Stanford Research Systems SR780, Operating Manual And Programming Reference

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1-64 Exceedance Statistics
Use the knob to select (L) and press [Enter].
Choose L (L
eq
) as the sound level bin. L
eq
is a
standard broad band sound measurement. The result
is displayed as the last bin in the display and is
labeled ‘L’.
Press [Auto Scale A]
Scale DisplayA to show the entire range of the data.
6. Press [Waterfall]
Select the Waterfall menu. L
n
is calculated from
measurements stored in the waterfall buffer.
Press <Storage> Select waterfall Storage.
Use the knob to select (One Shot) and press
[Enter].
Choose One Shot to fill the waterfall buffer once
and stop.
Press <Total Count>
Change the number of measurements to store in the
waterfall buffer.
Press [1] [0] [0] [Enter]
Enter the Total Count for both displays (100).
The Storage Interval is 100 ms. A measurement
snapshot is added to the waterfall buffer every
Storage Interval so 100 measurements will take 10 s
to complete.
Press [Start/Reset] Start the measurement. This resets the waterfall
buffer. New measurements are added to the
waterfall buffer every 100 ms. The number of
records stored in the waterfall is shown in the
Vertical Scale Bar and increments to 100.
Because the waterfall storage is One Shot, the
waterfall buffer fills once (100 records). No more
records are added after 10 seconds.
7. Press [Analysis]
Select the Analysis menu.
Press <Exceedance Stats>
Select the Exceedance Statistics menu.
Press <Stop Index>
The exceedance is calculated using the records in
the waterfall buffer starting with the Start Index (0
is the most recent record) and continuing through
the Stop Index (Total Count - 1).
Press [9] [9] [Enter].
Enter 99 to include records 0 through 99 (100 total).