11 1/1 AND 1/3 OCTAVE ANALYSER
The instrument operates as a real time 1/1 Octave or 1/3 Octave analyser (RTA) in a very similar way
to the Level Meter. Moreover, 1/1 Octave or 1/3 Octave analysis is performed in parallel with the Level
Meter measurements. All 1/1-octave (with 10 centre frequencies from 16 kHz down to 31.5 Hz; in base
two system) and 1/3-octave (with 31 centre frequencies from 20 kHz down to 20 Hz; in base two system)
digital pass-band filters are working in real-time with weighting filters (Z, A, B or C) selected in the
Spectrum window (path: Menu / Measurement / Spectrum / Filter) and the linear LEQ detector. This
enables a spectrum pre-weighting with one of the selected broadband frequency curves if required for
the application such as the provision of hearing protectors during the control of high workplace noise
levels.
Note: TOTAL LEQ results are measured with their own weighting filters (A, C, Z) regardless
of settings made in profiles for Level Meter calculations. Spectra are always linearly averaged.
Thus, TOTAL values from 1/1 Octave or 1/3 Octave analysis can be different from those
obtained for profiles (if the LEQ Integration was set as Exponential).
For each octave or one-third octave band, the RMS, Min or Max result is
calculated and presented as a bar on the spectrum plot. Results of 1/1 Octave
and 1/3 Octave analysis (spectra) can be examined by the user on a display in
the Spectrum presentation mode.
Besides results for bands three Total values are measured and displayed as an
additional three bars on the spectrum plot. Parameters for Total values (e.g.
filters) are set by default and cannot be changed.
The read-out of the spectrum value can be done using a vertical cursor.
11.1 SELECTION OF THE 1/1 OCTAVE OR 1/3 OCTAVE FUNCTION
To select the 1/1 Octave or 1/3 Octave analysis function,
open the Meas. Funct window, select the 1/1 Octave or
1/3 Octave position and press <Enter>.
Note: The 1/1 Octave and 1/3 Octave functions are optional and should be unlocked by
entering the activation code in the text editor screen, which is opened after first attempt to
select them. Once unlocked these options will be ready to use permanently.
Note: It is not possible to change the current function during a running measurement.
In this case, the instrument displays for about 2 seconds the message: “Measurement in
Progress”. To change the current function, the measurement must be stopped!
11.2 CONFIGURING THE 1/1 OR 1/3 OCTAVE ANALYSER
11.2.1 General measurement settings for the 1/1 and 1/3 octave analysis –
General Settings
Execution of 1/1 Octave or 1/3 Octave analysis depends on certain set of parameters, configured in the
Measurement section.
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