11
NOISE REJECT and ASP
(Advanced Signal Processing)
The ASP
(Advanced Signal Processing) feature is a noise
rejection system built into the sonar unit. It constantly
evaluates the effects of boat speed, water conditions and
electrical interference and automatically gives you the best
display possible under most conditions.
ASP is an effective tool in combating noise. In sonar terms, noise is any
undesired signal. It is caused by electrical and mechanical sources such
as bilge pumps, engine ignition systems and wiring, air bubbles passing
over the face of the transducer, even vibration from the engine. In all
cases, noise can produce unwanted marks on the display.
The ASP noise rejection feature is especially useful because it typically
lets you operate the boat at all speeds without adjusting the sensitivity
or other controls.
The ASP feature has three settings — Off, Low and High. When first
turned on, noise rejection is set on low. If you have high noise levels, try
using the high ASP setting. However, if you are having trouble with
noise, we suggest that you take steps to find the interference source and
fix it, rather than continually using the unit with the high ASP setting.
There are times when you may want to turn ASP off. This allows you to
view all incoming echoes before they are processed by the ASP feature.
To change the ASP setting, press
MENU DOWN
until
N
OISE
R
EJECT
appears. Use the up and down arrow keys to select the desired setting,
then press
PWR
to clear the menu.
DISPLAY ADJUSTMENTS
TEMPERATURE ON/OFF
This unit is capable of displaying surface water temperature when it is
connected to a transducer with built-in temp sensor. (For accessory
ordering information, look inside the back cover of this manual.)
If you have a temp sensor connected and wish to see the water temp,
press
MENU
repeatedly until the
T
EMP
menu appears. Press
UP ARROW
to turn the temperature display on or the
DOWN ARROW
to turn it off.
DEPTH UNITS OF MEASURE
This unit can show the depth in feet or meters.
To change the depth units of measure, press
MENU DOWN
until the
U
NITS
menu appears. Use the arrow keys to select
the desired unit of measure, then press the
PWR
key to clear
the menu.
Summary of Contents for LCF-1440
Page 4: ...ii Notes ...
