关键公式
\[f_{osc} = \frac{1}{2\pi RC}\;\text{(文氏桥)} \qquad f_{osc} = \frac{1}{2\pi RC\sqrt{6}}\;\text{(三节等值RC移相)}\]
\[C_{eq}=\frac{C_1C_2}{C_1+C_2},\qquad f_{osc} = \frac{1}{2\pi\sqrt{LC_{eq}}}\;\text{(Colpitts谐振频率)}\]
\[|A\beta|>1\;\text{起振},\qquad |A\beta|=1\;\text{维持稳态},\qquad \angle A\beta=0^\circ\;\text{或}\;360^\circ\]