NorthStar 972 Quickstart Manual And Reference Manual page 119

Adjusting the signal level (weak
echoes)
As with the Clutter key, the Signal level
key controls the appearance of low level
noise in the picture. Whereas clutter
compresses or expands the available colors
to fit the desired signal range, Signal Level
completely removes the weaker colors and
their echoes.
To adjust the signal level:
Reference Manual Revision B
Clutter
2. Press .
3. Press the cursor pad up or down to adjust the
clutter, or use the keypad to manually enter
the desired clutter value. The available set-
tings range from zero (shows all echoes) to
nine (suppresses many echoes).
Return
4. Press to go back to the Echo
Sounder screen.
1. On the Echo Sounder screen, press
Signal level
2. Press .
3. Press the cursor pad up or down to remove
the weaker color levels from the picture, or
use the keypad to manually enter the desired
signal level.
The available settings range from
5
mum) to (maximum). For example, if you
select a signal level of
0 3
through are all displayed using the
same color as the background.
Return
4. Press to go back to the Echo
Sounder screen.
Suppressing interference (the noise
limiter)
The noise limiter reduces the adverse
effects of interference caused by other
nearby echo sounders or electronic
devices. However, the noise limiter may
cause some very weak echoes to be made
smaller or be entirely eliminated, since it
removes any echoes that aren't sustained
for at least two pings.
To turn on the noise limiter:
1. At the Echo Sounder screen, press
2. Press
3. Press the
Selecting the color bar (hue) and
white level
Picture The color bar displayed at the extreme left
.
of the
of colors used to display various echo
strengths. Weaker echoes are displayed
with colors near the bottom of the scale,
and stronger echoes are displayed with
colors near the top.
1
(mini-
You can choose any one of nine palettes of
3
, echo strengths of
colors to represent the echo strengths from
weakest to strongest.
•
Noise
to turn the limiter on or off.
Return
key to go back to the Echo
Sounder screen.
screen shows the range
Echo Sounder
Color bar #1 is the one most often
used.
Reference section 7 — Echo sounding
The picture menu
Picture
.
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