Tektronix 2756P Operating and maintenance manual

-Tpi/PROGRAMMERS
1LUXMANUAL PartNo.:070-6320-00
ProductGroup26
2756P
SPECTRUMANALYZER
Please Check for CHANGE INFORMATION at the Rear of This Manual
FirstPrintingMAR1987
Ibktronix
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Copyright® 1987Tektronix,Inc.Allrightsreserved.
Contentsofthispublicationmaynotbereproducedinany
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byU.S.andforeignpatentsand/orpendingpatents.
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isa registeredtrademarkofTektronixU.K.Limited.
PrintedinU.S.A.Specificationandpricechangeprivileges
arereserved.
Tektronix,Inc.
P.O.Box500
Beaverton,Oregon97077 SerialNumber,

2756PProgrammers
PREFACE
Thismanualisoneofa setofproductmanualsfor
theTEKTRONIX2756PProgrammableSpectrum
Analyzer.Thismanualdescribestheprogrammablefunc-
tionsofthespectrumanalyzerandhowtousethemfor
remoteoperation.Themanualorganizationisshownin
theTableofContents.Themanualsthatareavailable
nowinadditiontothisProgrammersManualarethe
•2756POperatorsManual(standardaccessory)and
•2756PServiceManuals,Volume1 and2 (optional
accessories).
Formanualorderinginformation,contactyourlocal
TektronixFieldOfficeorrepresentativeorrefertothe
AccessoriesportionoftheReplaceableMechanicalParts
listintheServiceManual,Volume2.
StandardsandConventionsUsed
Mostterminologyisconsistentwithstandards
adaptedbyIEEEandIEC.A glossaryoftermsispro-
videdinAppendixA.Abbreviationsinthedocumentation
areconsistentwithANSIY1.1-1972.GPIBfunctionscon-
formtotheIEEE488-1978StandardandtheTektronix
InterfaceStandardforGPIBCodes,Formats,Conven-
tions,andFeatures.CopiesofANSIandIEEEstandards
canbeorderedfromtheInstituteofElectricalandElec-
tronicEngineersInc.ContactyourlocalTektronixField
Officeorrepresentativeifyouhavequestionsregarding
theTektronixreferencedocument.
Change/HistoryInformation
Anychangeinformationthatinvolvesmanualcorrec-
tionsoradditionalinformationislocatedbehindthe
tabbedChangeInformationpageatthebackofthis
manual.
Historyinformation,aswellastheupdateddata,is
combinedwithinthismanualwhenthepage(s)isrevised.
Arevisedpageisidentifiedbya revisiondatelocatedin
thelowerinsidecornerofthepage.
UnpackingandInitialInspection
Instructionsforunpackingandpreparingtheinstru-
mentforusearedescribedinSection3 oftheOperators
Manual.
StorageandRepackaging
Instructionsforshort-andlong-termstorageand
instrumentrepackagingforshipmentaredescribedin
Section3 oftheOperatorsManual.
i

2756PProgrammers
TABLEOFCONTENTS
Page Section2
PREFACE
TABLEOFCONTENTS
LISTOFILLUSTRATIONS.
LISTOFTABLES.
...ii
.vii
.vii
SAFETYSUMMARY. .VIII
Section1 INTRODUCTIONTOGPIBOPERATION
Section2
GPIBPushbuttonandIndicators. .1 1
RESETTOLOCAL/REMOTE 1 -1
PLOT1-2
<SHIFT>SRQ1-2
ADDRESSED1-2
GPIBFunctionReadout1-2
SettingtheGPIBADDRESSSwitches1-2
SettingtheLFOREOISwitch1-3
SettingtheTALKONLYandLISTEN
ONLYSwitches1-4Section3
IEEE488Functions1-4
SourceHandshake(SH1)1-4
AcceptorHandshake(AH1)1-5
Talker(T5)1-5
Listener(L3)1-5
ServiceRequest(SR1)1-5
Remote/Local(RL1)1-5
ParallelPoll(PP1)1-5
DeviceClear(DC1)1-5
DeviceTrigger(DT1)1-5
Controller(CO)1-5
Connectingtoa System1-5
DEVICE-DEPENDENTMESSAGE
STRUCTUREANDEXECUTION
SyntaxDiagrams2-1Section4
SpectrumAnalyzerInputMessages2-1
InputMessageFormat2-1
MessageUnitDelimiter(;)2-2
MessageTerminator(TERM)2-2
FormatCharacters2-2
InputBufferingandExecution2-2
CommandFormat2-2
Header2-3
HeaderDelimiter(SP)2-3
ArgumentDelimiter(,)2-3
ArgumentFormat2-3
Numbers2-3
Units2-4
CharacterArgument2-4
LinkArgument2-4
StringArgument2-4
Page
(continued)
BinaryBlock2-4
EndBlock2-5
QueryFormat2-4
QueryResponseFormat2-4
SpectrumAnalyzerOutputMessages2-5
OutputMessageFormat2-5
OutputMessageExecution2-5
SpectrumAnalyzerCompatibility2-5
GPIB2-5
DEGAUSCommand2-5
IDENTCommand2-5
ReadoutMaximum2-5
ServiceRequests2-5
AffectofBusyonDevice-
DependentMessages2-5
GET(GroupExecuteTrigger)2-6
ReferenceLevel2-6
RDOUTCommand2-6
Compatibility-OnlyCommands2-6
GETTINGSTARTED
SettingandQuerying
ProgrammableControls3-1
SettingProgrammableControls3-1
QueryingProgrammableControls3-2
ExerciseRoutines3-3
Talk/Listen3-3
AcquiringInstrumentSettingswith
theSETQuery3-4
ResettingtheProgrammableSpectrum
AnalyzerandInterfaceMessages3-4
Acquiringa Waveform3-4
GettingSmarter3-5
GettingSmarterAnotherWay3-5
INSTRUMENTCONTROL
UseinMacros4-2
NUMArgumentValues4-2
Frequency4-3
FREQ4-4
TUNE4-4
TMODE4-4
FIRST4
SECOND4
TGMODE4
SAMODE4
DISCOR4
FRQRNG4
STEP4
MSTEP4
PSTEP4
COUNT4

2756PProgrammers
Page
Section 4 (continued)
CRES 4-9
CNTCF 4-9
STSTOP 4-9
DELFR 4-10
DEGAUS 4-10
EXMXR 4-10
IMPED 4-11
FrequencySpan and Resolution 4-12
SPAN 4-13
ZEROSP 4-13
MXSPN 4-14
RESBW 4-14
ARES 4-15
IDENT 4-16
VerticalDisplay and ReferenceLevel....4-17
VRTDSP 4-18
REFLVL 4-18
RLUNIT 4-19
CAL4-20
ENCAL 4-21
FINE 4-22
RLMODE 4-22
RGMODE 4-23
PEAK 4-23
MINATT 4-24
MAXPWR 4-24
RFATT? 4-25
PLSTR 4-25
VIDFLT 4-26
SweepControl 4-27
TRIG 4-27
SIGSWP 4-28
TIME 4-29
DigitalStorage 4-30
AVIEW 4-30
BVIEW 4-31
SAVEA 4-31
BMINA 4-32
DSTORE 4-32
DRECAL 4-32
MXHLD 4-33
CRSOR 4-33
DisplayControl 4-35
REDOUT 4-35
GRAT 4-36
CLIP 4-36
GeneralPurpose 4-37
STORE 4-37
RECALL 4-38
RDATA 4-38
PLOT? 4-39
PTYPE 4-39
POFSET 4-40
ECR4-40
Section 5 MARKERSYSTEM
Usein Macros 5-1
NUM ArgumentValues 5-1
Page
Section 5 (continued)
WaveformFinding 5-1
SystemControl 5-1
MARKER 5-1
MTRACE 5-2
NSELVL 5-3
SGTRAK 5-4
MarkerPositioning 5-4
DPMK 5-4
MAMPL? 5-4
MCEN 5-5
MCPOIN 5-6
MEXCHG 5-6
MFREQ 5-6
MKTIME 5-7
MKDP 5-7
MLOCAT? 5-8
MTOP 5-8
MTUNE 5-8
MarkerFinding 5-9
HRAMPL 5-9
LRAMPL 5-9
BWNUM 5-10
BWMODE 5-10
MFBIG 5-10
MLFTNX 5-11
PKFIND 5-11
PKCEN .5-12
MMAX 5-12
MMIN 5-12
MRGTNX 5-13
THRHLD 5-13
MVLFDB 5-14
MVRTDB 5-14
STYPE 5-16
SGERR 5-19
Miscellaneous 5-19
ZOOM 5-19
Section 6 MACROS
NUM ArgumentValues 6-1
MathCommands 6-1
PLUS 6-1
SUBT 6-1
MULT 6-1
DIVIDE 6-2
RegisterCommands 6-2
PUTREG 6-2
EXCHG 6-3
INTEGR 6-3
POP6-3
ENTER 6-4
Branching and LoopingCommands 6-5
GOTO 6-5
LABEL 6-5
FOR6-6
IF6-7
RETURN 6-8
GOSUB 6-8
iv

2756PProgrammers
Page
Section6 (continued)
PrintCommands6-9
CLEAR6-9
DSLINE?6-9
TEXT6-10
MRDO?6-10
PRINT6-11
DataCommands6-12
MDATA6-12
READ6-12
MRESTO6-12
GeneralPurposeMacros6-13
PAUSE6-13
RUN6-13
DONE6-13
EMAC6-14
KILL6-14
MACRO?6-14
MCSTOP6-14
MEMORY6-15
STNUM6-15
MENU6-15
SWEEP6-15
VAR?6-16
STMAC6-16
GETWFM6-16
INPNUM6-17
Section7 DISPLAYDATAANDCRTREADOUTI/O
NUMArgumentValues7-1
UseinMacros7-1
WaveformTransfers7-1
WFMPRE7-1
CURVE7-4
WAVFRM?7-5
DPRE?7-5
DCOPY?7-6
CrtReadoutTransfers7-6
RDOUT7-7
TEXT7-7
UPRDO?7-8
MDRDO?7-8
LORDO?7-8
Section8 WAVEFORMPROCESSING
NUMArgumentValues8-1
UseinMacros8-1
WaveformFinding8-1
POINT8-1
FIBIG8-2
LFTNXT8-2
RGTNXT8-2
FMAX8-2
FMIN8-3
DataPointCommandsInteraction8-3
CENSIG8-3
TOPSIG8-4
Page
Section9 SYSTEMCOMMANDSANDQUERIES
NUMArgumentValues9-1
UseinMacros9-1
InstrumentParameters9-1
SET?9-1
INIT9-5
ID?9-5
HDR9-6
MessageExecution9-6
WAIT9-6
REPEAT9-6
StatusandErrorReporting9-7
EOS9-7
RQS9-7
SSR9-8
WARMSG9-8
StatusByte9-8
EffectofBusyonDevice-
DependentMessages9-9
EffectofBusyonInterface
Messages9-9
DT9-10
EVENT?9-10
ALLEV?9-10
ERR?9-11
ERCNT?9-11
NUMEV9-11
EVQTY?9-11
TEST?9-11
ErrorCodes9-12
Section10HELPSANDHINTS
ProgrammingTechniques10-1
SignalProcessing10-1
RunningProgramsWithouta
Controller(Macros)10-1
DataAcquisition10-1
SynchronizingControllerand
SpectrumAnalyzer10-2
SynchronizingwiththeSweep10-2
UsingtheEnd-of-SweepSRQ10-4
INPUT:AnSRQAlternative10-4
BinaryWaveformTransfer10-4
GettingSpectrumAnalyzerBinary
CurveOutput10-4
Sendinga BinaryCURVEtothe
SpectrumAnalyzer10-5
Scaling,Saving,andGraphing
WaveformData10-5
SavingtheScaledArray10-5
StoringSettings10-6
UsingPLOT10-6
UsingPLOTWithMacros10-6
MultipleUseofDisplayBuffer10-6
BufferDataFlow10-7
Order-DependentConflicts10-7
FindingSignalswithWaveform
Processing10-7
v

2756PProgrammers
Page
Section9 (continued)
UnderstandingHowWaveform
ProcessingWorks10-7
SettingtheThreshold10-8
AcquiringDataforWaveform
Processing10-9
SpectrumSearch10-9
MeasuringSignalFrequencyWith
COUNT10-9
UsingCOUNT—CF10-9
UsingMCEN10-10
HigherCenterFrequencyDrift
RateAfterTuning10-10
Noise10-10
UsingREPEATforSignalTracking
andSearches10-10
SpectrumSearchUsingREPEAT....10-10
MessagesontheCrtUsing
RDOUT.10-11
UsingCALOvertheBus10-11
ComparingFREQandTUNE10-11
UsingtheTimeMeasurementFeature.10-11
UsingMultibandSweep10-12
ComparingtheStatusByteand
theERR?Response10-13
ExecutionandTransferTimes10-13
Page
AppendixA IEEESTD488(GPIB)SYSTEM
CONCEPTS
MechanicalElementsA-1
ElectricalElementsA-1
FunctionalElementsA-1
ATypicalGPIBSystemA-2
Talkers,Listeners,andControllersA-2
InterfaceControlMessagesA-2
Device-DependentMessagesA-4
GPIBSignalLineDefinitionsA-6
TransferBus(Handshake)A-6
ManagementBusA-6
InterfaceFunctionsandMessagesA-8
RL(Remote-LocalFunction)A-8
T/TEandL/LE(TalkerandListener
Functions)A-8
SHandAH(SourceandAcceptor
HandshakeFunctions)A-9
DC(DeviceClearFunction)A-9
DT(DeviceTriggerFunction)A-9
C,SR,andPP(Controller,Service
Request,andParallelPoll
Functions)A-10
TakingControl(Asynchronousor
Synchronous)A-10
PassingControlA-10
Performinga SerialPollA-10
Performinga ParallelPollA-10
AppendixB PROGRAMMINGFUNCTIONS
ProgrammingSummary
Notes
StatusByte
InterfaceMessages
CommandsandQueries
QuickReferencetoCommandsand
Queries
SampleMacros
MacroPreparation
Pass/FailHarmonicTest
Macros(Continued)
HarmonicMacroTest
OutputFortheHarmonicMacro
Test
Front-PanelRelationshiptoMnemonics
ERR7/ERCNT?Responses
ERR?Responses(NumericalOrder)
vi

2756PProgrammers
LISTOFILLUSTRATIONS
Figure
Number Page Figure
Number Page
1-1
1-2
1-3
1-4
1-5
1-6
4-1
4-2
4-3
4-4
4-5
4-6
4-7
TEKTRONIX2756PProgrammable
SpectrumAnalyzerx
GPIBpushbuttonandindicators1-1
StatusofactiveGPIBfunctions1-2
Rear-panelGPIBADDRESSswitches1-3
Effectofmessageterminatorswitchfor
inputandoutput1-4
Therear-panelIEEESTD488PORT(GPIB)1-5
Thespectrumanalyzercanbeconnectedtoa
GPIBsystemineithera starora linear
pattern1-6
Front-panelFrequencycommands4-3
Front-panelFrequencySpanandResolution
commands4-12
Front-panelVerticalDisplayandReference
Levelcommands4-17
Front-panelSweepControlcommands4-27
Front-panelDigitalStoragecommands4-30
Front-panelDisplayControlcommands4-35
Front-panelGeneralPurposecommands4-37
5-1UsingthePKFINDcommand5-12
5-2Locatingthesignalpeak5-15
5-3Signalfindingexample5-16
5-4Signalfindingexample5-17
5-5Signalfindingexample5-17
5-6Signalfindingexample5-18
5-7Signalfindingexample5-19
6-1INPNUMexample6-18
7-1Waveformdatarelatedtothedisplay7-5
9-1Testconversionchart9-13
10-1Synchronizingcontrollerandspectrum
analyzerfordataacquisition10-3
10-2Howmultipleuseofthedisplaydatabuffer
iscontrolled10-8
A-1IEEEStd488(GPIB)connectorA-1
A-2A typicalGPIBsystemA-3
A-3ASCII& GPIBCodeChartA-5
A-4Anexampleofdatabytetrafficonthe
GPIBA-7
A-5A typicalhandshaketimingsequenceA-7
LISTOFTABLES
Table
NumberPage
1-1BusAddresses1-3
1-2SpectrumAnalyzerIEEE488Interface
Functions1-4
4-1Front-panelCommandsandQueries4-1
4-2ResolutionBandwidthSelection4-15
4-3ReferenceLevelSteps4-19
4-4CalibrationCodes4-21
5-1MarkerTraceOrganization5-2
Table
NumberPage
6-1ErrorMessages6-14
9-1InstrumentFunctions9-5
9-2WarningMessages9-8
9-3TestConversion9-12
9-4ErrorandEventCodes9-14
10-1ExecutionandTransferTimes10-14
A-1MajorGPIBInterfaceFunctionsA-2
A-2InterfaceMessagesandFunctionsA-4

2756PProgrammers
SAFETYSUMMARY
(Referallservicingtoqualifiedservicingpersonnel)
Thesafetyinformationinthissummaryisforboth
operatingandservicingpersonnel.Specificwarningsand
cautionswillbefoundthroughoutthemanualwherethey
apply,butmaynotappearinthissummary.
CONFORMANCETOINDUSTRY
STANDARDS
AsMarkedonEquipment
CAUTIONindicatesa personalinjuryhazardnot
immediatelyaccessibleasonereadsthemarking,ora
hazardtoproperty,includingtheequipmentitself.
DANGERindicatesa personalinjuryhazardimmedi-
atelyaccessibleasonereadsthemarking.
ThisinstrumentcomplieswiththefollowingIndustry
SafetyStandardsandRegulatoryRequirements.
SYMBOLS
Safety
CSA:ElectricalBulletin
FM:ElectricalUtilizationStandardClass3820
ANSIC39.5— SafetyRequirementsforElectrical
andElectronicMeasuringandControlling
Instrumentation.
IEC348(2ndedition)— SafetyRequirementsfor
ElectronicMeasuringApparatus.
InThisManual
A Thissymbolindicateswhereapplicablecau-
tionaryorotherinformationistobefound.
AsMarkedonEquipment
DANGER— Highvoltage.
RegulatoryRequirements
VDE0871ClassB — RegulationsforRFISup-
pressionofHighFrequencyApparatusandInstal-
lations.
A
©
Protectiveground(earth)terminal.
ATTENTION— refertomanual.
Refertomanual
TERMS POWER
InThisManual
CAUTIONstatementsidentifyconditionsorpractices
thatcouldresultindamagetotheequipmentorother
property.
WARNINGstatementsidentifyconditionsorpractices
thatcouldresultinpersonalinjuryorlossoflife.
PowerSource
Thisproductisintendedtooperatefroma power
sourcethatwillnotapplymorethan250V rmsbetween
thesupplyconductorsorbetweeneithersupplyconduc-
torandground.A protectivegroundconnectionbyway
ofthegroundingconductorinthepowercordisessential
forsafeoperation.
viii

2756PProgrammers
IGroundingtheProduct OPERATIONALPRECAUTIONS
Thisproductisgroundedthroughthegroundingcon-
ductorofthepowercord.Toavoidelectricalshock,plug
thepowercordintoa properlywiredreceptablebefore
connectingittothepowerterminal.A protectiveground
connectionbywayofthegroundingconductorinthe
powercordisessentialforsafeoperation.
DangerFromLossofGround
Uponlossoftheprotective-groundconnection,all
accessibleconductiveparts(includingknobsandcon-
trolsthatmayappeartobeinsulating)canrenderan
electricshock.
UsetheProperPowerCord
Useonlythepowercordandconnectorspecifiedfor
yourproduct.
Useonlya powercordthatisingoodcondition.
CSAcertificationappliestothespectrumanalyzer
withCSA-certifiedpowercordsonly(thepowercord
shippedwithyourinstrumentandTektronixOptionA4).
Internationalpowercords(TektronixOptionsA1,A2,A3,
landA5)areapprovedonlyforthecountryofuse,and
arenotincludedintheCSAcertification.
Refercordandconnectorchangestoqualifiedser-
vicepersonnel.
Fordetailedinformationonpowercordsandconnec-
tors,seetheMaintenancesectionintheServiceManual,
Volume1.
DoNotOperateinExplosiveAtmospheres
Toavoidexplosion,donotoperatethisproductinan
explosiveatmosphereunlessithasbeenspecifically
certifiedforsuchoperation.
DoNotRemoveCoversorPanels
Toavoidpersonalinjury,donotremovetheproduct
coversorpanelsunlessyouarequalifiedtodoso.Do
notoperatetheproductwithoutthecoversandpanels
properlyinstalled.
Dangerousvoltagesexistatseveralpointsinthis
product.Toavoidpersonalinjury,donottouchexposed
connectionsandcomponentswhilepowerison.REFER
ALLSERVICINGTOQUALIFIEDSERVICEPERSONNEL.
UsetheProperFuse
Toavoidfirehazardorequipmentdamage,useonly
thefuseofcorrecttype,voltagerating,andcurrentrating
foryourproduct(asspecifiedintheReplaceableElectri-
calPartslistinVolume2 oftheServiceManual).Refer
fusereplacementtoqualifiedservicepersonnel.
ix

2756PProgrammers
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Section1 — 2756PProgrammers
INTRODUCTIONTOGPIBOPERATION
TheTEKTRONIX2756PProgrammableSpectrum
AnalyzercanbecontrolledremotelyviatheGeneralPur-
poseInterfaceBus.Waveformprocessingfunctionsare
addedtodosomespectrumanalysislocally.
TheIEEESTD488GeneralPurposeInterfaceBus
(GPIB)portinthespectrumanalyzerrearpanelallowsit
tobeusedwitha widevarietyofsystemsandcontroll-
ers;theinstrumentfollowstheTektronixInterfaceStan-
dardforGPIBCodes,Formats,Conventions,and
Features.Thisstandardpromoteseaseofoperationand
makesthisspectrumanalyzercompatiblewithotherTek-
tronixinstrumentsand,asmuchaspossible,withGPIB
instrumentsfromothermanufacturers.
GPIBPUSHBUTTONANDINDICATORS
(seeFigure1-1)
RESETTOLOCAL/REMOTE
TheREMOTEindicatorislitwhenthespectrum
analyzerisundercontroloftheGPIBcontroller.While
underremotecontrol,theotherfront-panelcontrolsand
pushbuttonsarenotactive;indicatorswillstillreflectthe
currentstateofallfront-panelfunctionsexcept
TIME/DIV,MINRFATTENdB,andPEAK/AVERAGE.
REMOTE
(INDICATOR)
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ADDRESSEDRESETTOLOCAL
(INDICATOR)
6320-01
Figure1-1.GPIBpushbuttonaridIndicators.
1-1

Introduction toGPIBOperation— 2756PProgrammers
TheREMOTEindicatorisnotlitwhentheinstrument
isunderlocal,operatorcontrol.Whileunderlocalcon-
trol,theinstrumentdoesnotexecuteGPIBmessages
thatwouldconflictwithfront-panelcontrols,anditdoes
notaccepttheCURVEinputcommand.
Whentheinstrumentisunderremotecontroland
RESETTOLOCALispressed,localcontrolisrestoredto
theoperatorunlessthecontrollerpreventsthiswiththe
locallockoutmessage.Programmablefunctionsdonot
changewhenswitchingfromremotetolocalcontrol
exceptasnecessarytomatchthesettingsoffront-panel
controlsforTIME/DIV,MINRFATTENdB,and
PEAK/AVERAGE.
Thespectrumanalyzerflashestheinstrumentname,
firmwareversionnumber,theGPIB'address,andthe
macrostatusmessageonthecrtwhenRESETTO
LOCALispressed.Ifthereisnomacrorunning,themes-
sagewillbeMACRO—OFF(#)where# indicatesthe
menulocationofthelastmacrothatwasrun.Ifthereisa
macrorunning,themessagewillbeMACRO-RUN(#)
where# indicatesthemenulocationofthemacrothatis
running.Ifthereisa macroinprocessbutstopped,the
messagewillbeMACRO-STOP(#)where# indicates
themenulocationofthemacrothatisstopped.Ifa
macroisbeingstoredinmemory,themessagewillbe
MACRO—STORE(#)where# indicatesthemenulocation
wherethemacroisbeingstored.
PLOT
Pressthispushbuttonwhenthespectrumanalyzeris
inthetalk-onlymodefortheinstrumenttosendthe
appropriatecommandsovertheGPIBtoa plotter,which
mustbeinthelisten-onlymode,connectedtothebus
(seetheTALKONLY,LISTENONLYswitchdescriptions
laterinthissection).Thespectrumanalyzerdisplay
(waveform,marker(s),graticule,andcrtreadout)canbe
recreatedona TEKTRONIX4662Option01or4662
Option31InteractiveDigitalPlotter(ora 4663inthe
4662emulationmode);ora Hewlett-PackardHP7470Aor
HP7475A,HP7580B,HP7585B,orHP7586B;ora Gould
6310or6320plotter.Selectplottertypewith<SHIFT>
SELECTTYPE,describedinSection4 ofthismanual.A
buscontrollerisnotrequired.
<SHIFT>SRQ
ThisSRQ(servicerequest)pushbuttonsequence
getsthecontroller'sattentionsoitwilllisten/respondto
thespectrumanalyzer.Forexample,ifthecontrollerput
instructionsonthescreen,intheTEXTLONGmode,to
setuptestequipment,etc.,thelastlineoftheinstruc-
tionsmightsayTRESS<SHIFT>SRQWHENREADY".
Thiswouldinstructthecontrollertogoontothenext
step.AnSRQwillonlybeissuedifRQSison.
ADDRESSED
Thisindicatorislitwhenthespectrumanalyzeris
addressedtolistenortalk.
GPIBFunctionReadout
Asinglecharacterappearsinthelowercrtreadout
whenthespectrumanalyzeristalking(T),orlistening(L);
seeFigure1-2.Twocharacterswillappearinthisloca-
tioniftheinstrumentistalkingorlisteningandalso
requestingservice(S),oriftheinstrumentisinboththe
talk-onlyandlisten-onlymodes.
Figure1-2.StatusofactiveOPIBfunctions.
SettingtheGPIBADDRESSSwitches
Therear-panelGPIBADDRESSswitchesshownin
Figure1-3setthevalueoftheGPIBaddress(referto
Table1-1).Theinstrument'sprimaryaddress(0through
31)isthevalueofthelowerfivebits,whicharelabeled4
through8 inFigure1-3.Theseswitchesarereadeach
timepoweristurnedontotheinstrumentandagaineach
timetheRESETTOLOCALorPLOTpushbuttonis
pressed.
1-2

IntroductiontoGPIBOperation— 2756PProgrammers
Table1-1
BUSADDRESSES
GPIBADDRESS
LFOREOl•
TALKONLY•
LISTENONLY -
16(
I 1
I
45 6 7 8
OPEN
EOl
•415-03
Figure1-3.Rear-panelGPIBADDRESSswitches.TheLFOR
EOlswitch(messageterminator)andtheTALKONLYand
LISTENONLYswitchesarepartofthesameswitchbank.
Theaddresstransmittedbythecontrollerisseven
bitswide.Thefirstfivebitsaretheprimaryaddressand
thelasttwobitsdeterminewhetheritisa listenaddress
(32+ primaryaddress)ortalkaddress(64+ primary
address).Forexample;0100010isprimaryaddress2 a
listener,and1000010isprimaryaddress2 a talker.
Secondaryaddresses(whenbothbits6 and7 areset)
arenotusedbythespectrumanalyzer,soareignored.
Settheswitchesasdesired,butdonotuseaddress
0withTektronix4050-Seriescontrollers;theyreserve
thisaddressforthemselves.Selectinga primaryaddress
of31logicallyremovesthespectrumanalyzerfromthe
bus;itdoesnotrespondtoanyGPIBaddress,but
remainsbothunlistenedanduntalked.Remember,ifyou
changetheseswitcheswhentheinstrumentisrunning,
youmustpressRESETTOLOCALorPLOTtocausethe
primaryaddresstobeupdated.
SettingtheLFOREOlSwitch
Switch3 oftherear-panelGPIBADDRESSswitch
bank(seeFigure1-3)selectstheterminatorformes-
sagesonthebus.IfLFOREOlisselected(switchup,
1),thespectrumanalyzerinterpretseitherthedatabyte
LFortheendmessage(EOlassertedconcurrentlywitha
databyte)astheendofa message.IfEOlisselected
(switchdown,0),thespectrumanalyzerinterpretsthe
endmessage(EOlassertedaswellasa databyte)as
theendofa message.
Primary Listen Talk
Address Address Address
168 4 2 1
00000 0 32 64
00001 1 33 65
00 0 1 0 2 34 66
00011 3 35 67
00100 4 36 68
00101 5 37 69
00 110 6 38 70
00111 7 39 71
01000 8 40 72
01001 9 41 73
01010 10 42 74
01011 11 43 75
01100 12 44 76
01101 13 45 77
01110 14 46 78
01111 15 47 79
10 0 0 0 16 48 80
10001 17 49 81
10010 18 50 82
10011 19 51 83
10100 20 52 84
10101 21 53 85
10110 22 54 86
10111 23 55 87
11000 24 56 88
11001 25 57 89
11010 26 58 90
11011 27 59 91
11100 28 60 92
11101 29 61 93
11110 30 62 94
11111 31 UNL UNT
Switch3 alsoselectstheoutputterminator.SettoLF
OREOl,theinstrumentaddsCRandLF(withEOl
assertedaswellasLF)afterthelastbyteofthemes-
sage.SettoEOl,theinstrumentassertsEOlcon-
currentlywiththelastbyteofthemessage.
Figure1-4showstheeffectofthisswitchforboth
inputandoutput.
SelectEOl(switchdown)forTektronixcontrollers.
Theotherpositionofthisswitchisprovidedtoaccom-
modatemostothercontrollers.A changeinthisswitch
takesimmediateeffect.
1-3

Introduction toGPIBOperation— 2756PProgrammers
LFOREOI
OPEN
EOI
INPUT EOII
DATA
BYTE
OUTPUT
EOI&
LAST
DATA
BYTE
ASWITCHDOWNSetforusewithTektronucontrollers.
LFOflEOI
OPEN
EOI
BSWITCHUP 5559-13
SettingtheTALKONLYandLISTENONLY
Switches
Thespectrumanalyzerswitchesfortalk-onlyand
listen-onlyoperationarepartoftheGPIBADDRESS
switchbankshowninFigure1-3.Either,orboth,switch
isonwhenitisintheup,or1,position,andeitherisoff
inthedown,or0,position.Ifinstrumentpowerison,
pressRESETTOLOCALorPLOTfora changeinthese
switchestotakeeffect.
BoththeTALKONLYandLISTENONLYswitches
mustbeoffwhenthespectrumanalyzerisusedwithany
controller.Ascontrast,bothswitchesmustbeonto
allowspectrumanalyzeroutputtobeexchangedwitha
storagedevicewithouttheneedofa controller.The
TALKONLYswitchmustbeontoallowspectrum
analyzeroutputtobesenttoa plotter.WiththeLISTEN
ONLYswitchon,informationsenttoa storagedevice
canbefedbacktothespectrumanalyzer.
IEEE488FUNCTIONS
ThespectrumanalyzeriscompatiblewithIEEESTD
488-1978.Theconnectorandthesignallevelsatthecon-
nectorfollowthespecificationsintheIEEE488standard
(refertoAppendixA inthismanualforthebasiccon-
ceptsoftheIEEE488standard).Table1-2listsinterface
capabilitiesasdefinedinthestandard.
Table1-2
PROGRAMABLESPECTRUMANALYZER
IEEE488INTERFACEFUNCTIONS
Function ImplementedAs
SourceHandshake SH1
AcceptorHandshake AH1
Talker T5
Listener L3
ServiceRequest SR1
RemoteLocal RL1
ParallelPoll PP1
DeviceClear DC1
DeviceTrigger DT1
Controller CO
Figure1-4.EffectofmessageterminatorswitchforInputand
output SourceHandshake(SH1)
Thespectrumanalyzerhascompletecapabilityto
transfermessagestootherdevicesonthebus.Although
tri-statedriversareusedonthedatalines,T1(DAV
delayfordatasetting)isgreaterthan2 us.
1-4

IntroductiontoGPIBOperation— 2756PProgrammers
AcceptorHandshake(AH1)
Thespectrumanalyzerhascompletecapabilityto
receivemessagesonthebus.
Talker(T5)
Thespectrumanalyzerhasthecompletetalkerfunc-
tionincludingserialpoll;unaddressesasa talkerwhen
addressedasa listener.Theinstrumentoperatesina
simplesystemina talk-onlymodeiftheTALKONLY
switchissetto1,up.
Listener(L3)
Thespectrumanalyzerhasthecompletelistener
function;unaddressesasa listenerwhenaddressedasa
talker.Theinstrumentoperatesina simplesystemina
listen-onlymodeiftheLISTENONLYswitchissetto1,
up.
ServiceRequest(SR1)
Thespectrumanalyzerhasthecompleteservice
requestfunction;assertsSRQ(servicerequest)forthe
conditionsindicatedunderSTATUSBYTEinSection9 in
thismanualandreportsthecorrespondingstatuswhen
polled.
Remote/Local(RL1)
Thespectrumanalyzerhasthecompleteremote/local
function.Thefront-panelRESETTOLOCALpushbutton
returnstheinstrumentfromremotetolocalcontrol
unlesstheLLO(locallockout)messagewaspreviously
received.TheGTL(gotolocal)messagealsoreturns
theinstrumentfromremotetolocalcontrol.Refertothe
discussionunderSTATUSBYTEinSection9 ofthis
manualfortheeffectofbusystatusonremote/localtran-
sitions.
Thecurrentvalueofmostprogrammablefunctionsis
maintainedwhenswitchingfromlocaltoremotecontrol.
OnlythevalueofTIME/DIV,MINRFATTENdB,and
PEAK/AVERAGEmaychangetomatchthefront-panel
controlsettingswhenswitchingfromremotetolocal
control,sotheywon'tconflictwithlocalcontrol.
Thespectrumanalyzermustbeunderremotecontrol
tobeginexecutingdevice-dependentmessagesthat
changethestateoflocalcontrolsortoloaddatainto
digitalstorage.Oncebegun,executioncontinuesevenif
REN(remoteenable)goesfalse.Thespectrumanalyzer
changessettingsforwhichthereisnolocalcontroland
outputsdatawhileunderlocalcontrol.
ParallelPoll(PP1)
Thespectrumanalyzerrespondstoa parallelpollto
indicateifserviceisrequested.
DeviceClear(DC1)
ThespectrumanalyzerrespondstotheDCL(device
clear)andSDC(selecteddeviceclear)interfacemes-
sagesbyresettingitsinputandoutputbufferstorestart
buscommunications.Whenthesemessagesareexe-
cuted,theyclearoutstandingSRQconditionsandsetthe
ERRqueryresponsetozero.Power-upstatus,if
selectedinternally,isanexception;seeSTATUSBYTEin
Section9 ofthismanualformoreonpower-upstatus
andfortheaffectofbusystatusontheexecutionofDCL
andSDC.
DeviceTrigger(DT1)
ThespectrumanalyzerDT(devicetrigger)function
allowstheGET(groupexecutetrigger)messageto
causetheinstrumenttostopthecurrentsweepand
rearmforthenewsweep.Thenewsweepbeginswhen
thetriggeringconditionsaremet.TheDTcommandmust
beonandtheinstrumentmustbeintheRemotemode
forGETtohaveanyeffect.
Controller(CO)
Thespectrumanalyzerdoesnotactasa controller.
CONNECTINGTOA SYSTEM
Thespectrumanalyzercanbeconnecteddirectlytoa
GPIBsystemwiththecableavailableasanoptional
accessory(contactyourlocalTektronixFieldOfficeor
representativefororderinginformation).TheIEEESTD
488PORTisshowninFigure1-5.PrintedundertheIEEE
STD488PORTaretheInterfaceFunctionabbreviations
andthecodesindicatingtheiruseintheinstrument(refer
toIEEE488Functionsearlierinthissectionforanexpla-
nationofeachfunction).TheE2followingthefunctions
indicatesthatthree-statedriversareused,ratherthan
open-collectordrivers,becauseofthehigh-speedopera-
tionoftheinstrument.
1-5

IntroductiontoGPIBOperation— 2756PProgrammers
JL IISV MAX
-OUTPUT—
rERCORDPROTECTIVE(MOUNDING
EARTHGROUNDDONOTREMOVE
LIFIEDPERSONNEL )"-FC
OPTIONTAL'
OPTIONL|ST
IEEESTD488PORT
© ©
SH1,AH1,T5,L3,SR1,RL1,PP1,DC1,DT1,CO,E2
4415-06
Figure1-5.Therear-panelIEEESTD488PORT(GPIB).
TheGPIBisa flexiblesystemthatworkseitherina
starorlinearpatternshowninFigure1-6.Upto15dev-
icescanbeconnectedatonetime.Tomaintainbus
electricalcharacteristics,nomorethanone2-meter
cableshouldbeconnectedforeachdevice(oneforthe
controller,oneforthespectrumanalyzer,andsoon),
andatleasttwo-thirdsofthedevicesconnectedmustbe
on.(AppendixA detailstheIEEESTD488GPIBSystem
Concepts.)
Aninternalswitchchangecausesthespectrum
analyzertoassertSRQwhenpowerisfirstapplied.This
requiresimmediateactionbysomecontrollers,soisnot
recommendedforthesecontrollers.Becausechanging
theswitchrequiresthatthecoverberemoved,referthis
tasktoqualifiedservicepersonnel.
Theinstrumentstart-upprocedureisprovidedinboth
theOperatorsManualandtheOperatorsHandbook.
Refertothosebooksforinstructionsonhowtobegin
operatingtheinstrument.RefertoyourlocalTektronix
FieldOfficeorrepresentativeforManualorderinginfor-
mation.
Theinitialpower-onsettingofallprogrammablefunc-
tionsisrestoredbytheINITcommand.RefertoSection
9ofthismanualformoreonthiscommandanda listof
theinitialpower-onsettings.
Figure1-6.Thespectrumanalyzercanbeconnectedtoa
GPIBsystemIneithera star(A)ora linear(B)pattern.
1-6

Section2 — 2756PProgrammers
DEVICE-DEPENDENTMESSAGE
STRUCTUREANDEXECUTION
Thegoaloftheprogrammablespectrumanalyzer
device-dependentmessagestructureistoenhancecom-
patibilitywitha varietyofGPIBsystems,yetbesimple
andobvioustouse.
Thisgoalisachievedwithintheframeworkofthe
TektronixInterfaceStandardforGPIBCodes,Formats,
Conventions,andFeatures.Thisstandardisintendedto
makemessagesonthebusclearanduncomplicated,
whileallowingtheinstrumenttohandlemessagesina
friendlymanner(i.e.,toacceptvariationsinthemes-
sage).Compatibilitywithexistingdevicesismaintained
asmuchaspossible,whileuseofcodesanddatafor-
matsisencouragedtomakemaximumuseofbuscapa-
bilities.
Tomakespectrumanalyzermessageseasytounder-
standandwrite,ordinaryengineeringtermsareused.
Messagecodes(mnemonics)arechosentobeshort,yet
remindyouoftheirfunction.Forexample,tosetthe
instrumentcenterfrequencyto500.000MHz,themes-
sageFREQ500.000MHZcouldbesentoverthebus
aftertheinstrumenthasbeenaddressedasa listener.
Variationsonthismessageareallowedtomakeit
shorterorsendthefrequencyinscientificnotation,but
thisexampleshowstheconversationalformatofspec-
trumanalyzermessagesthatmakesthemreadable;
therefore,human-oriented.
Thespectrumanalyzerdevice-dependentmessages
inthismanualaredownwardcompatiblewiththeTek-
tronix490P-Series,490AP/2750P-Seriesprogrammable
spectrumanalyzers,exceptasnotedlaterinthissection
underSpectrumAnalyzerCompatibility.
Boxesareusedfordefinedelementsandcontaina
namethatstandsfortheelementdefinedelsewhere.
NUMissuchannameandisdefinedunderNumbers
laterinthissection.
Elementsofthesyntaxdiagramareconnectedby
arrowsthatshowthepossiblepathsthroughthediagram
(i.e.,thesequenceinwhichelementsmustbe
transferred).Parallelpathsmeanthatone,andonlyone,
ofthepathsmustbefollowed;whilea patharoundan
elementorgroupofelementsindicatesanoptionalskip.
Arrowsindicatethedirectionthatmustbefollowed(usu-
allytheflowistotheright;but,ifanelementmaybe
repeated,anarrowreturnsfromtherighttotheleftof
theelement).Someexamplesofsuchsequencesfollow.
SYNTAXDIAGRAMS
Spectrumanalyzermessagesarepresentedinthis
manualinsyntaxdiagramsthatshowthesequenceof
elementstransferredoverthebus.Eachelementis
enclosedina circle,oval,orbox.
Circlesorovalscontainthemnemonicsforliteralele-
ments;i.e.,a characterorstringofcharactersthatmust
besentexactlyasshown.Becausemostmnemonics
maybeshortened,therequiredcharactersincommand
andqueryliteralelements(i.e.,thefirstthreecharacters
oftheelement)areshownlargerthanoptionalcharac-
ters.Althoughmnemonicsareshownalluppercase,the
spectrumanalyzeracceptseitherupper-caseorlower-
caseASCIIcharacters.Queryresponsecharactersare
shownexactlyastheywillbereturned.
SPECTRUMANALYZERINPUTMESSAGES
InputMessageFormat
Aremotecontrolmessagetothespectrumanalyzer
comprisesoneormoremessageunitsoftwotypes.The
messageunitseitherconsistofcommandsthatthespec-
trumanalyzerinputsascontrolormeasurementdata,or
theyconsistofqueriesthatrequestthespectrum
analyzertooutputdata.
2-1

DeviceDependentMessageStructureandExecution— 2756PProgrammers
Oneormoremessageunitscanbetransmittedasa
messagetothespectrumanalyzer.Messageunitscon-
tainASCIIcharacters(binarymayalsobeusedfor
waveforms).Thespectrumanalyzeracceptseither
upper-caseorlower-casecharactersforthemnemonics
showninthesyntaxdiagrams.
MessageUnitDelimiter(;)
Messageunitsareseparatedbya semicolon(;).A
semicolonisoptionalfollowingthelastmessageunit.
InputBufferingandExecution
Thespectrumanalyzerbufferseachmessageit
receiveswitha capacitythatexceedsthatrequiredfor
theSET?response.Thespectrumanalyzerwaitsuntil
theendofthemessagetodecodeandexecuteit.A
commanderrorinanypartofa messagepreventsits
execution.Whentheinstrumentisunderlocalcontrol,
commandsthatwouldconflictwithlocalcontrolare
ignored(seeRemote/LocalunderIEEE488Functionsin
Section1 ofthismanual).
Ifthemessagecontainsmultiplemessageunits,none
areactedonuntiltheinstrumentseestheend-of-
messageterminator.Whenthespectrumanalyzersees
theterminator,itexecutesthecommandsinthemes-
sageintheordertheywerereceived.Theinstrument
remainsbusyuntilitisdoneexecutingthecommandsin
thebuffer,unlesstheprocessisstoppedbytheDCL
(DeviceClear)orSDC(SelectedDeviceClear)interface
messages.Whilebusy,furtherinputisnotaccepted(see
STATUSBYTEinSection9 inthismanualformoreon
busystatus).Output,ifrequested,isbegunonlyafterthe
entireinputmessageisexecuted.
Becausedisplay(measurement)datainputandout-
putandwaveformprocessingsharethesamebuffer,
conflictscanarise.ThisisdiscussedintheInteraction
partoftheCURVEcommandinSection7,underDisplay
DataPointCommandsInteractioninSection8,andis
furtherexpandedonunderMultipleUseofDisplayBuffer
ForWaveformProcessingandI/OinSection10,allin
thismanual.
MessageTerminator(TERM)
Theend-of-messageterminatormaybeeitherthe
ENDmessage(EOlassertedconcurrentlywiththelast
databyte),ortheASCIIcodeforlinefeed(LF)sentas
thelastdatabyte.
Theactiveterminatorisselectedbytherear-panel
GPIBADDRESSswitch3.
CommandFormat
Acommandmessageuniteithersetsanoperating
modeorparameter,orittransfersdisplaydatatothe
instrument.Thecommandformattoseta modeor
parameterincludesthefollowingpossiblepaths.
FormatCharacters
Formatcharactersmaybeinsertedatmanypointsto
makethemessagemoreintelligible,butarerequiredonly
iftheyareincludedasa literalelement(i.e.,incirclesor
ovals)withnobypass.Allowableformatcharactersare
SP(space),CR(carriagereturn),andLF(linefeed—
unlesstheendofmessageterminatorissetforLF),as
wellasallotherASCIIcontrolcharactersandcomma(,).
Atsomepointsina message,thespectrumanalyzermay
acceptothernon-alphanumericcharacters,suchasquo-
tationmarks(").
2-2

DeviceDependentMessageStructureandExecution— 2756PProgrammers
Becausethegeneralcommandformatfordisplay
datatransfersiscomplicated,itisomitted;seethedata
I/OcommandsinSection7 ofthismanualforthespecific
commandsyntax.
Header
Headerelementsaremnemonicsthatrepresenta
function;forexample,FREQforcenterfrequencyand
CURVEforthedisplaytrace.
HeaderDelimiter(SP)
Aspace(SP)mustseparatetheheaderfromany
argument(s).
ArgumentDelimiter(,)
Acomma(,)mustseparateindividualarguments,and
acolon(:)mustseparatelinkarguments.
ArgumentFormat
Thefollowingdiagramillustratesthatargumentsfol-
lowingtheheadermaybea number,a groupofcharac-
ters,oreithera numberora groupofcharacterslinked
toanotherargument.
IATFORMAT
CHARACTER
UNITS
CHARACTER
ARGUMENT
CHARACTER
ARGUMENT
Numbers
ThedefinedelementNUMisa decimalnumberinany
ofthreeformats;NR1,NR2,orNR3.
NR1isaninteger(nodecimalpoint).
NR2isa floatingpointnumber(decimalpoint
required).
NR3isa floatingpointnumberinscientificnotation.
NUMargumentsmayservetwofunctions.Thefirstis
toselectthevalueofa continuousfunction(forexample,
thecenterfrequencywithFREQ).Inthiscase,ifNUM
exceedstherangeofthefunction,thespectrumanalyzer
doesnotexecutethecommand,butissuesanerrormes-
sage(seePOINTinSection4 inthismanualforan
exception).Numberswithintherangearerounded.
Thesecondfunctionofa NUMargumentistosubsti-
tuteforcharacterargumentsinON/OFFormodeselec-
tion.Inthiscase,ifNUMexceedstheselectionrange,it
isroundedtothenearestendoftherange.Noerror
messageisissued.Numberswithintherangeare
rounded.
2-3