Controlling The Gain And Range Settings; Adjusting The Gain (Echo Sensitivity) - Kongsberg Simrad SU90 Operator's Manual

Simrad SU90 Operator Manual

Controlling the gain and range settings

Topics
Adjusting the gain (echo sensitivity), page 58
Adjusting the TVG (Time Variable Gain) setting, page 60
Adjusting the sonar range, page 60
Expanding the range within the sonar view, page 62
Adjusting the intensity of the echo presentations, page 63
Changing the tilt, page 63
Adjusting the bearing, page 65

Adjusting the gain (echo sensitivity)

Some echoes are weak while others are stronger. To compensate for this it is often
necessary to adjust the sensitivity of the SU90 system. This adjustment is commonly
referred to as gain.
Context
You can compare this gain setting with the volume control on your car radio. When
the gain is increased, the echoes will appear stronger. Weak echoes will be easier to
see. However, since you also increase the acoustic noise in the reception, the echo
presentations will also show this noise. Too much gain may therefore "distort" the
presentation.
Comparing the gain function with the volume control on your car radio is not very
accurate. In fact, the gain in the SU90 system is constant. The function is used to
Gain
adjust the sensitivity. This is done by controlling the minimum level of detection. When
you increase the gain level (more positive number), you reduce the minimum level of
detection, and thus increase the echo sensitivity.
The echo strength (A) changes with time. The minimum level of detection (B) is adjusted
up or down with the function. Increasing the with a more positive number
Gain Gain
58
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