Svantek SVAN 958A - Definitions and Formulas of the Results (SLM Mode)

292
SVAN 958A User Manual
L
T
Threshold sound level, set in the Threshold Level (path: Menu / Input / Dosimeter Setup).
The available values are as follows: None, 75dB, 80dB, 85dB or 90dB.
L
c
Criterion sound level, set in the Criterion Level (path: Menu / Input / Dosimeter Setup). The
available values are as follows: 80dB, 84dB, 85dB or 90dB.
Q
Exchange rate in decibels
equal to 2, 3, 4 or 5, set in the
Exchange Rate position (path:
Menu / Input / Dosimeter Setup).
The value of Q influences the
calculations of acoustic dose
meter results, namely DOSE,
D_8h and LAV. The exposure
rate equal to 3 complies with
ISO R 1999 “Assessment of
Occupational Noise Exposure
for Hearing Conservation
Purposes”, while Q equal to 5
complies with the American
“Occupational Safety and Health
Act” – OSHA. The value of q
used in the calculations of
DOSE, D_8h and LAV is taken
from the formula:





=

=
3Qfor10
3Qfor
2log
Q
q
L(t)
Sound level (a function of time)
measured with the selected
time constant Impulse, Fast or
Slow (path: Menu / Input /
Channels Setup / Channel x
Setup) and the weighting filter (A,
C, Z or G)
0
w
p
)t(p
log20)t(L
=
L
d
(t)
Sound level (a function of time), depends on the selected threshold level.
In case when the None option
was selected
L
d
(t) = L(t)
In other cases (when the
Threshold Level is equal to
75dB, 80dB, 85dB or 90dB)



−

=
T
T
d
L)t(Lfor
L)t(Lfor)t(L
)t(L
D.1.2 Definitions and formulas of the results (SLM mode)
OVL
Percentage of the overloaded input signal, which occurred during the current time period of
the measurement (T)