Explosion-proof individual noise dosimeter technical principle

A noise dosimeter, also known as an integral sound level meter, is an instrument used to measure noise exposure. Adding an integral device to the ordinary noise dosimeter line is a noise dosimeter.

It measures the amount of noise exposure over time. The noise dosimeter can be preset for a time T such that an equivalent continuous A level or Leq noise exposure is given together during the measurement time. The sound is converted into an electrical signal by the microphone, and the impedance is converted by the preamplifier to match the microphone to the attenuator. The amplifier adds the output signal to the weighting network, performs frequency weighting (or external filter) on the signal, and then amplifies the signal to a certain amplitude through the attenuator and the amplifier, and sends it to the RMS detector (or externally pressed) Flat recorder), the value of the noise level is given on the indicator head.

The frequency weighting network in the noise meter/noise dosimeter has three standard weighting networks: A, B, and C.

The A network is a response to the 40-square pure tone of the human ear's equal-acquisition curve. Its curved shape is opposite to the 340-square equal-cord curve, so that the middle and low frequency bands of the electrical signal have a large attenuation.

The B network is a simulation of the human ear's response to the 70-square pure tone, which causes a certain attenuation of the low frequency band of the electrical signal.

The C network simulates the human ear's response to 100-square pure tone, with a nearly flat response over the entire audio range.

According to the sensitivity of the noise dosimeter, there are two types of methods for classifying noise dosimeters: one is the ordinary noise dosimeter, which is not very demanding on the microphone. The dynamic range and the frequency response are relatively narrow, and generally do not have a bandpass filter associated; the other is a precision noise dosimeter, which requires a wide frequency response, high sensitivity, long-term stability, and A bandpass filter is used together, and the amplifier output can be directly connected to the level recorder and the recorder to display or store the noise signal.