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US 5,329,256 AGranted
Tunable oscillator having a non-reflective saw resonator
AssigneeMotorola, Inc.
InventorRobert J. Higgins, Jr.
Life of this patent
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Abstract
A tunable oscillator circuit (200) includes surface acoustic wave transducer (303) disposed on a piezoelectric substrate (301) having a high SAW coupling coefficient. The SAW transducer is (303) non-reflective and self-resonant comprising a pair of electrodes with interdigitated fingers. A tuning mechanism, such as a varactor, is coupled across the transducer allowing for output frequency tuning of the oscillator circuit.
Claims23
A tunable oscillator circuit for providing an output frequency, comprising:
- a non-reflective, self-resonant SAW resonator including:
- a piezoelectric substrate;
- and
- a SAW transducer portion disposed on said piezoelectric substrate having at least one pair of electrodes with interdigitated open-ended fingers, wherein surface acoustic waves emanating from said SAW transducer are not reflected;
- and
- capacitive tuning means coupled across said resonator for tuning said output frequency.
3 more elements
A voltage controlled oscillator circuit for providing an output frequency, comprising:
- a tuning port for receiving a tuning signal;
- tuning means for tuning said output frequency in response to said tuning signal;
- and
- a non-reflective, self-resonant SAW resonator coupled to said tuning means including:
- a piezoelectric substrate;
- and
- a SAW transducer portion disposed on said piezoelectric substrate having at least one pair of electrodes with interdigitated open-ended fingers, wherein surface acoustic waves emanating from said SAW transducer are not reflected.
4 more elements
A frequency synthesizer;
- comprising:
- a phase locked loop including a voltage controlled oscillator circuit for providing an output frequency, comprising:
- a tuning port for receiving a control signal from said phase locked loop;
- tuning means for tuning said output frequency in response to said control signal;
- and
- a non-reflective, self resonant SAW resonator coupled to said tuning means including:
- a piezoelectric substrate having a coupling coefficient exceeding 2%;
- and
- a SAW transducer portion disposed on said piezoelectric substrate having at least one pair of electrodes with interdigitated open-ended fingers, wherein surface acoustic waves emanating from said SAW transducer are not reflected.
6 more elements
A radio, comprising:
- communication means for communicating communication messages;
- and
- a tunable oscillator circuit for providing an output frequency usable by said communication means, comprising:
- a non-reflective, self-resonant SAW resonator including:
- a piezoelectric substrate;
- and
- a SAW transducer portion disposed on said piezoelectric substrate having at least one pair of electrodes with interdigitated open-ended fingers, wherein surface acoustic waves emanating from said SAW transducer are not reflected;
- and
- capacitive tuning means coupled across said electrodes for tuning said output frequency.
6 more elements
Dependencies are inferred from the claim text.