Larson Davis System 824, Reference Manual

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7-8 824 Reference Manual 11/8/00
Random Incidence Microphone
Correction - (Available to all
Instrument types)
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 2541 free-field microphone.
See Appendix C for the random inci-
dence 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. Cor-
rection 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 instanta-
neous 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 fea-
tures.
PK-II uses the normal weighting set-
ting. 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 averag-
ing characteristics for real-time frequency analysis. This set-
ting provides the following two options:
Slow - The frequency analysis uses exponential
averaging with a one second time constant.