Patent ID: 7180382
Filing Date: 2007-02-20
Classification: H03B

Abstract:
1. A controlled crystal oscillator comprising: a first crystal having first and second terminals; a transistor having a base, the base being coupled to said first crystal to the first terminal to provide positive feedback, using a feedback loop, for generating an output oscillatory signal; a voltage divider having at least one capacitor which directly connects an emitter of the transistor to the base, the voltage divider being included in the feedback loop to permit feedback to maintain oscillation; a variable reactance coupled to said first crystal at the second terminal for producing a change in a frequency of said oscillatory signal when a corresponding change in said variable reactance occurs; a first inductance coupled in a resonant circuit that includes said variable reactance and said first crystal having a value selected to provide a pulling range of at least 0.4% with respect to said frequency of said oscillatory signal, and a second crystal coupled to said first crystal via said first inductance and included in said resonant circuit.