Simrad EK15 - Page 278

SimradEK15
dTargets(40logTVG)
Basically,thissettingusesthesameTVGamplicationasFish,butadditional
lteringandcompensationisimplemented.Onlyechoesdetectedandinterpretedas
singleshareshown.Theechoesarecompensatedfortheirphysicalpositioninthe
beam(beamcompensation).Thismeansthatshintheouterregionofthebeamare
adjustedtocorrectsizeeventhoughtheirechoesareweaker.
NotethatthisTargets(40logTVG)settingisonlyfunctionalwithsplitbeam
transducers.
eTargetMix(40logTVG)
Basically,thissettingusesthesameTVGamplicationasFish,butadditionalbeam
compensationisimplemented.Echoesdetectedandinterpretedassingleshare
adjustedtotheircorrectsizeaccordingtotheirphysicalpositioninthebeam.
NotethatthisTargetMix(40logTVG)settingisonlyfunctionalwithsplitbeam
transducers.
fUser(VariableTVG)
ThissettingallowsyoutodeneyourownTVGsetting.
YoucanadjusttheTVGsettingusingtheEchogramorTVGfunctions.Botharelocated
ontheActivemenu.
Becausethestrengthoftheechoeswillbecomeweakerwithincreasingdepth,theecho
sounderwillautomaticallyamplifythedeepestechoesmorethantheshallowerechoes.
Infact,thegainwillincreaseproportionaltohowlongtheechosounder“waits”forthe
echoes.WhenyouchoosetheTVGsettingyoucaneitherswitchitoff(whichwedo
NOTrecommended),oryoucanchoosesettings20logRor40logR.
Thevarioussettingscontrolthegainalgorithms,howmuchgaintobeappliedwhen
thedepthincreases.Whenyouchoosethe40logRsetting,thegainwillincreasewith
thedepthmorerapidlythanifyouchoosethe20logRsetting.Thisissimplybecause
individualshemitsmallerechoesthanaschool,andthismakesthemmoredifcultto
detect.IntheequationthecharacterRmeans“Range”.
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