SimradSU90
bSetRangeto2000meters
cSetNoiseltertoOff
dSetTXPowertoOff
4OpentheDisplaymenu.
aSetDisplayGainto5
5OpentheSetupmenu.
6IntheSetupmenu,clicktheTestbuttontoaccessuptheSystemTestmenu.
aSetInterpolationtoOff
Testprocedure
Observethefollowingproceduretomeasurethereceivingvoltageresponse.Notethat
theprocedurecallsforanoscilloscopeandatestoscillator.
1Checkthatthebearingandtiltanglevaluesarethesameasforthesourcelevel
measurements.
2ObservetheEchoLevelread-outintheSystemTestmenu.
Thisistheecholevelwhich-withoutasignaloscillatorconnected-isthenoise
levelfortheselectedbearing.ThecurrentvalueisshownontheEcholevelbutton.
3EntertheEchoLevelvalue(noiselevel)intotheVRMeasurementresultstable,
rowA.
4Connectasignaloscillatortothehydrophone.
5Adjusttheoscillatorfrequencyto26.0kHz.
6Connecttheoscilloscopechanneltomeasuretheoutputvoltagetothehydrophone.
7Adjusttheoscillatoroutputvoltageto1Vpp.
8EnterthemeasuredhydrophonevoltageU(p-p)intotheVRMeasurementresults
table,rowB.
9CalculatetheU(rms)UHydrvoltagesintheVRMeasurementresultstable,rowB.
10RetrievetheSensitivityastransmitterSvaluefromtheTesthydrophonedatatable.
→Preparationsandtesthydrophonedataonpage199
EntertheinformationintotheReceivingvoltageresponse(VR)table,rowA.
11RetrievetheUHydrvaluefromtheVRMeasurementsresultstable,andenteritinto
theReceivingvoltageresponse(VR)table,rowB.
12Retrievethe20logRvaluefromtheSLMeasurementsresultstable
→Sourceleveltestresultsonpage202
EnteritintotheReceivingvoltageresponse(VR)table,rowC.
13Adjusttheaudiochannelonthesonartoobtainthestrongestecho.
ReadtheresultingresultfromtheEcholevelbuttonontheSystemTestmenu,and
enteritintotheReceivingvoltageresponse(VR)table,rowD.
14Calculatethevoltageresponsewiththeformulagivenintheheaderrowinthe
Receivingvoltageresponse(VR)table.
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