Detailed Colpitts design/operation criteria...?

[jimblair]

Hi,   I am hoping to get a recommendation of a really detailed, and accurate, Colpitts BJT oscillator design/operation tutorial/description.   I've read dozens of explanations online and on youtube, but I am struggling to find one that describes the transistor feedback.   If you have found a detailed semiconductor level description of how the oscillator design works, I'd appreciate a pointer to that source.   I am hoping for two specific explanations....(1) how does the oscillator tank incorporate the 2nd capacitor between the BJT collector and emitter, and (2) how the FM modulation works.

thanks in advance for any recommendations.

[iMo]

What about this thesis?

[bob91343]

A Colpitts oscillator relies on the voltage step-up you get when you apply a signal to the capacitive tap on the resonant circuit.

FM occurs when you vary anything in the circuit.  To make it controllable, a voltage variable capacitor is often used.