pspice PSpice_ch13

PSPICE计算机仿真 SimulationProgramwithIntegratedCircuitEmphasis CH13 FOURIERSERIES傅立叶级数 Decay 衰减 13 1PulsedSources Thepulseparametersare V1initialvalue volts V2pulsedvalue volts TDdelaytime seconds TRrisetime seconds TFfalltime seconds PWpulsewidth seconds PERperiod seconds 13 2FourierAnalysis Example22illustratesapulsedvoltagesource thePSpicecomputationoftheFourierseriescoefficients andtheProbecomputationoftheFouriertransformcoefficients Example22 SupposethatthepulsedwaveformshowninFig 117aisinputtotheRCcircuitshowninFig 117b UseaFourierseriesanalysisoftheinputwaveformtopredictthefrequencycontentoftheoutputwaveformfortwovaluesofC 1uFand10uF ThenusetheFouriertransformmodeinProbetoconfirmthePSpiceanalysisandtodisplaythefrequencyspectragraphically Solution WebeginbycomputingtheFourierseriescomponentsforthepulsedvoltagesignalshowninFig 117a Notethatthiswaveformhastwopropertiesofsymmetry oddsymmetryandhalf wavesymmetry ThesesymmetrypropertiestellusseveralthingsabouttheFouriercoefficients Thedccomponentis0 TheFourierserieshasonlysineterms theancoefficientsare0forallvaluesofn Onlytheoddsinetermsarenonzero thebncoefficientsare0forevenn Becauseoftheformofthean sandthebn s theFouriercoefficientsexpressedinmagnitudeandphase angleformare Fig 118Sch Fig 119VpluseProperty Fig 120setting Fig 120a Fig 121output Maybewrong Fig 122Probe Trace Fourier Fig 123a Plot axissettings Fig 123b Fig 1