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When the signal is relatively high, the additional noises must stem
from a source of interference which has a negative effect on the
measuring result.
Noise suppression ensures that correlation (averaging) only takes
place when the signals are in a certain level range (volume). If
the signals are outside of the level range, the measurement will
be discontinued.
The level range is limited by the lower threshold and the upper
threshold. These thresholds are shown for signals 1 and 2 as
horizontal lines on the far left / far right of the display when the
measurement is taking place. The level range is always reset
when
starting
the measurement. The correlator uses the level
values measured at the start as a point of reference.
a) automatic
This setting is suitable for achieving good results in all standard
cases.
After a certain time, the level range is automatically raised slowly
if the current level values are permanently over the level range.
In the same way, the level range is lowered if the current level
values are permanently below the level range.
b) manual (default setting)
This setting is recommended if you want to work with maximum
noise suppression and have maximum individual influence on
the measurement.
If the measurement is interrupted for too long because the noise
is too loud, the level range can be manually raised by pressing
“continue” and thus made less sensitive. The measurement will
continue as the user ignores a certain amount of interference
noise.
Once the current level values fall below the level range an auto-
matic adjustment takes place and the correlator becomes more
sensitive to interference noise.
c) off
This setting should only be selected if the constantly heavily fluc
-
tuating signals mean that the measurement is often interrupted
and correlation would not be possible otherwise.
Noise suppression is disabled. It is accepted that interference
noise occasionally masks the leak noise.
