77
SV106A User Manual
10. 1/1 AND 1/3 OCTAVE ANALYSER
The instrument operates as the
1/1 Octave
or
1/3 Octave
analyser in a very similar way as in the
Level Meter
mode and, in addition, 1/1-octave or 1/3-octave
analysis is performed in parallel with the
Level Meter
measurements. All 1/1-octaves (with the centre frequencies from 2 kHz down to 0.5 Hz; in base two system)
and 1/3-octaves (with the centre frequencies from 2.50 kHz down to 0.40 Hz; in base two system) digital pass-
band filters work in real-time with the
HP
weighting filter (type 1 according to the IEC 61672-1 standard; the
filter characteristics are given in Appendix D) and the linear RMS detector.
The results of
1/1 Octave
and
1/3 Octave
analysis (also called spectrum analysis)
can be examined by the user on a display
in the
Spectrum
presentation mode. The
availability of this mode can be controlled
by the user (
path: <Menu> / Display /
Display Modes
).
..
1/1 Octave
and
1/3 Octave
spectrum for all centre frequencies of pass-band filters and with three
Total Values
, measured with weighting filters selected by the user,
are presented in the
Spectrum
mode.
10.1. Selection of 1/1 Octave or 1/3 Octave analysis mode
To select the
1/1 Octave
or
1/3 Octave
analysis mode the user has to enter the
Function
list by pressing the
<Menu>
push-button,
then
select
the
Measurement Function
text 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 it. Once
unlocked, this option will be ready to use permanently.
Note: It is not possible to change the current function while a measurement is taking place.
In this case the instrument displays for about 2 seconds the text
”Measurement in Progress”. In
order to change the current measurement function, the measurement must be stopped!
10.2.
Setting the parameters of 1/1 Octave and 1/3 Octave analysis
The execution of
1/1 Octave
or
1/3 Octave
analysis depends on settings of the
General Settings
list:
Measure Period
and
Repetition No.
. Other parameters are set up by default: weighing filter (
HP
), frequency
range (from 0.5 Hz up to 2 kHz for 1/1-octave analysis and from 0.40 Hz up to 2.50 kHz for 1/3-octave analysis)
and measurement range (
126 m/s
2
). In every 1/1 octave or 1/3 octave pass band the
RMS
result is measured.
Additionally to the pass band RMS results, three Total values are measured during 1/1 and 1/3 octave analysis.
Total values parameters (weighting filter, type of integration filer for acceleration, velocity or displacement
results and additional calibration factor) are setting up in the
Total Values
window (
path: <Menu> / Display /
Spectrum Display Setup
).
The output of a selected
1/1 Octave
or
1/3 Octave
filter can be also used as a triggering signal for different
trigger applications: triggering the logger, triggering the event recording, triggering the wave recording and
alarms.
