CESVA DC112 - 7 Appendix A: Functions; Definition of Functions; Continuous Equivalent Sound Pressure Level; Peak Sound Pressure Level

DC112d/DC112
User’s manual
35
7. Appendix A: Functions
7.1 Definition of functions
7.1.1 Continuous equivalent sound pressure level
L
T
and L
t
This is the linear average of the instantaneous sound pressure square from
the beginning (t
1
) to the end (t
2
.) The duration of the measurement is therefore T= t
2
- t
1
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
⋅=
∫
2
1
t
t
2
0
2
eqT
dt
p
(t)p
T
1
log10L
pt: instantaneous sound pressure
p
0
: reference sound pressure (20 µPa)
T: duration of the averaging
The equivalent continuous sound pressure level function is ideal for measuring variable
sound events such as compressors or sound events that due to their long duration cover a
wide range of sound pressure levels, such as machinery measurements.
The DC112d/DC112 measures the equivalent continuous sound pressure level
L
t
and
L
T
.
The equivalent (
L
t
) level is the equivalent level of the interval measured, that is, for each
instant it gives us the value of the equivalent level from the beginning of the measurement
to that instant. When a measurement has been completed, the
L
t
value corresponds to
the equivalent level of the entire measurement from beginning to end.
The equivalent level (
L
T
) is the equivalent level corresponding to T integration time (a
programmable parameter). It is displayed every T time period. In other words, every T
time period the DC112d/DC112 shows the equivalent level of the last T time period.
7.1.2 Peak sound pressure level
L
peak
(Peak) The highest absolute instantaneous sound pressure value since the
beginning of the measurement, in decibels.
7.1.3 Equivalent daily exposure level
L
EX,8h
Equivalent daily noise exposure level normalized to 8 hours, with A
frequency weighting
)lg(10
08,
TtLL
AthEX
+
=
L
At
: Equivalent continuous sound pressure level with A frequency
weighting corresponding to the measurement time
t: Measurement time
T
0
: Normalization time (8 Hours)