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ASP and Surface Clarity Control
Noise, in electronic terms, is any undesired signal. Noise shows on the
display as random patterns of dots or lines. In severe cases, it can
completely cover the screen with black dots or lines, obscuring target and
bottom echoes. It’s caused by mechanical and electrical sources such as
bilge pumps, engine ignition systems and wiring, air bubbles passing over
the transducer’s face, even engine vibration.
This unit has an efficient noise rejection system called Advanced Signal
Processing or ASP. Noise signals are effectively reduced or eliminated
with this feature. ASP constantly evaluates the effects of boat speed, water
conditions, and interference, rejecting signals it recognizes as noise, and
letting target and bottom echoes pass.
Surface Clarity Control acts only on interference near the surface. This
feature reduces the “clutter” or random signals seen on and near the top
of the display. This noise is caused by many things including tiny plant and
animal life, wave action, and boat wakes.
When the unit is first turned on, or after it’s reset, both ASP and Surface
Clarity Control are automatically enabled. Both features are adjustable or
can be turned completely off, if desired.
To adjust ASP, press the MENU key, then press the key adjacent to the
“Sonar Controls” label. Now press the key next to the “More” label until the
ASP menu appears as shown at the top of the next page. You’ll notice it has
two levels: Low and High. To change the ASP level, simply press the key
next to the arrow on the ASP menu until the check mark lands on the
desired level. When you’re finished, press the CLR key.
To adjust the Surface Clarity
Control, press the MENU key,
then press the key adjacent to
the “Sonar Controls” label. Now
press the key next to the “More”
label until the Surface Clarity
menu appears as shown at the
top of the next page. Press the
key next to the right arrow in the
Surface Clarity menu to in-
crease its level, press the key
adjacent to the left arrow to
