Introduction to the Sensitivity of Noise Meters
The sensitivity of a noise meter is generally composed of a capacitive microphone, preamplifier, attenuator, amplifier, frequency meter network, and effective value indicator head. It is the most basic instrument in noise measurement. The correct use of a noise meter directly affects the accuracy of the measurement results.
The correct measurement method is to select the correct gear according to the situation when measuring, and to hold the noise with both hands flat
The response of the noise meter head can be divided into four types based on sensitivity: fast slow and numerical hold. Let's briefly introduce it below.
1. Quick. The time constant of the meter head is 125ms, which is generally used to measure unstable noise and transportation noise with significant fluctuations. The fast gear approaches the human ear's response to sound.
2. Slow. The time constant of the meter head is 1000ms, usually used for measuring steady-state noise, and the measured value is the effective value.
3. Peak Hold. The rising time of the watch needle is less than 20ms. It is used to measure pulse sounds with a short duration, such as guns, guns, and explosions. The measured value is the peak value, which is the maximum value. Distance measuring instrument, height measuring instrument, laser projection instrument, flow meter, GPS thickness measuring instrument, level gauge, flat meter, waveform recorder, testing fixture, voltage and current recorder, data collector, graphic recorder, flow integrating instrument.
4. Pulse or pulse hold. The rise time of the watch needle is 35ms, used to measure pulse noise with a longer duration, such as punching machines, press hammers, etc. The measured value is the maximum effective value.
Noise meters can be classified according to different elements
1. From the measurement object, it can be divided into feature measurement of environmental noise (sound field) and measurement of sound source features.
2. From the time characteristics of the sound source or field, it can be divided into steady-state noise measurement and non-stationary noise measurement. Non steady state noise can also be divided into periodic variation noise, irregular variation noise, and pulse noise.
3. From the frequency characteristics of the sound source or field, it can be divided into broadband noise, narrowband noise, and noise containing prominent pure tone components.
4. From the perspective of measurement accuracy requirements, it can be divided into precision measurement, engineering measurement, and noise survey.
