US3855548A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ultra high frequency single mode oscillation controlled by a surface acoustic wave crystal
Assignee: Boeing North American Inc
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Filing: 1973-10-18
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Granted: 1974-12-17
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Expires: 1993-10-18
Abstract
Abstract An ultra high frequency crystal oscillator includes an amplifier and a surface acoustic wave device connected in a feedback path around the amplifier. The surface acoustic wave device is the primary frequency control component of the oscillator and comprises a piezoelectric material having input and output transducers disposed thereon. Each of the transducers comprises an interdigitated electrode structure in which the separation between adjacent electrodes is a predetermined function of the acoustic wave length of a signal having a desired oscillation frequency. One of the transducers is comprised of a plurality of taps the spacing of which is a predetermined function of the length of the other transducer. In addition to the surface acoustic wave device, the feedback path of the amplifier may include, inter alia, power splitters, reactance compensating networks and a phase adjusting network for making small adjustments in the frequency of oscillation of the oscillator.
Inventors
- 👤 A Nandi
- 👤 S Costanza
- 👤 C Wheatley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:34
CPC Classifications
H; H03; H03B; H03B5/00; H03B5/30; H03B5/32; H03B5/326
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
101 words
An oscillator comprising an amplifier having a surface acoustic wave delay line in a feedback path, wherein the delay line comprises: a substrate capable of supporting surface acoustic waves; and first and second transducers each disposed in coupling relation to said substrate; said first transducer comprised of a plurality of taps connected in parallel, each said tap comprising an interdigital transducer; said taps being spaced center-to-center by an integral multiple of the wave length of a desired oscillation frequency so that each tap will produce an in-phase output signal at said desired frequency; and said second transducer comprising an interdigital transducer.
Claim 2
Dependent Claim
101 words
An oscillator comprising an amplifier having a surface acoustic wave delay line in a feedback path, wherein the delay line comprises: a substrate capable of supporting surface acoustic waves; and first and second transducers each disposed in coupling relation to said substrate; said first transducer comprised of a plurality of taps connected in parallel, each said tap comprising an interdigital transducer; said taps being spaced center-to-center by an integral multiple of the wave length of a desired oscillation frequency so that each tap will produce an in-phase output signal at said desired frequency; and said second transducer comprising an interdigital transducer.
Claim 3
Dependent Claim
200 words
The oscillator of claim 1 wherein: each interdigital transducer comprises alternate first and second electrodes wherein each first electrode of a given transducer is connected to a first connecting conductor and each second electrode of the given transducer is connected to a second connecting condUctor: the first electrodes of said taps of said first transducer are spaced from the adjacent first electrodes of the same tap by the wave length of said desired frequency; the second electrodes of said taps of said first transducer are spaced from the adjacent second electrodes of the same tap by the wave length of said desired frequency; adjacent first and second electrodes of the same tap of said first transducer are spaced from each other by one-half of the wave length of said desired frequency; the first electrodes of the second transducer are spaced from the adjacent first electrodes by the wave length of the desired frequency; the second electrodes of the second transducer are spaced from the adjacent second electrodes by the wave length of the desired frequency; and adjacent first and second electrodes of the second transducer are spaced from each other by one-half of the wave length of the desired frequency.
Claim 4
Dependent Claim
15 words
The oscillator of claim 2 wherein each electrode is substantially one-quarter wave length in width.
Claim 5
Dependent Claim
23 words
The oscillator of claim 1 wherein said second transducer has many more electrodes than any tap and is much longer than any tap.
Claim 6
Dependent Claim
17 words
The apparatus of claim 4 wherein said taps are separated by the length of said second transducer.
Claim 7
Dependent Claim
21 words
The apparatus of claim 5 wherein said first transducer is an output transducer and said second transducer is an input transducer.
Claim 8
Dependent Claim
40 words
The apparatus of claim 1 wherein the tap of said first transducer which is nearest the second transducer is spaced from the second transducer by a distance of between 3 and 5 times the length of said second transducer inclusive.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |