3M SE-402 - Overload (OL); Pascal (Pa); Reference Pressure; Response Time (Fast “F”, Slow “S”)

Appendix B
Sound Examiner SE-400 Series
36
Overload (OL)
An overload will occur whenever the input signal exceeds the dynamic range of the instrument.
Pascal (Pa)
Unit of pressure equal to 1 Newton per square meter.
Reference pressure
The sound pressure at the threshold of human hearing, as measured under standard conditions. This generally
accepted magnitude of this pressure is 2 .00002 Pascals .
Response time (Fast “F”, Slow “S”)
Selectable time response settings used in the Sound Examiner measurements. The response time is a standardized
exponential time weighting of the input signal according to fast (F) or slow (S) time response relationships. Time
response can be described with a time constant. The time constants for fast and slow responses are 0.125 s, 1.0 s.
Figure B-2: Slow response to a tone burst
Burst duration, t (seconds)
Relative response (dB
)