| 摘要 |
A voltage-controlled oscillating circuit includes a differential amplifying circuit connected to a resonant element such as a quartz crystal element. The differential amplifying circuit includes first and second input terminals connected to the resonant element and also connected respectively to first and second voltage-controlled capacitors. The differential output terminals of the differential amplifying circuit are connected respectively to first and second emitter follower circuits. The output signal of the first emitter follower circuit is fed back to the second input terminal through a third capacitor and a third voltage-controlled capacitor, and the output signal of the second emitter follower circuit is fed back to the second input terminal through a fourth capacitor and a fourth voltage-controlled capacitor. A control voltage is applied to each of the voltage-controlled capacitors.
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