Instruction manual

35
Calibration
Before starting a measurement, the unit must be calibrated. There are two
types of calibration, namely electrical calibration using an internally gener-
ated signal and acoustic calibration using an external sound calibrator.
Internal calibration (Electrical calibration)
Calibration is carried out using a signal generator (1 kHz, sinusoidal wave)
built into the unit.
1. Press the CAL key. A calibration screen such as shown below appears.
Verify the “Internal Calibration” is displayed in the upper part of
the screen.
If “Acoustic Calibration” is shown in the upper part of the screen,
press the DISPLAY key. The calibration mode will change to “In-
ternal Calibration”.
2. Con rm that the calibration value indication shows 124 dB steadily.
If the bar graph upper limit setting is not 130 dB, a value of [Output
Level Range Upper -6 dB] will be  ashing as the “124 dB” value on
the calibration value indication.
3. Use the keys to bring the level indication to the speci ed value
(124.0 dB).
4. When calibration to 124.0 dB is completed, press the CAL key once
more to return to the measurement screen.