US4570132A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low noise multiple crystal-controlled oscillator
Assignee: United States Department of the Air Force
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Filing: 1984-08-29
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Granted: 1986-02-11
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Expires: 2004-08-29
Abstract
Abstract An oscillator circuit utilizing multiple (two) quartz crystal resonators as the frequency controlling elements in a novel circuit arrangement. The use of two crystal units increases the oscillator circuit signal transmission group delay by a factor of 2 to 3 and effects an estimated 6 dB reduction in oscillator output signal phase noise sideband level at carrier offset frequencies less than the resonator half-bandwidths. The degree of resonator tracking required is made practical with the use of temperature controlled SC-cut resonators. In addition, the oscillator circuit is configured so that equal, correlated output signal currents can be extracted from each resonator through individual load circuits, thereby increasing available oscillator output signal amplitude by 2:1 and reducing the net effect of uncorrelated load circuit additive noise by 3 dB.
Inventors
- 👤 Michael M. Driscoll
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:00
CPC Classifications
H; H03; H03B; H03B27/00; H03B5/00; H03B5/30; H03B5/32; H03B2200/00; H03B2200/0014; H03B2200/0018; H03B5/02; H03B5/04
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
180 words
A low noise crystal controlled oscillator comprising: first and second transistors each having a base, an emitter and a collector; a first phase shift circuit coupled between the collector of said first transistor and the base of said second transistor; a second phase shift circuit coupled between the collector of said second transistor and the base of said first transistor; a reference terminal; third and fourth transistors each having a base coupled to said reference terminal, an emitter and a collector; a first crystal resonator unit coupled between the emitter of said first transistor and the emitter of said third transistor; a second crystal resonator unit coupled between the emitter of said second transistor and the emitter of said fourth transistor; a signal combiner having a pair of input terminals and an output terminal; first means for coupling the collector of said third transistor to one of said pair of input terminals of said signal combiner; and second means for coupling the collector of said fourth transistor to the other one of said pair of inputs of said signal combiner.
Claim 2
Dependent Claim
180 words
A low noise crystal controlled oscillator comprising: first and second transistors each having a base, an emitter and a collector; a first phase shift circuit coupled between the collector of said first transistor and the base of said second transistor; a second phase shift circuit coupled between the collector of said second transistor and the base of said first transistor; a reference terminal; third and fourth transistors each having a base coupled to said reference terminal, an emitter and a collector; a first crystal resonator unit coupled between the emitter of said first transistor and the emitter of said third transistor; a second crystal resonator unit coupled between the emitter of said second transistor and the emitter of said fourth transistor; a signal combiner having a pair of input terminals and an output terminal; first means for coupling the collector of said third transistor to one of said pair of input terminals of said signal combiner; and second means for coupling the collector of said fourth transistor to the other one of said pair of inputs of said signal combiner.
Claim 3
Dependent Claim
25 words
Apparatus as defined in claim 1 wherein said first crystal resonator unit and said second crystal resonator unit have substantially the same series resonance frequency.
Claim 4
Dependent Claim
23 words
Apparatus as defined in claim 2 wherein said first crystal resonator unit and said second crystal resonator unit are each SC-cut quartz crystals.
Claim 5
Dependent Claim
15 words
Apparatus as defined in claim 3 wherein said signal combiner is a signal power combiner.
Claim 6
Dependent Claim
15 words
Apparatus as defined in claim 3 wherein said signal combiner is a signal frequency combiner.
Claim 7
Dependent Claim
23 words
Apparatus as defined in claim 3 and further including first and second inductors shunting said first and said second crystal resonator units respectively.
Claim 8
Dependent Claim
31 words
Apparatus as defined in claim 3 wherein said first phase shift circuit and said second phase shift circuit each exhibit 0 degrees phase shift at the operating frequency of said oscillator.
Claim 9
Dependent Claim
31 words
Apparatus as defined in claim 3 wherein said first phase shift circuit and said second phase shift circuit each exhibit 180 degrees phase shift at the operating frequency of said oscillator.
Claim 10
Dependent Claim
61 words
Apparatus as defined in claim 3 and further comprising: a first parallel tank circuit resonant at the operating frequency of said oscillator coupled between the emitter of said first transistor and said reference terminal; and a second parallel resonant tank circuit resonant at the operating frequency of said oscillator coupled between the emitter of said second transistor and said reference terminal.
Claim 11
Dependent Claim
90 words
Apparatus as defined in claim 3 wherein said first means comprises: an output matching network, a frequency doubler circuit and a frequency doubler output filter serially coupled between the collector of said third transistor and said one of said pair of input terminals of said signal combiner; and wherein said second means comprises: an output matching network, a frequency doubler circuit and a frequency doubler output filter serially coupled between the collector of said fourth transistor and said other one of said pair of input terminals of said signal combiner.
Claim 12
Dependent Claim
16 words
Apparatus as defined in claim 7 wherein said signal combiner is a 180 degree signal combiner.
Claim 13
Dependent Claim
16 words
Apparatus as defined in claim 8 wherein said signal combiner is a 0 degree signal combiner.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-10 | 1989-08-12 | 1990-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-10 | 1993-08-12 | 1994-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-10 | 1997-08-12 | 1998-02-11 | $7700.00 | Window Closed / Lapsed |