Svantek SVAN 977A - Definitions and Formulas of SLM Results

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SVAN 977A 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
tp
maxlog10Peak
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
tp
maxlog10Spl
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
tp
maxlog10Max
T
Lmin
Minimal value of the time-weighted sound
pressure level for current time period of the
measurement (T)
( )








=

2
0
2
W
p
tp
minlog10Min
T
Leq
(equivalent
sound level)
Time-averaged sound level for current time
period of the measurement (T)
( )
( )








=

T
0
2
0
dtptr
T
1
log10Leq
p
2
wτ
(t)
τ = Fast
τ = Slow
τ = Imp
p
w
(t)
p(t)
p
2
w
(t)
Lpeak
Lmax, Lmin, Spl,
Ltm3, Ltm5
Leq,
SEL,
L(den),
LEPd