Kongsberg MS1000 Operator's Manual page 38

Kongsberg Mesotech Ltd. operator manuals / MS1000
Select Low to set the upper limit on TVG gain lower than default
TVG Type
Select 20log to use TVG A factor = 20
Select 30log to use TVG A factor = 30
Select 40log to use TVG A factor = 40
Select Test to select a simple ramped TVG curve.
Select User to allow a custom TVG curve to be defined.
TVG Curve
The TVG curve uses three different colored lines to show the current settings
graphically.
The solid green line shows the current TVG curve.
The dashed red line shows the upper limit for the TVG curve.
The position of the yellow line can be adjusted up or down with the slider control to
the left of the graph. The range and gain at the intersection of the yellow and green
lines is shown in the Range-Gain box.
The Settings controls allow a custom TVG curve to be defined. Four adjustable
factors are used to set the gain curve:
A factor represents spreading loss,
B factor represents one way absorption loss,
C factor represents a base or starting gain level.
L factor limits the maximum gain to reasonable levels
The equation used is:
Gain = A log(R) + 2BR + C
Gain = L, if Gain > L
Where R is proportional to time since transmission start (range)
Legacy TVG
The TVG is calculated based on the user selected frequency. This will be different
from the legacy hard-coded TVG. If the user prefer the sonar image acquired with
the legacy TVG, check this option, the legacy TVG will apply to the standard legacy
frequencies, such as 330kHz, 675kHz.
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© 2021 ... Kongsberg Mesotech Ltd. Document No. 901-10017002 Issue 6.54