Norsonic NOR150, Инструкция по эксплуатации

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18 Chapter 4
The measurement functions available
The term Multispectrum is octave or third octave
values acquired in the time profile. One spectrum is
measured per profile period. This requires a relatively
high amount of calculation power due to the amount
of data calculated. The highest work load however is
triggered audio recording.
Statistics. There are eight percentiles available. The
class width is 0.2 dB over the entire 130 dB range. Each
of the eight percentiles can be set to any value between
0,1% to 99,9%.
The statistical distribution calculation applies to the
spectral weighting networks (A, Z and C) as well as all
the individual filter bands (if applicable). The statistics
is also calculated for each period of the time profile,
providing the time profile resolution is set to one minute
or more in the profile A.
The graphical back-erase feature (Figure 4.5), which
deletes the most recent seconds ( 0-20 sec back
erase) of acquired global data prior to a pause upon
resuming, updates the statistics buffers as well as
maintain consistency.
For the statistical sampling the user can select either
Fast or Slow time constant, irrespective of what time
constant(s) the frequency analysis as such employs.
Figure 4.5