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Functions and dialog boxes
Noise Filter function
The
removes unwanted acoustic noise from the display presentation. It
Noise Filter
reduces the interference from other acoustic systems (sonars and echo sounders), as well
as the noise from the propellers.
How to open
You open this function from the
menu.
Active
Description
The
is used to minimize the interference from other acoustics systems (sonars
Noise Filter
and echo sounders) on your own and/or other vessels. The filter also suppresses noise
from your propellers, and from other similar noise sources. The
is very
Noise Filter
effective if you are bothered by strong noise or interference, especially from your own
vessel, or even from other vessels operating near you.
The four filter settings are used to control the "efficiency" of the filter. To disable the
filter, set it to Off.
Tip
Use weak filtering - or turn the filter off - if you have strong echoes on short ranges. The
filter may then be too powerful, and distort the echo presentation.
Select the middle of the button to open a small menu with the available options. Select
the left side of the button to select a "lower"' menu choice. Select the right side of the
button to select a "higher"' menu choice.
Additional information for the technically minded:
The filtering is done by overriding the automatic function for the preamplifiers. The
number of amplifier stages used is a function of range instead of signal level. There is
a total of six amplifier stages. By forcing the SN90 system to use (for example) three
amplifier stages at a certain distance, interference will be clipped at this specific range.
This is better than suppressing all other echoes at the same range.
The filters in the SN90 system are implemented in "series". The noise filtering is done
early in the receiver process.
485
381294/E
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