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Chapter 11
Function Equations
The following tables describes mathematically how the functions available on the
range of Sonus Pocket Meters are calculated.
All calculations displayed are subject to rounding and/or truncation and are
based on the equations from the IEC standard 61672-1 where applicable.
Function
Equation
Equivalent
Continuous
A-weighted
Sound
Pressure Level
L
AeqT
20 log
⋅
1
T
t T
−
t
ξ
P
A
( )
2
ξ
( )
⌠
⌡
d
1
2
Po
⋅
dB
:=
L
AeqT
10 log
⋅
1
T
0
T
t
P
A
( )
2
t
( )
⌠
⌡
d
P
o
( )
2
⋅
dB
:=
ξ
is a dummy variable of time integration over the
averaging time interval ending at the time observation t
T is the averaging time interval
P
A
(
ξ
) is the instantaneous A-weighted sound pressure
P
o
is the reference sound pressure of 20µPa
In the equation above, the numerator of the argument of
the logarithm is the root-mean-square, frequency-weighted
sound pressure over averaging time interval T
