Specifications

SimradSH90
RCG(ReverberationControlledGain)
TheRCGfunctionadjustthepicturetominimizeinuencefrom
bottomandsurfacereverberation.
Thestrengthoftheltercanbeselectedinthemenu.With
maximumstrengthisselected,theRCGwilleffectivelyreduce
thebottominshallowwater,whilevariationsonthebottom
willbedisplayed.Notethatscatteredshcanbeperceivedas
reverberation.TheRCGltermustthereforebeusedwithcareif
scatteredschoolsaretobedetected.
Ping-to-pinglter
TheeSimradSH90isequippedwithaping-to-pinglter(PP
Filter)toprovideacleanandsteadypresentationbyreducingthe
interferenceandnoise.Thisltercomparestheechoesfroma
selectedamountoftransmissions(pings),andanechohastobe
presentintheselectedamountofpingsinordertobepresented
onthedisplay.
Notethatinroughseas,whenthebeameasilycanmissthetarget
inseveralpings,thePPFiltermustbeusedwithcare.
TVG(TimeVariableGain)
TheTimeV ariableGain(TVG)functioncontrolsthegainof
thereceiversothataschoolwithagivensizeanddensityis
presentedwithapproximatelythesamestrengthonthedisplay,
insidetheregulatedTVGrange.Thiscanalsobeseenasalter,
becauseitreducesthenoiseclosetothevessel.Theregulated
strengthoftheTVGcanbeselectedinthemenu.
Noiselter
Thenoiselterisdesignedtoremoveunwantedacousticnoise
fromthesonarpicture.Itwillreducetheinterferencefromother
acousticsystems(sonarsandechosounders)onyourownvessel
andfromothervesselsinthevicinity.Itwillalsosuppressthe
noisefromyourownpropellersandfromothersimilarnoise
sources.
Transmission
ThetransmissioniscontrolledbytheProcessorUnit.The
parametersyouhavechosenareused.
Thereare480separatetransmittersintheunitdistributedon
sixteentransceivercircuitboards.
Eachtransmitterisindividuallyaddressedandcontrolledfrom
thesignalprocessor.Thecontrolledparametersincludepower
outputandtimedelayforeachtransducerelementinorderto
formabeamwiththeselectedtiltangle.
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