Extech Instruments 407790A, User Manual

Page: 30 / 55

30
407790A-EN_V2.4 1/20
4.3 Sound Level and Octave Band Analysis Measurement
1. With the power ON wait until the SLM measurement screen appears on the display.
2. Use the SLM 1/1 1/3 button to select the desired 1/1 OCT, 1/3 OCT or 1/1 & 1/3 OCT band or
SLM measurement screen.
3. Use the FREQ WEIGHT TIME button to select the frequency weighting characteristic. For normal
sound level measurements, select the “A” setting.
4. Use the FREQ WEIGHT TIME button to select the time weighting characteristic. For normal sound
level measurements, select the “F” (Fast) setting.
5. Use the

LEVEL

buttons to set the level range.
Select a setting in which the main channel all-pass value indicator is in the middle of the range.
If the “ OV ” or “ UN ” indicators appear, change the level range setting.
6. The level indicator displays the currently measured Sound band level.
Use the GRP/NUM button to toggle the measurement screen between graph and numeric display.
If the graph display is selected, use the

and

buttons to move the cursor to the desired
frequency band.
In the 1/1 & 1/3 OCT numeric display, frequencies that are currently not displayed can be called up
with the

and

buttons.
To stop or resume updating the band level indication press the PAUSE/CONT button. When
pause is selected, a pause symbol ( ) appears on the display.
Important: During sound band measurement, do not press the MODE key or other parameter
symbols will be displayed.
The sound band level is being displayed when there is no character string after the basic
indicator.
LAF: Sound band level is being displayed.
LAeq: Sound band level is not being displayed.