Koden CVS-702D, Основное руководство по эксплуатации

Страница: 90 / 144

Chapter 2 Basic operation CVS-702D
2-62 0093107022-02
To manually correct TVG:
The reflected signals of echo sounder have less sensitivity due to attenuation, as depth is
deeper.
In the TVG correction for CVS-702D, a reference point of depth for correction is to be
determined. This reference point is [TVG Depth].
Reflected signals from a shallower depth than this reference point are corrected to have the
same sensitivity as that of the reference point.
In [Strength], the amount of change in this correction is set. The larger the value of [Strength]
becomes, the larger the amount of change becomes. (See the figure below)
For reflected signals from shallower positions, amount of correction becomes larger. When
[Strength] is set large, the correction amount for shallow depth may seem too much. In such
cases, if the [Adjust] is set at the depth at which correction seems too much, the correction
amount at shallower depth than the depth becomes the same as the correction amount at the
starting position, and can set off the over correction.
Setting should be performed in combination of the items above.
Adjustment of TVG strength of manual TVG:
[TVG Strength] decides the amount of change for TVG correction. The larger the value of
[TVG Strength] is, the bigger the amount of change is.
The far left side line is Strength 1 and the far right side line is Strength 50 in the graph.
Change in TVG correction by change in strength
(Depth 140 m/Adjust 1 m)
0
20
40
60
80
100
120
140
0 10 20 30 40 50
TVG correction (-dB)
Depth (m)
1
5
10
15
20
25
30
35
40
45
50