PicoQuant MultiHarp 150 - Page 52

PicoQuantGmbH MultiHarpSoftwareV.3.1.0.0
Thepartoftheredhistogramthatwaspreviouslykeptinisnowpunchedoutandthebluepeakisdiminished
muchless,accordingtotheratioofremovedversusunremovedeventsintheredhistogram.
Thisconcludesourdemonstrationofthefilteroperationbutsomemorepracticalhintsshallbegivenhere:
Itispossibleandquiteusefultokeepthefiltertestrunningwhileplayingwiththeindividualfiltersettingsandob-
servingtheoutputrate.However,anychangeoffiltersettingsmustalwaysbeconfirmedwithApplyinorderto
takeeffect.
Insomeapplicationscenariositmaybeworthconsideringanothertypeoffilter.Infactathardwarelevelthere
aretwotypesoffilters:TheRowFiltersandtheMainFilter.ThegraphicalMultiHarpsoftwareimplementsonly
thelatter.Thisismainlyforsimplicity,becauseonlytheMainFiltercanactonallchannelsaswellasthesync
channelsimultaneously.Inordertoachievethis,itneededtobeimplementedinthemainFPGAthatcollects
andmergesallthedatafromtheindividualmeasurementmodulesbeforetransmittingitoverUSB.Thedraw-
backofthisis,thatanoverloadofdataratewithintheindividualmeasurementmodules(onerowofinputs)can-
notbepreventedthisway.Althoughitisunlikelythatmanyapplicationswillrunintothislimit(about200Mcps
perrow)wealsoimplementedtheRowFilters.Thesecanalsobeusefulifyourequiremorecomplicatedfilter
conditions,e.g.,withmultipledifferenttimeranges.Inthatcasethetwofilterscanbedaisy-chained.However,in
ordertodothisyouwillhavetousetheMultiHarpprogramminglibraryMHLibandwriteyourownsoftware.If
theproblemisnotoneofrow-wisedatarateoverloaditmaybeeasierandmoreflexibletouseonlythemainfil-
terandtoperformthemorecomplexfilteringinsoftware.
AllotheraspectsofTTTRdatacollectionwitheventfilteringarethesameasinplainTTTRmodeasdescribed
insections5.3.1through5.3.6.Topicssuchasusingexternalmarkersorhowtousethedatafilesshouldbe
lookedupthere.
Page52