B-6 824 Reference Manual 9/29/09
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))
13.29 for an exchange rate of 4dB (L
DOD
, or = 4dB/log(2))
DOSE 10
10
L
s
k
----------
s 1=
n
L
c
k
-----
T
c
115200100log+log––log
%=
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