JPH0894428A - Sound-level meter - Google Patents

Abstract

PURPOSE: To measure a sound environment by using an index which conforms to the sense of a human being by a method wherein a sound-level meter is constituted of a microphone for sound detection, a quiet-sound-degree detection circuit, a quiet- sounddegree indicator and the like. CONSTITUTION: In a quiet-sound-degree detection circuit 4, a sound detection signal S1 by a microphone 3 is attenuated and amplified by an attenuator and an amplifier for a preprocessing circuit 4A, a processing operation is executed to the signal S1 by using a sense-of-hearing correction circuit so that the signal is endowed with a frequency characteristic to the hearing characteristic of an ear, and a signal S2 is obtained. The signal S2 is rectified by an effective-value rectifying circuit 4B, it is converted into an effective-value DC output expressing the effective value of the signal S2, the signal is logarithmic-converted by a logarithmic conversion circuit 4C, and the signal S2 as a noise-level signal S4 expressing a noise level is sent out to a quiet-sound-degree indicator 5 from the output end of the circuit 4C. The indicator 5 indicates a numerical value which becomes small from 90 down to 10% when a sound environment becomes a minimum quietness level from a maximum quietness level, and an operator can easily read out the quietness degree of the sound environment intuitively on the basis of the numerical value of a quiet-sound degree.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silent meter, and is particularly suitable for application when evaluating the quietness of a sound environment.

[0002]

2. Description of the Related Art Conventionally, a sound level meter has been used as a measuring instrument when evaluating a sound environment. The sound level meter represents the noise generated from noise sources such as machines, factories, roads and aircrafts by the noise level [dB], and evaluates the degree to which a person feels noisy by the magnitude of the noise level. There is. A conventional sound level meter is considered to be effective as a measure for quantitatively grasping the degree of adverse effects on the human body, as one field of pollution problems.

[0003]

However, the sound environment not only has noise that adversely affects the human body, but also that quietness is an element that forms a sound environment that gives comfort to the human body, and the degree of quietness is intuitive. If it can be measured so that it can be grasped, it is considered to be effective as a means for adjusting the sound environment for the human body. The present invention has been made in view of the above points, and an object thereof is to propose a silent meter capable of measuring the quietness of a sound environment as a numerical value that allows a person to intuitively grasp.

[0004]

In order to solve such a problem, according to the present invention, a microphone means 3 for transmitting a sound detection signal S1 having a magnitude corresponding to the sound pressure of a sound environment sound and a sound detection signal S1 are provided. Sound environment sound noise level [dB] is 1 [d
B] When increasing, the quietness detecting means 4 for converting into a quietness [%] having a relation that the numerical value decreases by 1 [%] and the conversion output S4 of the quietness detecting means 4 are set to a quietness of 100 to 0 [%]. ] The display means 5 for displaying the numerical value of] is provided.

[0005]

[Function] By focusing on the quietness of the sound environment, the sound environment sound is measured by the quietness [%] such that the quieter the sound environment becomes, the larger the quietness becomes. It is possible to realize a silent meter that can evaluate the sound environment with a numerical value that matches the human sense.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

(1) Principle of Quietness Measurement Generally, the relationship between the noise level L _A and the noise energy I _A is expressed by the following equation.

[Equation 1] As described above, the noise level is expressed in the unit [dB] by the common logarithm of the noise energy I _A. Therefore (1)
From the equation, the noise energy I _A is

[Equation 2] , Is expressed by the number of watts per unit area.

In the relationship of the expressions (1) and (2), the maximum audible value L _AMAX when a person listens to noise is L _AMAX = 120
[DB] and set the minimum audible value L _AMIN to L _AMIN = 20
[DB] as the maximum audible value L _AMAX to the minimum audible value L _AMIN
Assuming that the noise levels up to 10 dB are graduated in increments of 10 [dB], as shown in FIG. 1, each noise level L _A = 120,110
, 100 …… The noise energy I _A at 20 [dB] is I _A
= 10 ⁰ , 10 ^-1 , 10 ^-2 ...... 10 ^-10 [W / m ² ].

In FIG. 1, noise energy I _A [W
Focusing on the absolute value EX of the exponent of / m ² ], the absolute value EX of the exponent is graduated by an array such as EX = 0, 1, 2 ...

The change in the magnitude of the absolute value EX of this index, that is, EX = 0, 1, 2, ... 10 corresponds to the reciprocal of the magnitude of the energy of noise in consideration of the human sense of sound. , The absolute value EX of the index is EX = 0, 1, 2
The noise energy I _A is I _A = 10 ⁰ , 10 ⁻¹ , 10 ⁻² …… 10 as it increases by 1 like 10
^The noise level L _A is L _A = 120, 110, 100 ...... while decreasing in 10 ^-1 increments like ^-10 [W / m ² ].
Go down in steps of 10 [dB], such as 20 [dB].

The noise level L _A and the noise energy I
Quietness Q based on the relationship between _A and the absolute value EX of the index
[%] Is a unit of 10 times the absolute value EX of the index [%]
By expressing by, Q = 0, 10, 20 …… 100 [%] is established.

Thus, the quietness Q [%] is Q = 100
When [%], noise level L _A and noise energy I
_A represents the smallest state, and accordingly represents a quiet and soundless sound environment, while the noise level L _A and the noise energy I _A are the largest when the quietness Q is Q = 0 [%], This represents the loudest sound environment. And quietness Q
Is decreased by 1 [%] from Q = 100 [%] to Q = 0 [%], this means that the sound environment is quiet and there is no sound (noise level L _A = 20 [dB]). ), The sound gradually increases (that is, the noise level L _A is 1 [d
B), which means that the situation is gradually increasing.

Thus, the degree of quietness of the sound environment depends on the quietness Q.
When the value of [%] is 100 to 0, it is possible to intuitively grasp the level of a sound environment with a high degree of silence as a value of the high degree of silence Q, while the degree of quietness decreases. It can be intuitively recognized as the value of the quietness Q that reduces the quietness of the sound environment.

[2] First Embodiment In FIG. 2, reference numeral 1 denotes a silent meter as a whole, and a case 2
Based on the sound environment sound collected by the microphone 3 mounted on the tip of the sound level, the sound level of the sound environment sound is detected by the sound level detection circuit 4 shown in FIG.
Displayed above.

In the case of this embodiment, the quietness indicator 5 has a two-step scale of quietness from quietness Q = 90 [%] to Q = 10 [%] according to the switching operation of the quietness switching switch 6. It can be displayed by indicating 90 to 50 and 50 to 10 with the pointer 7. In the case of this embodiment, the quietness detection circuit 4 attenuates and amplifies the sound detection signal S1 obtained from the microphone 3 in the preprocessing circuit 4A by using the attenuator and the amplifier, and detects the sound by using the auditory sense correction circuit. The signal S1 is processed so as to have a frequency characteristic that matches the listening characteristic of the ear, and thus the preprocessing circuit 4
A sound input signal S2, which is an AC signal of a predetermined magnitude, is obtained from A.

The sound input signal S2 is converted into an effective value DC output that represents the actual value of the sound input signal S2 by being rectified in the effective value rectifying circuit 4B, which is a logarithmic conversion circuit 4C.
Is logarithmically converted at. Thus, at the output end of the logarithmic conversion circuit 4C, the sound input signal S2 is sent to the noise level L _A (FIG. 1).
Is transmitted from the silence level detection circuit 4 to the silence level indicator 5.

When the quietness indicator 5 changes so that the sound pressure of the environmental sound collected by the microphone 3 increases, the display operation is such that the pointer 7 is shaken at the shake position logarithmically converted. do. Thus, while the pointer 7 swings so as to change logarithmically, when the pointer 7 comes to the display position of the noise level L _A = 20 to 120 [dB] in FIG. = 100 to 0 [%] is engraved, and thus the noise level of the sound environment sound collected by the microphone 3 is converted into the quietness Q and the quietness indicator 5
Displayed above.

The preprocessing circuit 4A is provided with a quietness range switching switch 4D. The quietness range switching switch 4D is provided.
When D is switched to the quiet side contact L side, the sound detection signal S1 is set to the quiet scale 90 to 50 of the quietness indicator 5.
Is applied to the sound detection signal S1 so that the degree of silence can be displayed. Along with this, when the quietness range switching switch 4D is switched to the quietness side contact S side, an attenuation amount in a range such that the sound detection signal S1 can be displayed using the scales 50 to 10 of the quietness indicator 5 is set. Sound detection signal S1
Is designed to give to.

Thus, when a quietness of 90 to 10% is indicated on the quietness indicator 5, the quietness can be adjusted with high accuracy by using the range of 90 to 50 or 50 to 10 which is doubled. It is designed to give instructions.

In the above configuration, when the operator turns on the power switch 10 (FIG. 2) to supply power to the quietness detection circuit 4, the sound environmental sound collected by the microphone 3 is generated. By supplying the sound detection signal S1 of the signal level corresponding to the sound pressure to the preprocessing circuit 4A of the silence level detection circuit 4, the silence level range switching switch 4D.
The sound input signal S2 attenuated by the amount of attenuation corresponding to the switching position is applied to the effective value rectifier circuit 4B, and the effective value DC output S obtained by being rectified by the effective value rectifier circuit 4B.
3 is subjected to logarithmic conversion processing in the logarithmic conversion circuit 4C and given to the quietness indicator 5 as a quietness detection signal S4.

At this time, the pointer 7 of the quietness indicator 5 swings to the swing position of the silentness of 90 [%] in a state where there is almost no sound in the sound environment, whereas the silent environment becomes noisy. As the noise level increases by 1 [dB] as it goes, the pointer 7 sways to the graduation position, which decreases by 1 [%], and when the sound environment becomes the maximum noise level (noise level). When L _A reaches L _A = 110 [dB]), the silentness indicator 5 swings to a position indicating the minimum silentness 10 [%].

Thus, the quietness indicator 5 changes from a state in which the sound environment is in the maximum quietness (no noise) to a state in which the quietness is gradually reduced to the minimum quietness (noise is maximum). If the quietness is reduced in the process of reaching
It is possible to make a display that decreases from [%] to 10 [%], which allows the operator to intuitively determine the degree of quietness of the sound environment from the magnitude of the quietness value. Can be easily read from.

Further, in the case of this embodiment, a range having a high degree of silence, that is, a scale having a degree of silence of 90 to 50%, and a range having a low degree of silence, that is, a scale displaying a degree of silence of 50 to 10% are displayed. Since the and can be switched by using the quietness range switching switch 6, the accuracy of the quietness that can be read by the operator can be further improved. The preprocessing circuit 4A shown in FIG. 3 can have the configuration shown in FIG.

Sound detection signal S obtained from the microphone 3
1 is input to the auditory sense correction circuit 4A3 through the attenuator 4A1 and the amplifier 4A2, and its output is sent out as a sound input signal S2 through the attenuator 4A4 and the amplifier 4A5. The attenuators 4A1 and 4A4 are adapted to switch the amount of attenuation given to the sound input signal S2 while interlocking with the output of the quietness range switching switch 4D, and thus the quietness range switching switch 4D is moved to the quietness side contact L side. With respect to the attenuation amount when switched, the attenuation amount is increased by 40 [dB] when switched to the low-silence-side contact S, so that the scale of 90 to 50 [%] in the silence indicator 5 is increased. It can be displayed by the same pointer 7 as the display and the display of the quietness of 50 to 10 [%].

The amplifiers 4A2 and 4A5 are provided with a sound input signal S2.
As a sound detection signal with an amplification degree that sets the signal level of the silence level detection signal S4 given to the silence level indicator 5 via the circuit in the subsequent stage, that is, the effective value rectification circuit 4B and the logarithmic conversion circuit 4C, to an appropriate value. Amplify S1.

The hearing sound correction circuit 4A3 adds the hearing characteristic of the human ear to the sound input signal S2 in consideration of the fact that the human ear has the auditory characteristic with respect to the frequency component of the sound detection signal S1. Frequency correction operation is performed. The environmental standards are
As shown in FIG. 5, the noise level is stipulated, but if this is expressed in terms of quietness, it is prescribed that the quietness of a certain level or higher be maintained for each type and area of each area. Therefore, it becomes possible to intuitively understand the degree of the sound environment defined by the environmental standard to be observed.

In order to examine what range of sound environment can comply with such environmental standards, experiments were carried out, and as shown in FIG. 6, the quietness [%] under each sound environment could be obtained. According to Fig. 6, from the "quiet house night" where it is considered that people are quiet in the experience, to the "immediately below the plane taking off and landing", which is the limit of the noise, the sound environment that most people experience It can be seen that the quality of can be presented as a numerical value that can be accurately and easily grasped by the value of the silentness [%].

[3] Other Embodiments (1) In the quietness indicator 5 of FIG. 2, the quietness is switched between two ranges, that is, 90 to 50% and 50 to 10%. Although the case where the display is made possible by performing the above is described, the display may be made by one scale without changing the range.

(2) In the quietness indicator 5 of FIG. 2, only the quietness [%] is displayed as the scale 8. Instead of this, as shown in FIG. 7, one scale 8 is used. The silent level [%] (100 to 0 [%]) may be displayed simultaneously with the corresponding noise level [dB] (20 to 120 [dB]). Thus, it is possible to realize a silent meter that can easily check the noise level in the quietness of the sound environment to be measured each time.

(3) In the above embodiment, the case where the noise level of 120 to 20 [dB] is displayed as the noise level of 100 to 0 [%] has been described, but the correspondence with the noise level is as follows. Not limited to, for example, 100 to 0 [dB], 110 to
It may be adapted to various ranges such as changing to 10 [dB], 130 to 30 [dB], 140 to 40 [dB].

(4) In the quietness indicator 5 shown in FIG.
Although the case of analog display using the pointer 7 has been described, the same effect as in the above case can be obtained by using digital display by numerical values instead.

(5) In the above embodiment, the scale of the quietness indicator 5 is marked as a change in the noise level [dB], but it may be marked at equal intervals instead.

[0033]

As described above, according to the present invention, the sound environment sound is displayed according to the degree of silence based on its quietness, so that the sound environment sound can be adapted to the human sense of the sound environment. It is possible to provide a measuring means capable of intuitively determining the quality of the sound environment by using such an index.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of a silent meter according to the present invention.

FIG. 2 is a front view showing an embodiment of a silent meter according to the present invention.

FIG. 3 is a block diagram showing a silentness detection circuit.

FIG. 4 is a block diagram showing the preprocessing circuit of FIG.

FIG. 5 is a diagram showing environmental standards in terms of silence.

FIG. 6 is a chart showing experimental results.

FIG. 7 is a front view showing another embodiment of the silent meter.

[Explanation of symbols]

1 ... Quiet meter, 2 ... Case, 3 ... Microphone, 4
...... Quietness detection circuit, 5 ...... Quietness indicator, 6 ...... Quietness range switching switch, 7 ...... pointer, 8 …… scale, 10
...... Power switch.

Claims (3)

[Claims] 1. A microphone means for transmitting a sound detection signal having a magnitude corresponding to the sound pressure of the sound environment sound, and the noise level [dB] of the sound environment sound is increased by 1 [dB] in the sound detection signal. At this time, the quietness detecting means for converting the quietness [%] having a relation that the numerical value decreases by 1 [%], and the converted output of the quietness detecting means,
A silent meter, comprising: a display unit for displaying a numerical value of [%]. 2. An attenuating means for attenuating the sound detection signal by a predetermined amount of attenuation so that the quietness of 100% to 0% in the displaying means is divided into a plurality of ranges and displayed. The silent meter according to claim 1, further comprising: 3. The display means displays a quietness [%],
The silence meter according to claim 1, further comprising a display of a noise level [dB] corresponding to the degree of silence [%].