Larson Davis System 824, Technical Reference Manual

Page: 133 / 673

9/29/09 System 824 Views 5-13
Select “Spectrum” to view the graph again.
Time History Displays The following are examples of the graphical displays for the
SLM Time History and RTA Time History Views:
The up
u
and down
d
arrow keys change the record
you are viewing. The
r
or
l
arrow keys change the
position of the cursor.
SSA Intervals
NOTE: SSA Intervals are only available
when the LOG option is installed.
See the section "Intervals" on page
5-44 for a description of the
Interval-a through Interval-d
displays. The Interval History shows a record of various sound
pressure data and spectral data (including spectral LNs)
gathered in time segments over the run time of the 824. An
example would be a measurement where data is gathered in
one hour time intervals over a 24 hour period.
Only Min or Max can be displayed. The SSA instrument has 4 unique interval displays which
show the
Max spectra (at the time the broadband level was at
maximum), Min spectra , which is a bin by bin minimum, the
Leq or average of each frequency over the interval period
and Leq By Time which shows the level for each frequency
from each interval record over time.