Larson Davis System 824, Technical Reference Manual

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9/29/09 Using ID Setting Files 7-9
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.
NOTE: Interval Spectral LNs will not be available when
R.I. Correction is turned on. Overall Spectral LNs will only
be available when the 824 is stopped. This means that the
overall Spectral LN data will not be viewable when the 824
is running. If you try to view the overall Spectral LN data
while the 824 is running the message “Calculating/Stop to
View” will be displayed.
Pk Weighting - (SSA, LOG, ISM)
The 824 has peak detectors for A, C, and Flat frequency
weighting that measure simultaneously the greatest
instantaneous level (L
pk
) that has occurred since the last
current or overall reset. Some histories and event counters
are only able to evaluate one of the three peak detectors. The
Peak Weighting Setting selects which is to be used for these
features.
PK-II uses the normal weighting
setting.
Peak Weighting allows you to select either A, C, or Flat
weighting for the primary peak detector, PK-I.
This setting provides the following three options:
A - The A-weighted peak detector is used.
C - The C-weighted peak detector is used.
Flat - The Flat Weighted peak detector is used.
RTA Detector Setting - (SSA)
With the RTA Detector setting you can set the time
averaging characteristics for real-time frequency analysis.
This setting provides the following two options:
Slow - The frequency analysis uses exponential
averaging with a one second time constant.
Fast
-
The frequency analysis uses exponential
averaging with a 1 ⁄ 8 second time constant which
allows more variability to appear in the measure-
ment.