PicoQuant MultiHarp 150 - Page 47

PicoQuantGmbH MultiHarpSoftwareV.3.1.0.0
Furtherdownontherightyoufindagroupbox‘FilterTest’.Thisprovidesausefulfeaturefortestingafiltercon-
figuration,andinparticularcheckingastowhethertheresultingdataratemayormaynotbesustainableover
USB.RecallthattheMultiHarphasanextremelyhighinputbandwidth:eachchannelcaninprinciplecapture
eventsatupto1.5GHz.DespiteasophisticatedFIFObufferingscheme(seesection5.3.2)combinedoverthe
instrument’smanychannelsthishighratecannotbesustainedforlongininternalprocessingandUSBtransfer.
ThefiltertestwillpermittotrythisoutwithoutdoingarealmeasurementandrunningintoFIFOoverruns.Be-
causethetestperformsaquasi-realmeasurement,onlywithoutforwardingdatafromthefiltertotheFIFO,it
cannotbeperformedwhenarealmeasurementisrunningandvice-versa.Thecorrespondingbuttonswillbe
mutuallydisabledandgreyedouttopreventthis.
UsingthesetupwiththetwogeneratorsassketchedabovewecannowperformafiltertestbyclickingtheRun
buttonandobservetheInputandOutputrates:

Asexpectedwiththefilterstillbeingdisabled,theOutputRatematchestheInputRate.
Afterstoppingthefiltertestwecanthenproceedtoarealmeasurement.Thisinvolvesthedialogelementsfor
‘AcquisitionSettings’andStatusaswellasthebuttonsSTARTandSTOP.Theprocedureisthesameasinplain
TTTRmodedescribedinsection5.3.4.Weuseanacquisitiontimeof1sandthefilename‘unfiltered.ptu’.After
completionofthemeasurementweleavethefilteredTTTRmodedialogbyclickingEXIT.Whenthesoftwareis
backinhistogrammingmodeweloadthefilewehavejustcollectedintotheregularhistogrammingmodedis-
play.Notethatthisrequiresselectingthefiletype*.ptuinthefileopeningdialog.AsthecollecteddataisfromT3
mode,thesoftwarewillpromptforwhichrangeoftheTTTRrecordsitshouldperformthehistogramming.We
acceptthedefaultsettingofusingtheentirerange.Theresultwillbeasetofhistogramsasshowninthenext
figure:
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