Technical information

Echosoundertheory
Relatedtopics
•Changingthepulsedurationtoenhancetheverticalresolutiononpage22
•NormalOperationonpage76
Rangeselection
Foreveryfrequency(channel)youwishtopresentontheechosounderdisplay,youare
providedwithtwoechograms.
Figure18Rangeselection
A
B
C
D
(CD010217E)
AUpperechogram(surface
related)
BLowerechogram(bottom
related)
CScopeviewforupperechogram
DScopeviewforlowerechogram
Normally,theupperechogramwill
showtheentiredepthrangefrom
theseasurfaceanddowntothe
bottom,whilethelowerechogram
showsabottomexpansion.Thisis
amagnicationoftheareajustabove
andbelowthebottom.
Youarefreetochooseany
presentationyouwantinanyofthe
echograms.
Upperechogram:Pelagicor
surfacerelated
Example7StartRangeinasurfacerelatedechogram
Inasurfaceechogram,settheStartRangevalueto0meters.Thiswillmakethe
echogramstartfromtheseasurface(providedthatthetransduceroffsethasbeen
dened).SetRangetothecurrentdepthplus20meters.Theechogramwillnow
showtheareafromtheseasurfaceanddownto20meters“below”thebottom.
Thebottomcontouriseasilydetectedwhenthedepthchanges.
Example8StartRangeinasurfaceechogram
Inasurfaceechogram,settheStartRangevalueto10meters.Thiswillmakethe
echogramstartfrom10metersbelowtheseasurface(providedthatthetransducer
offsethasbeendened).SetRangetothecurrentdepthplus20meters.The
echogramwillnowshowtheareafrom10metersbelowtheseasurface,anddown
to10meters“below”thebottom.Thebottomcontouriseasilydetectedwhen
thedepthchanges.
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