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发表于 2012-4-28 07:47:59
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Varactor is nonlienar cap and varies with the amplitude (waveform) across it, and that is the reason for AM-FM conversion. For the oscillation frequency, the "averaging effective" capacitance, rather than the small signal capacitance, matters. You can apply a sine or square waveform at about the resonance frequency on the varactor and run PSS, then run PAC to get the effective capacitance. Typically, larger voltage amplitude results in smaller effective capacitance. |
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