标签: pll-prob

PLL-Prob&SolsPLLProblemsandSolutions(9/6/03)PLLPROBLEMSANDSOLUTIONSPage1Problem1Rs=5.3Cs=30fFSolveforandevaluatetheseriesandparallelresonanceLs=8.4mHfrequenciesofthecrystalwhosemodelisshown.ItisCp=6pFsuggestedtomakeappropriateassumptionsastheexactCrystalSU03H01P1frequenciesaredifficulttoachieve.SolutionSolvingtheexactfrequenciesforthisproblemisverychallenging.Itisbettertoassumethatseriesresonance(minimumimpedance)willoccurapproximatelywhentheimpedanceofCscancelstheimpedanceofLs.Thisgivesseriesresonanceas1ωs2=LCss→fs=1≈10.026MHz2πLsCsTheparallelresonancecanbeapproximatedbyassumingthatitwilloccurclosetothefrequencywhentheimpedanceoftheseriesbranchequalsthenegati……