Extech Instruments 407790 - Page 10

Model 407790 Ver. 1.1 7/02L
10
Instantaneous sound pressure level measurement (L
A
, L
C
, L
P
)
To perform a measurement, carry out the following steps.
1. Set the power switch to ON and wait until the measurement screen appears.
ID No: 00001358 Ver: 0.10
SOUND LEVEL METER
1/1 & 1/3 Octave Band
Real-Time Analyzer
Self-Testing...
[ SLM ] 01 / 07 / 27 14:26:39
A
L
30 80
FAST
dB
130
2. Press the SLM/ 1/1/ 1/3 button to select the desired SLM, 1/1 or 1/3 octave band
sound pressure level measurement screen.
70
500
[ 1 / 1 OCT ] 01 / 07 / 27 14:26:39
125Hz 31.5
30
50
8k L W2k
A
FAST
L
90
dB
75.2 dBW
40
60
100
80
[ 1 / 3 OCT ] 01 / 07/ 27 14:26:39
31.5Hz
30
50
70
2k500125 8k L W
A
FAST
90
dB
L W 75.2 dB
100
60
80
40
3. Use the FREQ WGHT button to select the desired L
A
, L
C
or L
P
frequency weighting
setting.
4. Use the TIME CONST button to select the desired FAST or SLOW time constant
setting. Normally, the “FAST” setting should be used.
5. Use the

LEVEL

button to select the range. Choose a setting in which the “OVER”
and “UNDER” indications do not appear. In SLM mode, the dynamic range is
30~130dB so the

LEVEL

button is not used.