23
12. CALIBRATION
1) Prepare the optional " SOUND CALIBRATOR ", such as
" SC-941 " or " SC-942 " ( set range to 94.0 dB ). Power
on the Sound Calibrator & plug calibrator output socket
into the " Microphone " head ( 3-8, Fig. 1 ) of the
Sound Level meter.
2) Select " Time Weighting " at " Fast " position.
3) Select " A " weighting.
4) Adjust the " Calibration VR " ( 3-12, Fig. 1 ) carefully
with a " - " screw driver until the display reading value
within " 94 +/- 0.2 " dB.
13. FREQUENCY WEIGHTING
CHARACTERISTICS OF A & C
NETWORKS
Frequency
A Weighting
C Weighting
Tolerance
Charac.
Charac.
( IEC 61672
Class 2 )
31.5 Hz
-39.4 dB
-3 dB
±3.0 dB
63 Hz
-26.2 dB
-0.8 dB
±2.0 dB
125 Hz
-16.1 dB
-0.2 dB
±1.5 dB
250 Hz
-8.6 dB
0 dB
±1.5 dB
500 Hz
-3.2 dB
0 dB
±1.5 dB
1 KHz
0 dB
0 dB
±1.0 dB
2 KHz
+1.2 dB
-0.2 dB
±2.0 dB
4 KHz
+1 dB
-0.8 dB
±3.0 dB
8 KHz
-1.1 dB
-3 dB
±5.0 dB
Содержание PCE-NDL 10
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