Larson Davis SoundAdvisor 831C Reference Manual page 154

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FIGURE 18-13 Display Elements on the Live Tonality Tab (ISO/PAS 20065)
1.
Tone indicator (green vertical bar)
2.
Critical Bandwidth (green horizontal bar)
3.
Harmonic Cursors (orange vertical lines)
4.
Noise Regression indicator (red line)
5.
As on other screens, press the left or right
46
buttons (
) to advance the Manual cursor
and navigate tones in the graph. Be sure the
cursor-type is set to Manual to navigate tones.
6.
ΔL Audibility: the difference between the
tone level and the masking threshold; L
Energy mean value of all narrow band levels
in a critical band. L
T
the narrow-band level with the tone
frequency of the spectral line (
band level; Uncertainty: The extended
uncertainty as described in the ISO/PAS 20065
standard.
7.
As on other screens, press the up or down
82
buttons (
graph.
SoundAdvisor Model 831C
FIGURE 18-12
FFT History Tab Displays a Vibration Record
1.
The History tab is displaying record 1
of 2 total.
2.
Press the up and down buttons
82
( ) to zoom in and out of
the graph.
3.
Press the left and right buttons
46
( )to move from one record to
another.
Viewing Data on the Live Tonality Tab (ISO/PAS 20056)
This section shows the 831C display when ISO/PAS 20065 is chosen in the setup. With the
cursor over a tone in the graph, the following details display for each tone: ΔL Audibility, Ls,
LT, LG, Tone Count. For more detail on these terms, refer to the standard.
:
S
: the energy summation of
f
T), L : Critical
G
) to Zoom in or out on the
Live Data On the Tonality Tab (ISO 1996-2 Tonality)
In the following example, the ISO 1996-2 standard was chosen in the measurement setup.
For this standard, the 831C Tonality tab displays critical bandwidths, tone indicators, and
regression noise. After the measurement is complete, you can navigate the Tonality tab
2.
1.
2.
3.
4.
5.
6.
7.
Making the FFT Measurement
1.
3.
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