The function of sound level meter detector and indicator head
In order for the amplified signal to be displayed through the meter, a detector is also needed to convert the rapidly changing voltage signal into a slower changing DC voltage signal. The magnitude of this DC voltage is proportional to the magnitude of the input signal. According to the needs of measurement, the detectors are divided into peak detectors, average detectors and black root mean square value detectors. The peak detector can give the maximum value in a certain time interval, and the average detector can measure the absolute average value in a certain time interval. Except for pulse sounds such as gunshots, which need to measure their peak values, square root detectors are used in most measurements.
The root mean square value detector can square, average and square the AC signal to obtain the root mean square value of the voltage, and finally transmit the root mean square voltage signal to the indicating meter. The indicator meter is an electric meter. As long as the scale is calibrated to a certain extent, the decibel value of the noise level can be read directly from the meter. The damping of the sound level meter head generally has two levels: "fast" and "slow". . The average time of the "fast" gear is 0.27s, which is very close to the physiological average time of the human hearing organ; the average time of the "slow" gear is 1.05s. When measuring steady-state noise or recording the sound level change process, it is more appropriate to use the "fast" gear; when the measured noise fluctuates relatively large, it is more appropriate to use the "slow" gear.
In order to meet the needs of the measurement site, the sound level meter generally has a tripod stand, so that it can be fixed on the tripod stand as needed.
There are usually some jacks on the panel. If these jacks are connected to a portable octave band filter, they can form a small simple spectrum analysis system for on-site use; if combined with a tape recorder, the on-site noise can be recorded on a tape and stored for later use. More detailed research will be conducted later; if combined with an oscilloscope, the waveform of the sound pressure change can be observed, and the waveform can be captured with a camera; analyzers, recorders and other instruments can also be combined and used with sound level meters, This depends on the test conditions and test requirements.\\
