| 摘要 |
PURPOSE:To attain stable oscillation over a wide frequency range, by adding a series circuit of a varactor diode and a capacitor to a clapping capacitor of a modified Colpitts oscillating circuit. CONSTITUTION:The varactor diode D1 and a DC blocking capacitor C5 are connected at a connecting point P mutually. The series circuit consisting of a varactor diode D3 and a DC blocking capacitor C11 is added between this connecting point P and a point where a feedback capacitor C2 is connected to the clapping capacitor C4. A DC voltage to the diodes D1, D3 is supplied from a common terminal VT. Through forming like this, the effect of the Q of a tank circuit and the resonance impedance based on the capacitance change of the diode D1 on the intensity of the oscillation is compensated. Thus, stable oscillation is attained over a wide frequency range.
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