Instruction manual

42
Sound Pressure Level Measurement
The NA-27 offers various kinds of measurements: instantaneous value (L
p
, L
max
, L
min
,
L
peak
), power (L
eq
, L
E
, L
tm3
, L
tm5
), and percentile value (L
x
). The maximum sound pressure
level (L
max
), minimum sound pressure level (L
min
), and waveform peak hold (L
peak
) refer
to the instantaneous level within the measurement time. Except for the instantaneous level
(L
p
), the measurement applies to the preset measurement time.
Note
If measurement settings such as level range or frequency
weighting were changed during pause in instantaneous
value mode, the new settings will apply immediately when
pause is released.
If measurement settings such as level range or frequency
weighting were changed after processing, the new settings
will be effective only when processing the next measure-
ment.
Power-on
When the power switch on the side of the unit is set to ON, the indication "Now
selftesting!!" appears on the display. After initialization and self-test are completed (be-
tween 10 and 20 seconds), the unit is ready for operation.
If a backup battery is inserted, the unit will in principle be set to the same condition as
before, except for the items shown in the table below.
If no backup battery is inserted, the indication "Backup Battery Empty!!" appears after
turning on the power. Insert a backup battery as described on page 16. When wishing to
use the unit without a backup battery, simply press any key to make the indication disap-
pear. In this case, the memory store function and date and time functions are not available.