Hello,

I have a general question about the operational principle of an LC oscillator, connected in the configuration shown. Here, the resonance frequency (and hence the frequency of oscillation) is determined by the LC tank.

My question: Assuming this is connected in a positive feedback configuration, what would be the effect of phase shift between the input and output? That is, if the amplifier has, say, a propagation delay, what would be its effect on the oscillation impedance (and thus, the amplitude of oscillations)?

 

Any other phase than 0° is basically a form of negative feedback, the amplifier will try to find a freq that offers 0° shift. Only no phase shift is positive feedback.