Noise meter - sensitivity calibration and noise sources
To ensure measurement accuracy, calibration should be performed before and after use.
Connect the sound level calibrator to the microphone, turn on the calibration power, read the value, adjust the sensitivity potentiometer of the noise meter, and complete the calibration.
Noise meter - influencing factors
Noise meters are mainly used to measure noise, and there are several classifications for noise measurement:
1. From the perspective of measuring objects, it can be divided into the measurement of environmental noise (sound field) characteristics and the measurement of sound source characteristics.
2. According to the temporal characteristics of the sound source or field, it can be divided into steady-state noise measurement and non-stationary noise measurement. Unsteady noise can be divided into periodic variation noise, irregular variation noise, and pulse sound.
3. According to 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. According to the required accuracy of measurement, it can be divided into precision measurement, engineering measurement, and noise survey.
Noise meter - Standard regulations
In order to compare the measurement results of sound level meters produced by countries around the world, the International Electrotechnical Commission (IEC) has developed relevant standards for sound level meters and recommended their adoption by countries. In May 1979, the IEC651 "Sound Level Meter" standard was passed in Stockholm, and the national standard for sound level meters in China is GB3785-83 "Electrical and Sound Performance and Testing Methods for Sound Level Meters". In 1984, IEC passed the international standard IEC804 "Integral Average Sound Level Meter", and China promulgated GB/T17181-1997 "Integral Average Sound Level Meter" in 1997. They are consistent with the main requirements of IEC standards. In 2002, the International Electrotechnical Commission (IEC) released the new international standard IEC61672-2002 "Sound Level Meters". This standard replaces the original IEC651-1979 "Sound Level Meter" and IEC804-1983 "Integral Average Sound Level Meter". China has formulated the JJG188-2002 "Sound Level Meter" verification regulation based on this standard. According to the new standards, sound level meters can be classified into general sound level meters, integral sound level meters, spectral sound level meters, etc., and can be classified into level 1 and level 2 according to accuracy. The various performance indicators of the two levels of sound level meters have the same central value, only the allowable error is different, and as the level number increases, the allowable error is relaxed. According to volume, it can also be divided into desktop, portable, and pocket sound level meters. According to its indication method, it can be divided into analog indication and digital indication sound level meters.
