BRUEL & KJAER 2203 Instructions And Applications

To further reduce the influence of the operator, an extension cable
may be used to remove the Microphone from the operator.
5.3. EFFECT OF BACKGROUND NOISE
If it is required to measure the noise produced by a particular source
e.g., an electric motor, best results would be obtained if it could be
measured in a quiet place. However, this is not always possible, so
measurements often have to be taken with background noise present. If
the noise level when the machine under test is shut down (i.e., the
background noise level) is more than 10 dB lower than that when the
machine is operating, then no correction for background noise is neces-
sary.
When the difference between "total" noise level and the background
noise level is between 3 and 1 0 dB an approximate correction may be
made by consulting the chart in Fig . 5.7. If the difference between "to-
tal" and background noise level is less than 3 dB, it is advisable to per-
form the measurements in a quieter place.
C> 7
c:
~
6
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0
~
.0
~ 3
a.>
.0
! 2
'C
-
0
~
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\
~
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2 3
........ ,.....,
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r-
t--
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4 5 6
7
8
9
10 dB
Difference between total reading and background reading 171139
Fig.5. 7. Correction for the influence of background noise
5.4. DISTORTION
The input stage will accept a maximum level of 1 OV RMS without
clipping. For a microphone with a sensitivity of 50 mV /Pa this corre-
37

BRUEL & KJAER 2203 Specifications

General

Brand	BRUEL & KJAER
Model	2203
Category	Measuring Instruments
Language	English