Norsonic NOR150, Instruction Manual

Page: 158 / 216

142 Chapter 21
Sound Intensity
Too short averaging time – Triggered if the
averaging time is less than the requirement for a
segment.
Probe not checked
- Triggered if the probe has
not been phase corrected or verified the last 24 hours.
Dynamic capability too low
Triggered if the F2 exceeds the dynamic capability
for a frequency band (F2 > Ld). Applies to F2 values
in the total scope. The warning may be avoided by a
proper phase correction and avoiding measurements
in highly reactive sound fields or extraneous noise.
Dynamic capability too low
Issued if the F2 exceeds the dynamic capability for
a frequency band (F2 > Ld). Applies to F2 values in
segments.
Negative intensity
One or more bands have negative direction intensity/
sound power on the total surface. The A-weighted
level is not valid.
Extraneous intensity
Issued if the F3-F2 exceeds 3 dB for one or more
bands.
Field not stationary
Issued if the temporal variability indicator F1 exceeds
0.6 for a band.
Inadequate number of positions
Issued if N > C*F2, where N is the number of positions
and C is constant depedent on frequency and selected
accuracy. In practice, the deviations from segment to
segment is to large, and more positions are needed to
fulfill the requirements of the standard.
Weighted sum range not compliant
Issued if Weighted sum freq. range is not set to exactly
50 Hz to 6.3 kHz.
Frequency range not compliant
Issued if the filter bandwidth is not equal to or
exceeeding the range 31.5 Hz to 10 kHz..
High level outside A-total
Indicates that a frequency band outside Weighted sum
freq. range is less than 6 dB below the total A-weighted
value when the band is A-weighted.
Too short averaging time
Issued if the measurement duration is not satisfying
B*T
≥ 400. B is the bandwidth of the lowest frequency
band on the weighted sum freq. range [Hz]. T is the
measurement duration [sec].