NorthStar Navigation NorthStar 491 manual Suppressing interference the noise limiter

Models: NorthStar 491

1 76
Download 76 pages 27.45 Kb
Page 35
Image 35

desired signal range, Signal Level completely removes the weaker colors and their echoes.

To adjust the signal level:

1.On the ECHO screen, press PICTURE.

2.On the PICTURE screen, press SIGNAL LEVEL.

3.At the SIGNAL LEVEL window, press the CURSOR PAD up or down to remove the weaker color levels from the picture, or use the KEYPAD to manually enter the desired signal level.

The available settings range from 1 (minimum) to 5 (max- imum). For example, if you select a signal level of 3, echo strengths of 0 through 3 are all displayed using the same color.

4.Press RETURN to go back to the ECHO screen.

Suppressing interference (the noise limiter)

The noise limiter reduces the adverse effects of interference from other nearby echo sounders or electronic devices. however, the noise limiter may cause some very weak echoes to be made smaller or entirely eliminated, since it removes any echoes that aren’t sustained for at least two pings.

To turn on the noise limiter:

1.At the ECHO screen, press PICTURE.

2.At the PICTURE screen, press NOISE LIMITER.

3.At the NOISE LIMITER window, press the CURSOR PAD up to turn the noise limiter on (or press NOISE LIMITER again).

4.Press the RETURN key to go back to the ECHO screen.

Turning the noise limiter on changes a portion of the

PICTURE key tab from green to yellow, as a reminder.

491 Echo Sounder Operations Manual

Page 31

Page 35
Image 35
NorthStar Navigation NorthStar 491 manual Suppressing interference the noise limiter