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as frequency at specific sound pressure level(SPL). Sometimes, Phon unit is used instead of SPL.
Phon is same to the SPL at 1kHz. For example, the curve passing on 80dB at 1kHz is called ‘80phon
curve’. The definition of weighting functions is listed in <Table V-4-1>.
<Table V-4-1> Various Weighting Filer
Weighting Term
Curve Definition
Remarks
A-weight
Reciprocal of 40phon Curve
Useful in Noise Analysis
B-weight
Reciprocal of 70phon Curve
-
C-weight
Reciprocal of 100phon Curve
-
D-weight
-
Useful in Airplane Noise Analysis
E-weight -
-
Normal Equal Loudness Contour is shown in [Fig. V-4-1], the frequency responses of each
weighting function are shown in [Fig. V-4-3].
[Fig. V-4-1] Normal Equal Loudness Contours
Summary of Contents for SLA-PA201
Page 64: ...64 Appendix 1 The Theory for calculating RMS by ISO2631 and ISO8041 ...
Page 67: ...67 Appendix 2 Frequency Response of Filter in the Vibration Level Meter ...
Page 75: ...75 Appendix 3 Theory of WBCombined Filter and Frequency Response ISO6954 Filter ...
Page 79: ...79 Fig 2 Lowpass Filter with 100Hz Cutoff Fig 3 a v transition Frequency Response ...
Page 88: ...88 Fig 12 Error between theoretical value and measured value ...
