buddypoor
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Hi uu@uk,
of course, I agree with all the arguments WAVE has listed. But I´m not sure if they are the reason of your amplitude problem. Mostly, these parasitic effects cause frequency shifts. But there remains one important question: Is your output sinusoidal or rectangular ? Quote: ...can the simulator have different amplitude value for different runs? since I run the transient simulation, the results always give me the same amplitude. That´s normal, because there is no reason for the simlator to calculate in a different way. It uses some initial conditions to arrive at a certain amplitude,
usually the xtal osc has a automation gain control circuit to manage the current after the xtal osc settles. I am not sure whether this is the limiting circuit you are talking about.
What do you mean with "manage the current" ? When I mention a limiting mechanism I mean, of course, a circuitry which is non-linear and brings the poles from the right hand s-plane back to the Im axis (or at least in the vicinity) when the amplitude increases. Such a amplitude or gain control device is necessary in each harmonic oscillator circuit. In some cases this is established by hard limiting at the power supply rails. But then, the signal is distorted.
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