Patent ID: 6172574
Filing Date: 2001-01-09
Classification: H03B

Abstract:
A voltage-controlled quartz crystal oscillator, including an oscillation transistor, a base of which is connected to a first terminal of a quartz crystal and an emitter of which is connected, via a first capacitor, to a second terminal of the quartz crystal connected to a first supply terminal, and including an active circuit introducing a variable capacitance between the base and the emitter of the oscillation transistor, the active circuit being voltage-controlled, wherein the active circuit is formed by a structure with a differential control, receiving a modulating signal,said active circuit comprising at least a first differential transistor pair including at least a first transistor and a second transistor and means coupling said first differential transistor pair to said oscillation transistor to provide a variable capacitance between the base and emitter of the oscillation transistor.