Navman 8084, Инструкция по установке и эксплуатации

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NAVMAN 8120/8084 Installation and Operation Manual 43
9-6 Gain and threshold
Gain and threshold settings control the
amount of detail displayed on a sonar
window:
Gain : The gain of the sonar receiver. The
gain should be high to display good detail,
but if the gain is too high then information
from the strong bottom signal is lost and
false echoes might be displayed. There
is a separate gain setting for each sonar
frequency, 50 kHz and 200 kHz.
Threshold : Return echoes less than the
threshold are ignored. The threshold should
be as low as possible, but if the threshold is
too low, unwanted noise will be displayed.
Threshold is set as a percentage of gain. For
example, if the threshold is 50 %, then return
echoes less than 50 % of the maximum signal
are ignored. There is a separate threshold
setting for each sonar frequency, 50 kHz and
200 kHz.
The gain window
To display or change the current settings for
gain, select a sonar window and press
ENTER
.
Select
Threshold
to display the thresholds.
This window is called the gain window.
Changing mode
The Instrument has three operating modes, In
Cruising and Fishing modes, the Instrument
automatically adjusts gain and threshold for
good performance. In manual mode, you can
hand adjust the settings.
To change the mode from the Gain window,
Select
Mode
and then select
Fishing
,
Cruising
or
Manual
. When you select
Manual
, the Instrument reverts to your last
manual settings.
Changing gain and threshold
1 In the Gain window, press or to select
the setting to adjust.
2 Press or adjust the setting. The
Instrument changes to Manual mode.
Tip : Use the A-scope window to help set
gain or threshold manually (see section
10-5).