Application of Sound Level Meter Weighting in Custom Frequency
In the AWA6228 multifunctional sound level meter and AWA6291 real-time signal analyzer, in addition to the A, C and Z frequency weighting characteristics designed according to the standard, a user-defined frequency weighting function is added. The frequency weighting factor is set at the octave center frequency point. When the instrument performs 1/3 octave real-time spectrum analysis, the measured sound pressure level of each 1/3 octave band is weighted according to the set custom frequency The factors are weighted and then synthesized into a custom weighted sound level.
For example, in JGJ/T 170-2009 "Urban Rail Transit Caused Building Vibration and Secondary Radiated Noise Limits and Measurement Method Standards", it is required to measure indoor secondary radiated noise with a frequency range of 16 Hz~200 Hz, which can be Using the custom frequency weighting function, under the custom frequency weighting menu, set the weighting factors of each 1/3 octave center frequency within the frequency range of 16 Hz to 200 Hz to A specified by the sound level meter standard weighting factor (see table), and set the weighting factors of other center frequency points to -INF (ie -∞).
The instrument will measure the self-defined weighted sound pressure level while measuring other parameters according to the self-defined weighting factor, and express it with W-U. Here, the indoor secondary radiation noise in the frequency range of 16 Hz~200 Hz is directly read out. The sound pressure level value, which can be an instantaneous value, or an equivalent sound level, a maximum sound level, or a minimum sound level.
