Instruction manual

132
Optional Accessories
4. Press the CAL key once more to return the NA-27 to the measurement mode.
5. Use the FREQ WEIGHT key of the NA-27 to set the frequency weighting charac-
teristics.
The time constant should be set at the level recorder.
6. Use the LEVEL UP/DOWN keys to set the level range. Choose a setting in which
the "OVER" and "UNDER" indications do not appear.