User manual

291
Appendix
Sound Exposure Level
The sound exposure level L
AE
characterizes the
totalenergy content of a signal and corresponds to
the LAeq normalized to one second. The sound ex-
posure level is measured for example to compare
noise events with different time durations. The L
AE
reports the amount of noise from an event such as
an individual aircraft fly-over. An earlier used level
name is SEL.
L
AE
= L
Aeq
+ 10 x log (time in seconds)
Time-Average Sound Level or
Equivalent Continuous Sound Level in accor-
dance with IEC 61672
Moving Time-Average Sound Level or
Moving Equivalent Continuous Sound Level
With selectable time window from one second
up to one hour, four individual levels can be con-
figured. The moving time-average sound level is an
Leq based on a moving time window. This level is
also called “running Leq,T”, “gliding Leq,T” or “slid-
ing Leq,T”.
The measurement result is updated every second
for the first 60 seconds. Afterwards the update rate
is every five seconds. This is an example:
10h 00min 00sec St
art of XL2 measurement
1
0h 00min 05sec Leq5” = Leq of the 5 seconds
10h 00min 06sec Leq5” = Leq of the time win-
dow from 10h 00min 01sec to
10h 00min 06sec
10h 00min 07sec Leq5” = Leq of the time win-
dow from 10h 00min 02sec to
10h 00min 07sec