Larson Davis System 824, Technical Reference Manual

Page: 203 / 673

9/29/09 System 824 Virtual Instruments 6-9
Sound Exposure
The System 824 lets you set the criteria level and criterion
time for Dosimetry measurements. A 100% dose occurs if a
person is exposed to a constant sound field with a SPL equal
to the criterion level, for the criterion time or full dose hours.
The criterion level setting can take on any integer value
within the following range:
0 to 255 dB
Exposures at higher sound exposure levels than the overall
criterion level will result in a 100% dose in less time; or, if
exposure continues, the overall dose will exceed 100%.
The following are examples of the System 824 Sound
Exposure displays:
LOG and ISM Measuring Ranges
The following table presents the typical RMS detectors
measuring ranges for the LOG and ISM instruments:
Range
Frequency Weighting
A C Flat
Low Range
20–108 dB 25–108 dB 25–108 dB
Normal Range
23–128 dB 28–128 dB 30–128 dB
High Range
43–148 dB 48–148 dB 50–148 dB