2-13
2.12 Echo averaging (EAV 1/2/3)
Remarks on the echo-averaging feature
Echo averaging is a useful feature when used properly. If used improperly, however, the
result could be disastrous.
Objective and principle of echo averaging
The main objective of echo averaging is to discriminate targets (flocks of birds, other ships,
fishing floats, etc.) hidden in sea clutter, and stably display long range targets (ship, buoy,
island, etc.) which alternately appear and disappear on the screen.
Normally, unstable echoes such as those from sea clutter and noise appear at random
positions with every rotation of the antenna. To distinguish real target echoes from clutter, the
picture is stored and averaged over successive picture frames. If an echo is solid and stable it
is shown in its actual intensity. Unstable echoes are reduced in intensity.
The following illustrates how echo averaging EAV 1/2/3 work.
Figure 2.8 Echo Averaging
OFF
Echo level
15
Echo level
15
1 2
1 2
Echo level
15
1 2
Echo level
15
1 2
No. of Scan
No. of Scan
No. of Scan
No. of Scan
FR-2115-SME-27C
EAV1
EAV2
EAV3
Summary of Contents for FR-2155
Page 1: ...MARINE RADAR MODEL FR 2155 PRINTED IN JAPAN...
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Page 65: ...3 9 Location of Parts on RP Board 14P0298 CR1 S1 Battery BT1 Flash ROM U3...
Page 80: ...3 24 Location of Parts on PFN 1 board 03P6668...
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