Larson Davis SoundAdvisor 831C Reference Manual page 148

SoundAdvisor Model 831C
Step 11.
Press the right softkey (
Step 12.
Select a Run Mode from the drop-down menu. This controls how the meter
ends a measurement and how history records are accumulated. The following
segments describe FFT Run Modes in detail.
Using Manual Stop
A Manual Stop measurement begins when you press the Run/Pause button
when you press the Stop/Store button
a.
Select Manual Stop as the Run Mode.
b.
If you select the checkbox in-line with Enable FFT History, a record is created
with each stop. You may make as many records (runs) as you like. The Overall
data includes data from all records.
Using Count Stop
A Count Stop measurement begins when you press the Run/Pause button
when the number of FFT averages calculated equals the value you set for FFTs in Average
(or you press the Stop/Store button
a.
Select Count Stop from the Run Mode drop-down menu.
b.
Enter a value for FFTs in Average.
Refer to the standard you're using for specifics on the number of averages
required for the measurement. The default value for FFTs in Average is 1, and
the max value is 99,999.
c.
If you select the checkbox in-line with Enable FFT History, enter a value for
Record Count, which is the number of records that should be created. The
default value is 1.
Using Timed Stop
Timed Stop measurement begins when you press the Run/Pause button
when the elapsed time for the measurement equals the value you set for Run Time. You
can also stop the measurement at any time by pressing the Stop/Store button
a.
Select Timed Stop as the Run Mode.
b.
Enter a Run Time in hours, minutes, and seconds.
The Minimum Timing (s) table on the FFT tab shows the time it takes to
compute the first FFT (based on your selected frequency resolution). The Run
Time for a Timed Stop measurement should be at least as long as the period
shown in the table.
When using a timer-based Run Mode, FFT measurements may not end
TAKE NOTE
on timed boundaries. This means that it's possible for the actual run time to be
slightly shorter than the period you enter for Run Time. A typical result is 19.4
seconds of measurement when entering 20 seconds Run Time.
c.
If you select the checkbox in-line with Enable FFT History, one FFT History
record is created for each run time.
//*
) to view the Control tab.
7
on the meter or in G4.
7
).
Creating an FFT Setup File On the Meter
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