buddypoor
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1.) The quality factor you have mentioned is defined with respect to the parasitic phase shift introducd by the amplifier - for example plus two degrees. In this case the oscillating frequency is shifted until the passive network introduces minus two degrees in order to fulfill the oscillation condition. When the phase slope is large the amplifier phase shift effect causes only a small frequency shift. This explains the proportionality between the phase slope and the definition of the so called "quality factor". 2.) However, this quality factor applies ONLY to oscillators which consist of frequency selective networks and an amplifier (two-port oscillators); thus, it applies NOT for negative resistance oscillators as well as integrator loops. 3.) Therefore, this factor has only a limited value and cannot be used to compare two-port oscillators with other types like neg. R or integrator type oscillators.
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