
SFF8639TestAdapterUserManual(Preliminary)
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©2014WilderTechnologies,LLC
DocumentNo.910‐0034‐000Rev.A(Preliminary)
CalibrationThroughDe‐Embedding
TheSFF‐8639HostandDeviceTestAdaptersarefullypassivecomponents.Therefore,
calibrationcompensatingforthelossesmustoccurwithinthetestinstrumentationthatdrives
theSFF‐8639receiverorlooksattheresponseoftheSFF‐8639transmitter.
The8639‐TPAshaveTouchstoneS4Pfilesforde‐embeddingthe
electricallengthand
losseswithintheTPAuptotheSFF‐8639connectorinterfacepads.(ContactWilder
Technologies,support@wilder‐tech.com
,toobtainacopyoftheS4Pfiles.)TheTouchstoneS4P
filesenablethetestengineertocompensateforthelastfourofthefollowingsixrepeatable,
systematicerrorsthatoccurwhenmovingthereferenceplane:
Signalleakageeffects:Directivityerrors
Signalleakageeffects:Crosstalkerrors
Reflectioneffects:
SourceImpedanceMismatchingerrors
Reflectioneffects:LoadImpedanceMismatchingerrors
Bandwidtheffects:ReceiverTransmissioninTestEquipmenterrors
Bandwidtheffects:ReceiverReflection‐trackinginTestEquipmenterrors
Theseerrorsarecorrectedoneachport.RefertotheInstrumentManualforinstructionson
theinstrument’sspecificde‐embedding
process.
NOTE:Thereferenceplaneistheboundary,bothphysicallyand
electrically,betweenthecalibratedandun‐calibratedportionsof
thecircuit.Everythingoutsidethereferenceplaneisconsidered
partoftheDUT.Anyinstrumentthatdoesnotusecalibrationorde‐
embeddingofthetestfixturedefinestheDUTasthetotalof
externallyconnectedcomponents.Ifthede‐embeddingfile
isnot
used,allofthe8639‐TPAandassociatedcoaxialcables,aswellas
cablesconnectingtheTPAassemblytothetestinstrument,wouldbe
apartoftheDUT.
Non‐repeatableerrors,suchasdriftorrandomerrors,canbereducedbutnotcorrected.
Drifterrorsaggregateovertimeorwithenvironmentalchangessuchastemperatureshift.To
eliminatedrifterrors,performaninstrumentation‐levelcalibration.
Arandomerrorcannotbecorrectedthroughcalibrationsincetheerroroccurredrandomly.
Random
errorsaretypicallyassociatedwitheithertestinstrumentnoiseortestrepeatability
problems.Reducetestinstrumentnoisebyincreasingsourcepower,loweringtheIF
bandwidth,oraveragingresultsovermultiplesweeps.Reducetestrepeatabilityproblems
throughtheuseofatorquewrenchor,again,byaveragingovermultiplesweeps.
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