Thispaperproceedsfromthegeneralcaseoftheunsymmetriclinearizedmulti-degreesoffree-dom(MDOF)systems.Byadoptingthegeneralcomplexmodaltheoryofthestatespace,theresponseanalysisforasys-temsubjectedtorandomexcitationofthesamesourceiscarriedoutusingasakindofdirectspectrumanalysismethodinfrequencydomain.Withtheinputofpowerspectraldensityfunctiongiven,theexplicitexpressionofthepowerspectraldensityfunctionmatrixoftheoutputresponsecanbeobtained.BytakingFourierinversetransform,theintegratedexpres-sionsofthecorrelationfunctionmatrixandofthespectrummomentmatrixareobtained.Comparingwiththetimedomainmethod,thismethodenjoysthemeritofvisualizationandavoidstheprocedureoftransformationfromtheobtainedre-sponsecorrelationfunctiontobesolvedfortheoutputspectrumutilizingFouriertransform.Thispaperhasextendedtheapplicationrangeofthetraditionalfrequencydomainanalysismethod.Themeansquarevaluesandvarietyofstatisticalval-uescanbeobtainedconveniently.Thismethodandthetimedomainmethodaredifferentinapproachbutequallysatisfac-toryintheirresults.
