Simrad ST90 - Reducing Noise and Reverberation with the AGC (Automatic Gain Control) Function

457420/A
79
NotethatGain,TVG(TimeV ariedGain)andDisplayGainarenotlters,butincluded
onlytoillustratethecomplete"signalpath".
Relatedtopics
Improvingtherecognitionofshandschoolsusingreceiverlters,page78
ReducingnoiseandreverberationwiththeAGC(AutomaticGainControl)function,page79
ReducingpropellernoiseandinterferencewiththeNoiseFilter,page81
ReducingbottomandsurfacereverberationwiththeRCG(ReverberationControlledGain)
function,page82
ReducingnoiseandfalseechoeswiththePing-PingFilter,page84
Adjustingtheintensityoftheechopresentations,page86
ReducingnoiseandreverberationwiththeAGC(Automatic
GainControl)function
Identifyingechoesfromshandschoolscanoftenbechallengingwhentheyarehidden
bynoiseandreverberation.Whensonarconditionsarepoor,effectivetuningofthelters
intheST90maybenecessarytoachieveasatisfactoryresult.AutomaticGainControl
(AGC)isoneofthetoolsprovidedbytheST90toremovenoiseandreverberationfromthe
echopresentation.
Context
TheAGC(AutomaticGainControl)functionrunsanautomaticanalysisoftheechostrength.
BasedonthisanalysistheST90maintainsaproperdynamicrangebasedonallthecurrent
echovalues.Thisisdonebyautomaticallyreducingthegainifyouhavereverberationand
noise,orincreasingthegainiftheacousticalconditionspermitit.
Operatingprocedures