Saw stabilized oscillator with controlled pull-range
First Claim
1. An oscillator comprising in combination:
- an amplifier;
a surface acoustic wave resonator connected in a feedback relationship to the amplifier whereby the amplifier and the surface acoustic wave resonator form part of a feedback loop; and
means electrically connected to the amplifier for providing additional phase shift for the total phase shift around the feedback loop to be sufficient to cause oscillation at a predetermined frequency which is different from the center frequency of the surface acoustic wave resonator.
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Abstract
An oscillator including an active device (38), a surface acoustic wave resonator (40) connected in a feedback relationship to the active device and an impedance matching circuit is disclosed. The impedance matching circuit in one arrangement is an output impedance matching circuit including an inductor (46) connected in the feedback loop to the output of the active device. In another arrangement, the impedance matching network is an input impedance matching network including an inductor (42) connected in the feedback loop to the input of the active device. In another arrangement of the invention, a varactor diode (60) is connected in the feedback loop and is controlled by a reverse voltage which changes the capacitance of the diode, adjusting the frequency of the oscillator.
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Citations
13 Claims
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1. An oscillator comprising in combination:
- an amplifier;
a surface acoustic wave resonator connected in a feedback relationship to the amplifier whereby the amplifier and the surface acoustic wave resonator form part of a feedback loop; and means electrically connected to the amplifier for providing additional phase shift for the total phase shift around the feedback loop to be sufficient to cause oscillation at a predetermined frequency which is different from the center frequency of the surface acoustic wave resonator.
- an amplifier;
- 2. An oscillator according to claim 2 wherein the means for providing additional phase shift provides the impedance environment for determining the loaded Q of the resonator and the additional phase shift for the total phase shift around the feedback loop of substantially an integer multiple of 360°
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4. An oscillator comprising in combination:
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an active device; a surface acoustic wave resonator connected in a feedback relationship to the active device whereby the active device and the surface acoustic wave resonator form part of a feedback loop; and an output means for substantially affecting the operating loaded Q of the resonator and changing the phase shift around the feedback loop to a frequency which is different from the center frequency of the surface acoustic wave resonator. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification