Detector and indicator of level meter
In order to display the amplified signal through the meter, a detector is also needed to convert rapidly changing voltage signals into slower changing DC voltage signals. The magnitude of this DC voltage should be proportional to the magnitude of the input signal. According to the measurement requirements, detectors can be divided into peak detectors, average detectors, and root mean square detectors. The peak detector can provide the maximum value within a certain time interval, while the average detector can measure its average value within a certain time interval. Except for pulse sounds like gunshots that require measuring their peak values, root value detectors are commonly used in most measurements.
The root mean square detector can square, average, and square root of the AC signal to obtain the root mean square value of the voltage, and finally transmit the root mean square voltage signal to the indicator head. The indicator head is an electric meter, and as long as its scale is calibrated to a certain extent, the decibel value of the noise level can be directly read from the head. The damping of the sound level meter head generally has two gears: "fast" and "slow". The average time for "fast" mode is 0.27s, which is very close to the physiological average time of the human auditory organ; The average time for "slow" gear is 1.05s. When measuring steady-state noise or recording the process of sound level changes, using the "fast" mode is more appropriate; When the fluctuation of the measured noise is relatively large, using the "slow" gear is more appropriate.
To meet the needs of the measurement site, sound level meters generally have triangular brackets, which can be fixed on the triangular brackets as needed.
There are usually some sockets on the panel. If these sockets are connected to portable octave band filters, they can form a simple spectrum analysis system for small on-site use; If combined with a tape recorder, the on-site noise can be recorded and stored on magnetic tape for further detailed research; If compared to an oscilloscope"
