Exfo EXpert IPTV Test Tools (FTB-200v2) Manuale Utente Scaricare il pdf (Pagina 60)

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VQmon/HDcalculatesqualitymetricsintheseburstandgapstates,andthencombinesthem

togeneratetheoverallqualityscoreonuserexperi ence.Thesecalculationsarebasedonthe

resultsofnumerouss ubjectivevoice/videoqualityanalysisteststhatindicatethereisnotan

instantaneouschangeinperceivedqualitywhenatransitionbetw

eenthegapandburststates

occurs,butratherthattheperceivedqualityexponentially“decays”fromonelevelto

another.Forexample,a100‐millisecondburstof“noise”ismuchlessannoyingthana10

secondburstof“noise”.

Figure2‐8illustratestheVQmon4‐stateMarkovmodel.TheVQmon4‐stateMarkovmodelis

define

dashavingthefollowingstatesandassociatedtransitions:

Table2‐1.VQmon4‐stateMarkovmodelstatetransitiondescriptions

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1 2 ... 55 56 57 58 59 60 61 62 63 64 65 ... 81 82

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Exfo EXpert IPTV Test Tools (FTB-200v2) Manuale Utente Pagina 60