Raymarine DS400 & DS500 用户手册

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页码 96
Chapter 3: Getting Started
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Note:  Menu items that are displayed in all caps followed by an ellipsis (
GAIN 
MODE..., for example) contains sub-menus. Use the trackpad keys to scroll 
through the sub-menus.
3.8 Interpreting and Adjusting the Sounder Image
The DS400/500 uses sound waves to find fish and show the bottom of a lake 
or sea. The transducer sends high-frequency sound waves into the water; 
these sound waves strike fish, the bottom, or other objects in the water and 
return as echoes. The DS400/500interprets these echoes to present an image 
of the fish and bottom.
The strength of echoes is indicated by different colors. You can use this 
information to determine the size of fish and the bottom structure. Other 
objects in the water, such as debris and air bubbles, also return echoes; these 
echoes are generally weaker than the fish or bottom echoes and produce 
background noise or clutter on the display. The digital sounder provides 
controls to reduce the background noise and to adjust the way in which 
echoes of different strengths are displayed.
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ft
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Range
Frequency
AUTOMATIC
AUTOMATIC
Scroll Speed
ON
A-Scope
OFF
GAIN MODE...
ZOOM...
AUTO FISHING
DISPLAY SET UP...
SOUNDER SET UP...
TRIP RESET...
MAIN MENU
MAIN MENU
ARROW and ENTER key-help symbols
prompting you to use Trackpad and
ENTER keys to change this menu item.
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