The dispersivephasevelocityofawavepropagatingthroughasystemisanimportantparameterand
carriesvaluableinformationinnon-destructivetestsrelatedtomulti-layeredsystemssuchasasoilsite.
The dispersivephasevelocityofawavecanbeestimatedusingthephasespectrum,whichiseasily
evaluatedthroughthecrosspowerspectrum.However,thephasespectrumasobtainedusingthecross
powerspectrumissensitivetobackgroundnoise,whichalwaysexistsinthefield.Thiscauses
difficultiesinthedeterminationofthedispersivephasevelocities.Inthispaper,anewmethodto
evaluatethephasespectrumusingtheharmonicwavelettransformisproposed.Theintroduced
method cansuccessfullyremovebackgroundnoiseeffects.Toevaluatethevalidityofthismethod,
numericalsimulationsofmulti-layeredsystemswereperformed.Phasespectradeterminedbythe
suggested methodwerefoundtobeingoodagreementwiththeactualphasespectraunderconditions
characterized byheavybackgroundnoise.Thisshowsthepotentialoftheproposedmethod.
