Svantek SV 971A, Руководство пользователя

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SV 971A User Manual
– Appendixes
209
Table C.1.2. Linear operating ranges for the Low measurement range (for the sinusoidal signal and
microphone sensitivity 32 mV/Pa)
[dB]
L
AS/F
L
BS/F
L
CS/F
L
ZS/F
L
AeqT
L
BeqT
L
CeqT
L
AE
L
Cpeak
(t
int
= 2 s)
from to from to from to from to from to from to from to from to from to
31.5 Hz 24 83 24 106 24 120 32 123 24 83 24 106 24 120 27 86 50 123
500
Hz
24
119
24
122
24
123
32
123
24
119
24
122
24
123
27
122 50 126
1 kHz 24 123 24 123 24 123 32 123 24 123 24 123 24 123 27 126 50 126
4 kHz 24 124 24 122 24 122 32 123 24 124 24 122 24 122 27 127 50 126
8 kHz 24 122 24 120 24 120 32 123 24 122 24 120 24 120 27 125 50 123
12.5 kHz 24 118 24 117 24 117 32 123 24 118 24 117 24 117 27 121 50 120
Note: For the signals with the crest factor n > 1.41 upper measuring range of the RMS (LEQ
and SPL) is reduced. The valid upper limit can be calculated according to the below given
formula: , where A is the upper limit for the sinusoidal signal
Example: For the crest factor n = 10 the upper limit is A10 = 120 dB
Measuring ranges
Reference measuring range of the acoustic pressure Normal
Measuring frequency range of the acoustic pressure (-3 dB) 5
Hz ÷ 20 000 Hz.
Basic measurement error of the acoustic pressure < 0.7 dB (measured for the reference
conditions, see below).
Weighting filters (see Chapter C.3)
Z meeting requirements of the IEC 61672-1:2013 standard for the Class 1
“
Z
“ filter
A meeting requirements of the IEC 651 and IEC 61672-1:2013 standard for the Class
1 “
A
” filter
B meeting requirements of the IEC 651 and IEC 61672-1:2013 standard for the Class
1 “
B
” filter
C meeting requirements of the IEC 651 and IEC 61672-1:2013 standard for the Class
1 “
C
” filter
Table C.1.3. Self-generated noise for different weighting filters
Electrical *) Acoustical compensated
Weighting filter
Range
A C Z A C Z
Low < 12 dB < 12 dB < 20 dB < 17 dB < 17 dB < 23 dB
Normal < 16 dB < 16 dB < 23 dB < 20 dB < 20 dB < 27 dB
*) measured with the ST 03 microphone equivalent impedance 18 pF@100kOhm
± 10%
Special filters
•
Diffuse Field compensation filter that improves the complete instrument
frequency response in the diffuse acoustic field (see below)
•
Windscreen compensation filter that improves the instrument frequency
response in the free acoustic field when windscreen SA 22 is
mounted on the microphone (see Chapter C.1.2)
( )
2 log 20 137 n A
n
− =