FLIR RAYMARINE E125 - Time Varied Gain (TVG)

Adjusting the Surface lter
Adjusting the Surface lter settings can improve the
sonar image.
From the Sensitivity Settings menu:
1. Select Surface Filter.
2. Adjust the slider control to the required value, or
3. Select Auto to allow the system to automatically
adjust the Surface Filter for current conditions.
Time Varied Gain (TVG)
The Time Varied Gain (TVG) setting controls the
amount of attenuation applied throughout the water
column, which provides a balance of shallow water
returns (where echoes are strong) against deep
water returns (where echoes are weak) so that
targets of the same size produce echoes of the
similar size regardless of target depth. The TVG
setting can be manually set from 0% to 100% or set
to automatic.
• A higher TVG setting will produce weaker targets /
less clutter on-screen.
• A lower TVG setting will produce stronger targets /
more clutter on-screen.
Note: TVG values between 0% and 30% represent
top out mode control, values between 31% and
100% represent TVG control.
31% TVG 100% TVG Auto TVG
Note: TVG has no effect in simulator mode
however top out mode (0% to 30%) does.
Top out mode
Top out mode is a digital lter that is combined with
the TVG control. The top out mode lter reduces
noise and clutter from the top portion of the sonar
beam.
Top out mode is active when TVG values are
between 0% and 30%. TVG values between 31%
and 100% represent actual TVG control.
0% TVG 30% TVG
Setting TVG to Automatic
The TVG setting can be set to automatic by following
the steps below.
From the Sonar application:
1. Select Menu.
2. Select Sensitivity Settings.
3. Select TVG.
The TVG slider bar control is displayed.
4. Select Auto so that a tick is placed in the auto
box.
Auto TVG mode
When TVG is set to automatic 3 auto TVG modes
are available, depending on sonar module in use.
The auto TVG modes available are as follows:
• Low
• Medium
• High
Auto TVG modes are only available on Legacy sonar
modules and Traditional internal sonar modules.
Selecting an auto TVG mode
Follow the steps below to select an Auto TVG mode.
From the Sonar application, with TVG set to Auto:
1. Select Menu.
2. Select Sensitivity Settings.
3. Select Auto TVG.
4. Select the required setting: Low, Medium or High.
Manually adjusting TVG
From the Sonar application menu:
1. Select Sensitivity Settings.
2. Select TVG.
The TVG slider bar control is displayed.
3. Adjust the slider bar control to the required
setting.
Values between 31% and 100% represent TVG
control.
4. Select Back or OK to close slider bar control.
Sonar (Fishnder) application
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