A-8 824 Reference Manual 9/12/00
T is the measurement duration in hours
t is the time in hours
L is the SLOW, (or FAST) A-weighted sound level, a func-
tion of time, when the sound level is greater than or equal to
L
, or equals -× when the A-weighted sound level is less than
L
t
L
t
is the threshold sound level specified by the manufacturer
L
C
is the criterion sound level specified by the manufacturer
Q is the exchange rate in dB, and
q
= the parameter that
determines the exchange rate, where:
q = 10 for a 3dB exchange rate
q = 5/log(2) for a 5dB exchange rate
q = 4/log(2) for a 4dB exchange rate
The factor of 100 in the equation produces a result that is a
percentage.
Dose is obtained from the accumulations made for TWA and
SEL using the formula:
where,
L
(s)
is the current SPL at sample
s
; for measurements that
include a threshold
L
(s)
is set to × if
L
(s)
is less than the
Threshold Level
L
t
k is the exchange rate constant which is equal to:
10.00 for an exchange rate of 3dB (L
eq
, or Ý 3dB/log(2))
DOSE
10
10
L
s
()
k
----------
s
1=
n
∑
L
c
k
-----
T
c
115200
()
100
()
log+log––log
%=
To Next Page
Loading...
