Installation manual

Table Of Contents
Basictheory
WhenyouchoosetheTVGsettingyoucaneitherswitchitoff,or
choosea“XlogR”value.Thedifferentsettingsdeterminehow
muchgainthesonarwilluseastimeelapsesalongtheX-axis.A
highervaluefor“X”willmaketheangle(C)steeper.
WhatisAGC?
AGCmeansAutomaticGainControl.TheAGCwill
automaticallyscalethereceivedechodatatomaintainaproper
dynamicrangebasedonalltheincomingechovalues.Inaddition
toOff,thestrengthoftheltercanbesettothreedifferentlevels.
WhatisthePPFilter?
PPFiltermeansPing-to-Pinglter.Whenthisfunctionis
activated,thesonarwillcomparetheechoesfromonepingwith
theechoesfromthenextpings.Ifanechoispresentattherst
ping,butthendisappearsatthenext,thesonarwillinterpretthis
asnoiseandreverberation,andsuppressit.
IfyouchoosesettingWeak,thesonarwillonlycomparetwo
consecutivepings.IfyouchoosesettingsMediumorStrongthe
sonarwillcomparefourandeightpingsrespectively.
Aboutpulseformandlength
OntheSH90sonar,youcantransmitsoundmodulatedas
FM
CW
FMmeansfrequencymodulated,whichmeansthatthefrequency
ofthetransmittedpulseischangedduringthetransmission.In
mostcasesthismethodwillprovidebetterechopresentationand
stability,andyouwillavoidexcessivenoiseandreverberation.
CWmeanscontinuouswave,whichmeansthatthetransmission
frequencyisxedduringtheentirepulse.WhenyouuseCW
transmissionyoucanchoosethelengthofthepulses.Inasearch
phaseundergoodconditions,youshouldtrysettingLong.Ifthe
conditionsworsen,trytoshortenthepulselength.Thiswillmake
iteasiertodistinguishthevariousechoes,andthereverberation
willbereduced.
ThedefaultsettingontheSH90sonarisFMAuto.Inthis
transmissionmode,thesonarwillautomaticallychoosethe
optimalpulselengthforthecurrentrange.
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