Furuno GP-7000F - Manual (Page 94)

10. VIDEO SOUNDER OPERATION
10-8
A-scope display
The A-SCOPE display, which can be enabled or disabled on the SOUNDER
menu, shows echoes at each transmission with amplitudes and tone proportional
to their intensities. It is useful for estimating fish specifies and seabed
composition.
50
100
0
59.6
ft
Strong echo
(bottom)
A-scope
Fish school
Ex. Single frequency display
50k
Weak echo
A-scope display
10.2 Automatic Sounder Operation
Automatic sounder operation is useful when you are preoccupied with other
tasks and do not have the time to adjust the display.
10.2.1 How the automatic sounder works
The automatic sounder function automatically selects the proper gain, range
scale and clutter suppression level according to the depth. It works as follows.
 The range changes automatically to locate the bottom on the lower half of the
screen. The range jumps to one step shallower range when the bottom
echoes reach a half way point of the full scale from the top and to one step
deeper range when they come to the lower edge of the scale.
 The gain is automatically adjusted to display the bottom echo in reddish brown
(default color arrangement).
 Clutter, which suppresses low level noise, is automatically adjusted.