Simrad PI44 C, Руководство оператора

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Simrad PI44
178
850-165085 / Rev.B
Expansion window : The PI44 provides bottom expansion and
zoom functions. When one of these is enabled, you can control
the depth range in the expanded window using this parameter.
To enable the bottom expansion function, press the
B-LCK
button on the keypad. To enable the zoom function, press the
ZOOM button. To disable both, press the STND or SHIFT
buttons. You can also access this parameter in the Graphic
setup .
TVG (Time Varying Gain): The PI44 provides a TVG function
to enhance the echoes from deeper waters. You can switch the
TVG to OFF (not recommened), or select either Special (40 log
R) or Normal (20 log R) setting, depending on your preferences.
For all normal operation, leave it at Normal. Try Special if you
are looking for echoes close to the seabed in deeper waters.
Ping to ping filter : This function employs a filter which
compares the echo information from one ping with the
information from the previous ping. This will “clean up” the
echogram by removing random noise spikes and interference
with no correlation with the previous echo. The function will
thus make the echoes appear more stable. You can switch this
filter on or off.
Signal threshold : This is an on/off function. When activated, it
will remove the weakest echoes from the screen. The threshold
level is automatic. Activate with caution, as it may remove
small fish or other weak unidentified echoes from the
presentation.
Colour threshold : This function allows you to choose the
number of colours to use for echogram presentation. By
switching this filter on and selecting a colour in the box, all
echo colours “below” the chosen colour will not be shown in the
echogram. You can thus regard this as an “echo threshold”
which will remove the weakest echoes.
Depth grid : When this function is enabled, thin horisontal depth
lines will be added to the echogram to easier identify the depth
intervals. When you operate with a graphic display, this function
can also be switched on and off in the
Graphic setup.
Transmit pulse length: This parameter allows you to choose
the length of the echo sounder pulse transmissions. You can
choose OFF (to observe the ambient sea noise), SHORT,
MEDIUM, LONG or AUTO. In most cases, select AUTO. The
PI44 will then automatically choose the pulse length depending
on your current depth range. If you choose to try a manual
mode, try long pulse lengths when you operate in deeper waters,
and shorter pulses with higher frequency in shallower waters.