown in the figure, but these problems cannot be improved at all.

As described above, the conventional microphone installation method has the disadvantage that it is easily influenced by this undesirable background noise. The present invention has been made in order to eliminate the drawbacks of the conventional devices, and it is an object of the present invention to provide a noise detection device W: which is less susceptible to the influence of background noise.

An embodiment of the present invention will be described below with reference to FIG. That is, in Fig. 8, ]1) is an object to be detected, which is smaller than those shown in Figs. 1 and 2, and is placed on the floor (8) instead of being mounted on a stand (7). . (2) [8] is a pair of microphones arranged close to each other on the vertical line of the object to be detected (1) and shifted by Δl from each other.

With this configuration, the noise emitted from the detected object (1) is generated because the position of the pair of microphones (2)'+3) is shifted by Δl with respect to the detected object (1). Microphone (2) [11
) A time difference or phase difference occurs in the noise waveforms generated manually.

However, microphone (2) (
8) With respect to external noise caused by human input, a time difference or a phase difference is unlikely to occur, or even if it does occur, the value will be small. Therefore, the signal processing device (6) that detects only the noise with a time difference or phase difference removes the background noise and detects only the noise of the detected object (1).

However, as shown in Figure 3, microphones (2) (3)
), the microphone (2) +
8) The position is different. Therefore, as shown in Figure 4, place the microphone (2) +3) on the vertical line passing through the object to be detected (1).
If the end faces i of 2 and 3 are aligned, there will be no difference in horizontal position, background noise will be removed more efficiently than in the case of FIG. 3, and only the noise of the object to be detected (1) can be detected. Note that microphone (3) is hidden behind microphone (2).
There was a concern that it would be difficult to detect the noise of the object to be detected 11), but it was actually tested! As a result, 5KH
Below z, there was no difference in the output signal of the microphone (2) l11).

In addition, in the one in Figure 4, the microphone (2) [8] is facing the left side of the figure, so the dark i
This may give the illusion that the strong sound components are getting louder, but since microphones have omnidirectional characteristics, there is little external influence.

Roughly speaking, instead of the one shown in Fig. 4, the microphone (2) 13) is arranged facing each other and aligned with the tip on the vertical line passing through the object to be detected, as shown in Fig. 5. Noise from the object to be detected (1) can be detected accurately without being hidden behind the side microphone (2).

Based on the above, the sound detection device according to the present invention detects the noise of the detected object by arranging a plurality of microphones vertically 11iIll1 to the detected object and staggered from each other. It is possible to detect the noise of the target object in an appropriate manner.

[Brief explanation of drawings]

1 and 2 are schematic configuration diagrams showing a conventional noise detection device of this type, FIG. 3 is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 4 and 51\IC'i of this invention. FIG. 3 is a schematic configuration diagram showing another implementation. In the figure, (1) is an object to be detected, (2) 131 is a microphone, (4), (5) is an increase rlJ'#r%, and (6) is a signal processing device. In addition, the same reference numerals in the figures indicate the same - or the equivalent Ee+ (minute. Agent Makoto Katsurachi - Figure 3 σ Figure 4 Figure 5 Procedural amendment (voluntary) Mr. Commissioner of the Japan Patent Office 1, Indication of case Patent application No. 58-17684 2. Name of the invention: Noise detection device; 3. Relationship with the case of the person making the amendment Patent applicant address: Chiyo, Tokyo]] 2-3 Sara-chome, Marunouchi-ku, Tokyo
Name (60),) Mitsubishi Electric Corporation Representative Ministry Katayama Hitoshi Hachibe 4, Agent address Chiyo, Tokyo + ■] 2-3 Sara-chome, Marunouchi Ward, Tokyo
Claims of the specification subject to amendment No. 5 (6. Contents of the amendment as per the attached sheet Claims Fl) A plurality of microphones are shifted from each other in a linear direction on the vertical line of the object to be detected. A noise detection device characterized in that the device is adapted to detect the noise of the object to be detected. (2) The noise detection device according to claim 1, wherein the plurality of microphones are arranged close to each other.

Claims (1)

[Claims] (i) A plurality of microphones are arranged on a vertical line of the object to be detected so as to be shifted from each other in the entire straight line direction;
A noise detection device characterized in that it detects a t-sound. (2) The noise detection device according to claim 1, wherein the plurality of microphones are arranged close to each other. (8) The noise detection device according to item 1 of the scope of patent HvJ, wherein the plurality of microphones are arranged to be isolated from each other.