Norsonic nor140, Instructional Manual, Page: 108 / 220

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Chapter 18
Sound recording
Recording duration
The duration of a recording can be set from 1s in one
second steps up to 9999 s (close to three hours). If the
duration is set to 0, the record length will have no limit.
This means that the record will last to the end of the
measurement or until the storing device is filled.
Note that for event triggered recordings, the speci-
fied duration will indicate the maximum duration – the
duration will otherwise be set by the condition for
triggering.
Making a recording
The start of a recording may either be done manually
by pressing the
RECORD
key or if trigger option is in-
stalled, by supplying an external trigger signal (as from
a remote button) or based on a noise event detected
by the instrument. If the trigger option is not installed,
only the manual start of the recording without any de-
lay is available.
For a level triggered recording the recording will start
during a measurement if the level in the selected net-
work or filter band exceeds the pre-set level. The length
of the recording is selected as a part of the setup.
From the trigger menu, the delay in starting the
sound recording can be set from -99 seconds up to
99 seconds. This allows the recording to start up to 99
seconds
before
you pressed the record button or the
trigger condition was fulfilled.
The recording file is automatically assigned to the cur-
rent measurement. When the level versus time display
is selected, the time for the recording will be marked
adjacent to the time axes. See figure below. The audio
file itself can not be seen in the Recall function picture.
You can use the program NorXfer to transfer the files to
your PC for further examination or analysis.
Mark
Recording mark
Please note that use of pre-trigger (nega-
tive trigger delay) of more than 5 seconds
(-6s to -99s) in reality means that the instru-
ment is storing the audio recording file
continuously in order to be prepared for any possible
audio trigger. This may bring the internal processor
up to its maximum capacity which then will results
in slow update of the display screen or in extreme
cases even an automatic turn-off of the recording in
case of a processor work overload (marked with a
W in the display).
If this problem occurs with the current setting, the
user may reduce the processor capacity by altering
any of the following settings:
- Reduce the audio recording quality (8 or 16 bit
instead of 24 bit, 12kHz sampling instead of
48kHz)
- Avoid use of large capacity SD-cards (remember
that several small SD-cards is safer than only one
large SD-card)
- Limit the audio recording pre-trigger (negative
trigger delay) to less than 6 seconds (-5s to 99s)
- Limit the number of selected L(t) parameters
- Increase the selected level vs. time profile
resolution
- Avoid use of the
PAUSE/CONT
feature