Svantek SV 973 User Manual

SVAN 973 User Manual – Appendixes
199
APPENDIX D. DEFINITIONS AND FORMULAE OF MEASURED VALUES
D.1 BASIC TERMS AND DEFINITIONS
T
Current time period of the measurement in seconds.
1
T
Last second of the measurement.
e
T
Exposure time in seconds (time period during which a person is exposed to the action of
noise). This parameter can be set in the Exposure Time setup (Measurement menu).
The available values are from 1 minute to 12 hours with 1-minute step.
h8
T
Time period equal to 8 hours (28 800 seconds).

Exponential time constant in seconds for the giving time-weighting. Three time constants
are available: Slow (1000 ms), Fast (125 ms), Impulse (35 ms, but on falling values a
longer time constant of 1500 ms is applied).
W
Frequency-weighting filter: A, C, B or Z.
( )
tp
W
Instantaneous frequency-weighted sound pressure with the weighting filter W. Sound
pressure is expressed in pascals (Pa).
( )
tp
W
Instantaneous frequency and time-weighted
sound pressure with the weighting filter W
and time constant

calculated from the
equation:
( ) ( )
( )

−
=
−−


t
/t
dep
1
tp
2
WW
where:

– variable of integration.
( )
tr
Instantaneous sound pressure depends on
the <RMS Integration> parameter:
( )
( )
( )



=
=

=
Exp nIntegratioRMS
Lin nIntegratioRMS
tp
tp
tr
W
W
0
p
Reference value (20 Pa).
( )
xlog
Logarithm of x to the base 10.
Q
Exchange rate in decibels is equal to 2, 3, 4, 5 or 6. The value of Q influences the
calculations of 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.
q
Value of q is used in the calculations of
DOSE, D_8h and LAV is taken from the
formula





=

=
3Q10
3Q
2log
Q
q
for
for

Svantek SV 973 Specifications

General

Brand	Svantek
Model	SV 973
Category	Measuring Instruments
Language	English