Svantek SV 973, User Manual

Page: 65 / 212

SVAN 973 User Manual
65
10 1/1-OCTAVE AND 1/3-OCTAVE ANALYSER
The instrument operates as a real time 1/1-octave or 1/3-octave analyser 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 9 center frequencies from 8 kHz down to 31.5 Hz; in base ten
system) and 1/3-octave (with 28 center frequencies from 10 kHz down to 20 Hz; in base ten system)
digital pass-band filters are working in real-time with weighting filters (
Z , A , B or C ) selected in the
Spectrum screen ( 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.
The read-out of the spectrum value can be done using a
vertical cursor.
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.
10.1 S
ELECTING
1/1 O
CTAVE OR
1/3 O
CTAVE FUNCTION
To select the 1/1-octave or 1/3-octave analysis function,
open the Meas. Funct screen, select the 1/1 Octave or
1/3 Octave position and press <Enter> .
<ENT>
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 available permanently.
10.2 C
ONFIGURING
1/1-
OR
1/3-
OCTAVE ANALYSER
10.2.1 General measurement settings for 1/1- or 1/3-octave analysis
– General Settings
Execution of the 1/1-octave or 1/3-octave analysis depends on certain set of parameters, configured in
the Measurement section.
The averaging of results for each spectrum band is performed during the
Integration Period and is repeated the Repetition Cycles times.
Both parameters are defined in the General Settings list.
Note: The measurement range for the 1/1 or 1/3-octave analysis is the same as for the
Level Meter function (see Chapter
4.6 ).