Larson Davis System 824, Technical Reference Manual

Page: 374 / 673

11-8 824 Reference Manual 9/29/09
Random Correction
The Random Corr setting gives you the option of turning on
a digital filter to provide the correction necessary to provide
a random incidence response when measuring with a 2540
or 377B41 free-field microphone.
See "Random Incidence Microphone
Correction" on page C-24 for the
random incidence correction filter’s
response. No - Random incidence correction is turned off.
Yes - Random incidence correction is turned on.
Autostore Settings Menu
Autostore
When a linear detector is selected,
the store rate is that of the linear
detector. Turns the Autostore function on or off. It allows the 824 to
measure and store basic information such as the Leq, Max,
and Min spectra when a measurement is ended by the
triggering setup or by pushing the run/stop key. When
Autostore is on, ByTime data is automatically stored in the
Autostore record if Save ByTime is set to Yes. For setups
with a linear detector, spectra are stored once every linear
detector time.
When an exponential detector is
selected, samples are stored every
(exponential detector time)
multiplied by the (exponential store
rate). For setups with an exponential detector, samples are stored
every 1/256 of a second (0,004 second) to every 32 seconds.
Pretrigger #
Pretrigger samples are only
available when the trigger function
is used to start the measurement. Allows the user to select the number of pretrigger samples
that are stored with an Autostore ByTime record. The 824
keeps a circular buffer of the most recent 400 samples. The
buffer is reset every time a new run is started. The number of
spectra in the buffer is displayed in the Trigger Status view.
This setting determines how many of these spectra to copy
into the beginning of the Autostore record.
• 0 - 400 samples
By default, the RT60-A and RT60-B
instruments have Autostore and
ByTime enabled.