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though, by placing the weighting designation following the
“dB” units indication associated with the numerical output.
The actual measurement time is also provided for each TWA
value to fulfil the time interval description requirements.
For example, the System 824’s Logging SLM Overall-a dis-
play shows the current SPL (Sound Pressure Level) in 1/
10th decibel (dB) resolution. The actual real-time resolution
is 1/32nddB. The displayed SPL is followed by the text
“dB” and then the frequency weighting in effect—set to
A
in
this example.
The System 824’s Logging SLM Overall-e display shows
the overall measurement period and TWA. In this case the
measurement is Leq (because of the 3dB exchange rate).
The quantity is A-weighted and has a measurement elapsed
time of 11:43.1 (11 hours, 43 minutes, and 1 second).
Elapsed measurement time, shown as mm:ss.ss,
hh:mm:ss or hhhhh:mm
Scrolling SPL history
Current SPL while running or at the time a stop
occurred
The currently-selected frequency weighting for
SPL
The currently-selected detector
Elapsed measurement time, shown as mm:ss.ss,
hh:mm:ss or hhhhh:mm
Overall time weighted average (L
eq
in this case)
Time-weighted average (TWA) descriptor for
the overall measurement
Overall sound exposure level (SEL)
Overall exchange rate
Summary of Contents for System 824
Page 1: ...Model 824 Precision Sound Level Meter Real Time Analyzer Reference Manual...
Page 2: ......
Page 3: ...I824 01 Rev P Technical Reference Manual Larson Davis Model 824...
Page 58: ...2 18 824 Reference Manual 9 29 09...
Page 120: ...4 24 824 Reference Manual 9 29 09...
Page 194: ...5 74 824 Reference Manual 9 29 09...
Page 284: ...7 80 824 Reference Manual 9 29 09...
Page 312: ...8 28 824 Reference Manual 9 29 09...
Page 330: ...9 18 824 Reference Manual 9 29 09...
Page 366: ...10 36 824 Reference Manual 9 29 09...
Page 460: ...A 4 824 Reference Manual 9 29 09 shown below Both versions work properly with the Model 824...
Page 538: ...A 82 824 Reference Manual 9 29 09...
Page 546: ...B 8 824 Reference Manual 9 29 09...
Page 569: ...9 29 09 C 23 Windscreen Response with Respect to No Windscreen...
Page 596: ...C 50 824 Reference Manual 9 29 09...
Page 630: ...E 10 824 Reference Manual 9 29 09...
Page 638: ...F 8 824 Reference Manual 9 29 09...
Page 648: ...G 10 824 Reference Manual 9 29 09...
Page 672: ...iv xxiv Index Model 831 Technical Reference Manual...