Larson Davis 831, User Manual

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Model 831 Manual Exiting Settings Screen 4-15
and/or the night accordingly and also to choose the time for
the start of the day.
To accommodate these and other possible modifications, the
Day/Night tab permits the user to modify the times for the
beginning of the Day, Evening and Night periods and the
penalties to be utilized when calculating 24-hour integrated
values.
CNEL
In the state of California, a commonly used community
noise descriptor is Community Noise Equivalent Level
(CNEL), defined by the following formula:
This is essentially the same as the L
DEN
using default
values, with the exception that the evening period begins at
22.00 instead of 23.00. Thus, by making this change in the
L
DEN
settings, the measured value will represent CNEL.
Exiting Settings Screen
To exit the Settings Screen, press the Center Softkey labeled
Close .
If any setup parameters have been changed, the “Apply
Changes” message box will be displayed as shown in
FIGURE 4-13.
FIGURE 4-13 Apply Changes
CNEL
10log
10
1
24
------
10
L
i
10 +
 
10

0000
0700

10
L
i
10

0700
1900

10
L
i
5 +
 
10

1900
2200

10
L
i
10 +
 
10

2200
2400

+ + +
 
 
 
=