| 摘要 |
<p>D-22,470 FREQUENCY MODULATED FET OSCILLATOR by Volker B. Weise An FM oscillator of the Colpitts type having one feedback capacitor of the frequency-determining tank circuit connected across the drain-and-source electrodes of a JFET, the other feedback capacitor being connected between the source and a ground reference potential. A bypass capacitor is electrically connected between the FET gate electrode and ground for electrically connecting the FET gate-to-source junction capacitance across the other feedback capacitor at the resonant frequency of the tank. A DC bias voltage is established across the gate-to-source junction during quiescent conditions so that a modulation voltage applied to the gate causes the gate-to-source voltage, and thus the associated junction capacitance, to vary so as to produce a relatively linear change in the resonant frequency of the tank as a function of the modulation voltage.</p> |
