Svantek SVAN 979, User Manual

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SVAN 979 User Manual - Appendixes
D.1.2 Definitions and formulas of SLM results
The instrument calculates the sound measurement results for three profiles. The calculation flow diagram for one
profile is presented below:
Ovl Percentage of the overloaded input signal, which occurred during the current time period of the
measurement (
T )
Lpeak Peak sound level is calculated for the given T
( )






=
2
0
2
W
p
t p
max log 10 Peak
T
Spl or LXY Maximal value of the frequency and time-
weighted sound pressure level
for the last
second of the measurement
( )






=

2
0
2
W
1
p
t p
max log 10 Spl
T
Lmax Maximal value of the time-weighted sound
pressure level
for current time period of the
measurement ( T ). The Max result for the 1
second period is equal to the value of the Spl
result
( )






=

2
0
2
W
p
t p
max log 10 Max
T
Lmin
Minimal value of the time-weighted sound
pressure level for current time period of the
measurement ( T )
( )






=

2
0
2
W
p
t p
min log 10 Min
T
Leq
(equivalent
sound level)
Time-averaged sound level for current time
period of the measurement (
T )
( )
( )








=

T
0
2
0
dt p t r
T
1
log 10 Leq
p
2
wτ
(t)
τ = Fast
τ = Slow
τ = Imp
p
w
(t)
p(t)
p
2
w
(t)
L
peak
L
max,
L
min,
Spl,
LTeq
L
eq,
SEL,
L(den),
LEPd