Emodumeter Selections
12 www.ndtjames.com
1024 points
2048 points
80 kHz
78.1 Hz
39.1 Hz
40 kHz
39.1 Hz
19.5 Hz
20 kHz
19.5 Hz
9.8 Hz
10 kHz
9.8 Hz
4.9 Hz
Figure 6: Frequency resolution for each combination of sampling frequency and
number of points
Maximum
Frequency (kHz)
80 kHz
40
40 kHz
20
20 kHz
10
10 kHz
5
Figure 7: Maximum frequency (kHz) for different sampling frequency selections
The selection of sampling frequency and number of points shall
allow the user to identify frequencies with the needed accuracy and
in the required range of frequencies.
Trigger Level
The Trigger level is adjusted in percentages: 10%, 20%, 30%, 40%,
50%, 60%, 70%, 80%, and 90%. Pressing the escape keys the
system returns to the main menu, so test can be started. Lower
trigger level should be used when testing small samples. The
Trigger Level should be set to a level that the system records the
signal just after the impact and not before. When using low trigger
levels, environmental noise could trigger the system. Trigger level
should be increased because the system should only be activated
by the actual impact of the steel ball.
