Data Sheet

TeledyneLeCroyCorporation GeneralRecordingOptions
248 USBProtocolSuiteUserManual
TheTriggerModeoptiondetermineshowthisbufferisused.AlthoughtheAnalyzerhasa
largephysicalmemory,theefficiencyoftherecordingisabouta2:1ratioofphysical
memorytoactualUSBtraffic.ShorterUSBpacketsyieldaslightlylessefficientrecording.
Thenon‐trafficportionofphysicalmemoryisutilizedforcontrolandtiminginformation.
Note:Thescaleisnotlinearandaffordsmoregranularityinthesmallerbuffersizes.
Note:Tomakethefullbufferavailableforrecording,youcanselecttoDisable Generator Memoryin
theMisc.USB2.0taboftheRecording Optionsdialog(M3iOnly).
5.2.8 Trigger Position
Youcanadjusttheamountofrecordingtobedonepost‐triggerorselectwhereyouwant
theTriggerlocatedwithinthedefinedbuffer.YoucanadjusttheTriggeringPosition
between1and99%post‐trigger.TriggerPositionisavailableonlywhenManual Trigger
orEventTriggerisselectedastriggermode.
Asanexample,ifthebuffersizeissetto16MB,thenforthefollowingTriggerPosition
settings,theamountofpre‐triggerandpost‐triggerdatais:
 95%post‐triggering:0.8MBpre‐trigger,15.2MBpost‐trigger
 75%post‐triggering:4MBpre‐trigger,12MBpost‐trigger
 50%post‐triggering:8MBpre‐trigger,8MBpost‐trigger
 25%post‐triggering:12MBpre‐trigger,4MBpost‐trigger
 5%post‐triggering:15.2MBpre‐trigger,0.8MBpost‐trigger
Note:WhenaTriggeroccurs,recordingcontinuesuntilthepost‐triggeramountofthebufferisfilledor
whenStopisselected.
5.2.9 Options Name
TheOptionsNameisadescriptivelabelofthecurrentRecordingOptionssettings.
OptionsNamesareassociatedwithfilesthathavea.recsuffix.
Thedefaultoptionnameisdefault.DefaultpreservesthecurrentRecordingOptions
settings.
ThepurposeoftheOptionsNameboxistogiveyouaplacetopreservedifferent
RecordingOptionsthatyouuseonarecurrentbasis.Forexample,ifyouusetwoorthree
differentRecordingOptionsconfigurations,youcansavetheseconfigurationsandload
themthenexttimetheyareneeded.
BecauseOptionsNamesaredescriptivelabelsandnotfilenames,youcanenterinany
textyoulikeintothebox.Yourlabelscanbeverydescriptivesuchas"TriggeronHigh
SpeedtrafficwhenCRCerrorsoccur".
TocreateanewRecordingOptionsname:
1. EnteracommentforthenewfileintheOptionsNamefield.
2. ClickSavetodisplaytheSaveAswindow.