3
Structure Features and Function
The outline of the Sound Level Meter is shown in Figure 1. It consists of microphone,
preamplifier and the main unit. During normal operation, the measuring microphone
and the preamplifier are installed on the head of the main unit, connected with the
main unit through knurled nut. Extension cable can also be used between the main unit
and the preamplifier. The function of the connector’s pin between preamplifier and the
sound level meter is shown in Figure 2.
The outline of the sound level meter is sharp to reduce the reflection of the sound wave.
The nominal influence caused by the reflection on the shell and the indication features
under different incidence direction can be found in annexes. The shell is mold with ABS
plastic. The batteries are put in battery box, which is very convenient for users to
replace the batteries just by taking off the battery cover plate. All buttons are located
at the central of the obverse side. Measuring results are shown on the 240×320 OLED
display.
The GPS antenna slot, SD card slot and SD card indicator are located on the side, AC
output (3.5mm phone jack), GPS and Status indicator, RS-232 and mini USB port are on
the bottom of the device, the detail definition and function of pins is shown in the
following figures.
