JPS624646B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an environmental noise measuring device for more accurately measuring the substance of working environment noise.

Conventionally, when workers work continuously in environments with high noise levels for long periods of time, there is a risk of hearing loss. In addition, in parallel with these countermeasures, measures were also taken to measure and manage the amount of noise each worker was exposed to. A noise meter was used as a device for this purpose. An example of a noise meter is explained according to FIG. 1. The signal received from the microphone 1 is as follows.
The A-characteristic amplifier 2 performs human sensory correction (A-characteristic) and amplifies the frequency, the squaring circuit 3 calculates the square of the input waveform, the voltage-frequency conversion circuit 4 converts the output voltage into a frequency, and the counter 5 The integrated count is digitally displayed on the display unit 6 as the noise exposure amount. In the above-mentioned noise meter, the measurement main body is stored and held in the worker's own body, specifically in the pocket of the worker's clothes, and the microphone needs to be placed near the ear, for example in the lapel of the worker's clothes. It was attached to etc. When measuring the noise exposure of an individual worker under such conditions, the sound generated by the worker wearing the noise meter will be heard along with the noise that should be measured from the noise source such as the machine. When a mixture of sounds is measured and the sound generated by the worker himself affects the measured value of noise exposure, there is a problem in that it is not possible to accurately grasp the actual nature of the work environment noise.

The present invention eliminates the above-mentioned problem.The noise exposure meter is equipped with a voice detection section, and when the voice influences the measurement of the noise exposure amount, the measurement is interrupted during the period of influence. To provide an environmental noise measuring device capable of accurately measuring the substance of environmental noise.

An embodiment of the present invention will be described below with reference to the drawings. In FIG.
4. A voltage frequency conversion circuit 14 for a noise exposure section, which is formed by sequentially connecting a counter 15 and a display section 16.
A gate circuit 17 is provided between the counter 15 and a small capacitor microphone 18 for detecting sound, an amplifier 19, a rectifier circuit 20, and a value at which the sound pressure of the sound affects noise measurement (for example, 80 dB).
It is equipped with a voice detection section formed by sequentially connecting comparison circuits 21 that are set to operate when the above occurs,
This configuration has a comparison circuit 21 connected to a gate circuit 17. When using the above device, the main body of the environmental noise measuring device is stored and held in the pocket of the worker's own work clothes, and the microphone 11 is attached near the ear, for example, on the collar. On the other hand, the small condenser microphone 18 must be attached to the part where the worker's own voice is to be detected, but in consideration of workability and the like, it is attached directly to the mastoid process where the voice signal in the oral cavity is detected as vibration. The purpose of attaching it directly to the skin is to prevent external noise from entering.

Next, to explain the operation, microphone 1
The noise signal received from 1 is sent to an A-characteristic amplifier 12.
The squaring circuit 13 calculates the square of the input waveform, converts the output voltage into a frequency, that is, a pulse train, and the gate circuit 17. Thereafter, the amount of noise counted and integrated by the counter 15 is digitally displayed on the display section 16 as the amount of noise exposure.
On the other hand, the voice generated by the worker himself is detected by a small condenser microphone 18, and its output voltage is amplified by an amplifier 19, rectified by a rectifier circuit 20, and converted into direct current. At this time, when the sound pressure of the worker's own voice exceeds a value that affects noise measurement, the comparator circuit 21 reverses and closes the gate circuit 17, and the voltage frequency conversion circuit 14 counts the frequency, that is, the electrical signal converted into a pulse train. Try not to.

As described above, when measuring a work environment, the present invention can detect sounds that may affect the noise measurement of the worker wearing the environmental noise measurement device.
Since the signals are not counted during the time when the noise occurs, the actual noise level can be accurately grasped, which has a great practical effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional noise level meter, and FIG. 2 is a block diagram of an embodiment of the present invention. 11: Microphone, 12: A characteristic amplifier circuit,
13: Square circuit, 14: Voltage frequency conversion circuit, 1
5: Counter, 16: Display section, 17: Gate circuit, 18: Small microphone, 19: Amplifier, 2
0: rectifier circuit, 21: comparison circuit.

Claims (1)

[Claims] 1. A microphone that collects noise, an A-characteristic amplifier that amplifies the output of the microphone by correcting the human frequency sensation, a squaring circuit that calculates the square of the output of the A-characteristic amplifier, and an output of the squaring circuit. A noise analyzer comprising an integrating circuit that integrates during a measurement time, and a display section that displays the integral amount integrated by the integrating circuit. An environmental noise measurement device characterized by comprising means for interrupting noise measurement during that time when the sound detected by the microphone exceeds a certain value that affects the noise measurement.