Matrix 620B - 4.4 Dual-channel Operation; 4.5 ADD Operation; 4.6 Triggering

17
3)AlignthetracewiththehorizontalcenterlineofthegraticulebyadjustingtheCH1POSITIONcontrolandTRACE
ROTATIONcontrol(adjustablebyscrewdriver).
4)ConnecttheprobetotheCH1INPUTterminalandapplythe2Vp-pCALIBRATORsignaltotheprobetip.
5)SettheAC-GNDDCswitchtotheACstate.Awaveformasshowninthefigure44--
WillbedisplayedontheCRTscreen.
6)AjusttheFOCUScontrolsothatthetraceimageappearssharply.d
7)Forsignalviewing,settheVOLTS/DIVswitchandTIME/DIVswitchinappropriate
positionssothatsignalwaveformisdisplayedclearly.
8)AdjustthePOSITIONandPOSITIONcontrolsinappropriatepositionssothatthe
displayedwaveformisalignedwiththegraticuleandvoltage(Vp-p)andperiod(T)canbe
readconveniently.
Theabovearethebasicoperatingproceduresoftheoscilloscope.Itisforsingle-channeloperationwithCH1.Single-channel
operationwithCH2canalsobeachievedinasimilarmanner.Furtheroperationmethodsareexplainedinthesubsequentpages.
4.4Dual-channelOperation
ChangetheVERTMODEswitchtotheDUALstatessothattrace(CH2)isalso
Displayed(TheexplanationintheproceedingsectionisofCH1).Atd1isstateof
procedure,theCHltraceisthesquarewaveofthecalibratorsignalandtheCH2
traceisastraightlinesincenosignalisappliedtothischannelyet.
NowapplythecalibratorsignaltotheverticalinputterminalofCH2withthe,
probeasisthecaseforCH1.SettheAC-GND-DCswitchtotheACstate.Adjust
verticalPOSITIONknobs(11)and(19)sothatbothchannelsignalsaredisplayed
asshowninFigure4-5
Figure4-4
Figure4-5
SignalofCH1
SignalofCH2
18
WhenALT/CHOPswitchisreleased(ALTMODE),theinputsignalsappliedrespectivelytoCHlandCH2appearsonthe
screenalternativelyateachsweep.Thissettingisusedwhenthesweeptimeisshortin2-channelobservation.
WhenALT/CHOPswitchisengaged(CHOPMODE),theinputsignalsappliedtoCH1andCH2areswitchedatabout250kHz
independentofthesweepandatthesametimeappearonthescreen.Thissettingisusedwhenthesweeptimeislongin2-channel
observation.
Wheninthedualchanneloperation(DUALorADDmode),theCHlorCH2signalmustbeselectedforthetriggeringsource
signalbymeansoftheSOURCEswitch.IfbothCHlandCH2signalsareinasynchronizedrelationship,bothwaveformscanbe
displayedstationary;Ifnot,onlythesignalselectedbytheSOURCEswitchcanbestationary.IftheTRIG.ALTpushswitchis
engaged,bothwaveformscanbedisplayedstationary.
AnalgebraicsumoftheCH1andCH2signalscanbedisplayedonthescreenbysettingtheVERTMODEswitchtotheADD
State.ThedisplayedsignalisthedifferencebetweenCHlandCH2signalsiftheCH2INVpushswitchisengaged.
Foraccurateadditionorsubtraction,itisaprerequisitethatthesensitivitiesofthetwochannelsareadjustedaccuratelyat
thesamevaluebymeansoftheVARIABLEknobs.VerticalpositioningcanbemadewiththePOSITIONknobofeither
channel.Inviewofthelinearityoftheverticalamplifiers,itismostadvantagetosetbothknobsintheirmid-positions.
Propertriggeringisessentialforefficientoperationofanoscilloscope.Theusermustbethoroughlyfamiliarwiththe
triggeringfunctionsandprocedures.
(1)FunctionsofMODEswitch:
AUTO:WhentheAUTOswitchisengaged,automaticsweepoperationisselected.inautomaticsweepoperation,thesweep
generatorfreerunstogenerateasweepwithoutatriggersignal.However,itautomaticallyswitchestriggeredsweep
operationifanacceptabletriggersourcesignalispresent.TheAUTOpositionishandywhenfirstsettingupthescope
toobserveawaveform;itprovidessweepforwaveformobservationuntilothercontrolscanproperlyset.Oncethe
controlsareset,operationisoftenswitchenbacktotheNORMtriggeringmode,sinceitAutomatic
sweepmustbeusedforDCmeasurementsansignalsofsuchlowamplitudethattheywillnottriggerthesweep.
4.5ADDOperation
4.6Triggering
ismoresensitive.