Norsonic nor118, Instruction Manual

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4 Chapter 1
Introducing the Nor118
5 Norsonic Nor118
User Guide
We made them parallel right away, because you have
already told us how important real time frequency analysis
is to many of you.
Octave band or third-octave band measurements – the
choice is yours, depending on how you prefer to configure
your Nor118.
e octave band measurements span the range 8 Hz
to 16 kHz, while an upgrade to option 3 will provide
you with third-octave band measurements in the range
6.3 Hz to 20 kHz.
The two bandwidths share the type of functions
measured. In a single frequency analysis the Nor118
measures:
•  e Instantaneous Sound Pressure Level
• 
MAX
e Maximum Sound Pressure Level
• 
MIN
e Minimum Sound Pressure Level
• 
eq
e Integrated Equivalent SPL
• 
E
e Sound Exposure Level
While the measurement is running the instantaneous 
is available for inspection, but as soon as the measurement
is terminated the  becomes meaningless and therefore
not listed in the result tables.
If your Nor118 is equipped with parallel time constants
(option 5) the list of functions measured simultaneously
can be expanded to include functions with ,  and  time
constants at the same time.
e frequency bands measured are all visible in the
display with no need for horizontal scrolling. e f-t key
lets you enter and exit the spectrum display.
Furthermore, the instrument measures the full fre-
quency range – every time! Given the high dynamic range
(120 dB), which eliminates the need for adjusting the gain,
there is very little to set up before a frequency analysis can
be made – successfully!
e measured functions are also available in tabulated
form as numerical values. By pressing the  key before,
during or after a measurement you have instant access
to the numerical version. Another push on the key will
restore the graphical display.
Frequency band statistics.
Adding option 4 to your
Nor118 will expand your frequency analysis to even cal-
culate the statistical level distribution for each frequency
band measured! In addition statistics will be calculated
for the two spectral weighting networks employed (- and
- or -weighting). e class width is always 0.2 dB to
ensure sufficient resolution and the results are presented
in the form of eight percentiles.
One of these percentiles is subject to user-definition and
can be set to anything from 0.1% to 99.9%, both extremes
included. Note that you don’t have to define the percentile
prior to the measurement. You may redefine the percentile
as many times as you like – even after the measurement!
For every frequency band measured!
However, once you store the measurement in the
instrument’s memory, only the selected percentiles will
be available to keep the amount of data lower.
The fixed percentiles.
e fixed percentile levels offered
by option 4 are 1.0%, 5.0%, 10.0%, 50%, 90%, 95% and
99%.
For the statistical sampling the instrument makes use of
the  time constant, irrespective of what time constant(s)
the frequency analysis as such employs.