
SATA2.5TestAdapterUserManual
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©2010,2011WilderTechnologies,LLC
DocumentNo.910‐0011‐000Rev.B
1XTHRU
The1X‐THRUisacalibrationfeatureusedtocalibratetimedomaininstrumentation(for
example,pre‐emphasizedpulsegeneratorsorAWGs,arbitrarywaveformgenerators).1X‐THRU
calibrationcompensatestwoerrorsources–cablelossesandgroupdelay:
CableLosses–CablelossesassociatedwiththeSATA2.5plugTPA,and
itsrespectivecabling
that’sconnectedtothetestsource,consistofskinlossand,toalesserextent,dielectricloss.
Pre‐emphasisorde‐emphasisisusedatthesignalsourcetocorrectforthesecablelosses.
Pre‐emphasisisaboostofthesignalleveljustafteranedge
transition;de‐emphasisisa
reductioninthelow‐speedamplitudeofthesignalsource.Typically,onade‐emphasized
signalthelevelshavetoberesettoattainthesameoutputlevels.Resultantsignalsfrom
eitherpre‐emphasisorde‐emphasisareidenticalrelativetotheDUT.
Forthe
purposesofthisdiscussion,pre‐emphasiswillbeused.Tosetthepre‐emphasis,first
determinetheamountofsignalboostbyconnectingthesignalsource,viathe1X‐THRUand
therespectivecableusedtoconnecttheDUTtothesourcetoahigh‐speedoscilloscopeora
jittermeasurement
device.Triggertheoscilloscopeorjittermeasurementdeviceusinga
triggerfromthesource.Thetrigger,asingleevent,indicatesthestartofthesignalbeing
senttotheDUT.Adjustpre‐emphasistomaximizetheeyeopening.
GroupDelay–Groupdelayistheseconderrorsourcefor
1X‐THRUcalibration.Whenthe
DUTgeneratesanoutputsignal,itcanbeusedtomeasuredelay.Tocreateabaselinedelay
measurement,connecttheoutputsignalcabletotheinputsignalcableandthe1X‐THRU.To
determinecorrectedDUTdelay,subtractthisbaselinemeasurementfromtheDUTdelay
measurements.
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