US3950713A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acoustic wave devices
Assignee: National Research Development Corp UK
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Filing: 1974-02-14
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Granted: 1976-04-13
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Expires: 1994-02-14
Abstract
Abstract A surface acoustic wave delay line for use with an amplifier to form an oscillator has the spacing of its two transducers arranged to provide the desired mode of oscillation and the frequency responses of one or both transducers arranged to suppress unwanted moles of oscillation. Various transducers configuration are provided to reduce reflection problems between and within the transducers. The oscillator may be frequency modulated.
Inventors
- 👤 Meirion Francis Lewis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:40
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/02535; H03H9/02818; H03B; H03B5/00; H03B5/30; H03B5/32; H03B5/326; H03H9/125; H03H9/145; H03H9/14517; H03H9/14526; H03H9/14544; H03H9/1455; H03H9/30; H03H9/42
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
89 words
An acoustic wave device comprising: a substrate able to support acoustic waves; an interdigital comb input transducer for launching acoustic waves in the substrate; an interdigital comb output transducer for detecting and receiving acoustic waves launched by the input transducer; wherein one of the transducers is of greater effective length than the other transducer, and wherein the length of the longer transducer is related to the separation of the transducers so as to produce frequency responses which suppress unwanted modes of acoustic frequency oscillation and allow only one mode.
Claim 2
Dependent Claim
89 words
An acoustic wave device comprising: a substrate able to support acoustic waves; an interdigital comb input transducer for launching acoustic waves in the substrate; an interdigital comb output transducer for detecting and receiving acoustic waves launched by the input transducer; wherein one of the transducers is of greater effective length than the other transducer, and wherein the length of the longer transducer is related to the separation of the transducers so as to produce frequency responses which suppress unwanted modes of acoustic frequency oscillation and allow only one mode.
Claim 3
Dependent Claim
27 words
A device according to claim 1 wherein the path length between the centres of the two transducers is equal to the effective length of the longer transducer.
Claim 4
Dependent Claim
22 words
A device according to claim 1 wherein at least the longer transducer has finger pairs arranged in groups with spaces between groups.
Claim 5
Dependent Claim
23 words
A device according to claim 3 wherein the groups of finger pairs in at least the longer transducer are equi-spaced from one another.
Claim 6
Dependent Claim
42 words
A device according to claim 4 wherein the pathlength between the centres of both transducers equals the sume of the effective length of the longer transducer and the length between centres of groups of adjacent finger pairs in the said longer transducer.
Claim 7
Dependent Claim
35 words
A device according to claim 5 wherein the shorter transducer has a single group of finger pairs of effective length equal to the length between centres of groups of finger pairs in the longer transducer.
Claim 8
Dependent Claim
31 words
A device according to claim 1 wherein at least the longer transducer has finger pairs arranged in groups equi-spaced apart with quarter wave reflectors arranged between the groups of finger pairs.
Claim 9
Dependent Claim
116 words
An acoustic wave oscillator comprising an amplifier and an acoustic wave delay line connected to form a feedback loop to the amplifier, the acoustic wave delay line comprising: a substrate able to support acoustic waves, an interdigital comb input transducer for launching acoustic waves in the substrate, an interdigital comb output transducer for detecting and receiving acoustic waves launched by the input transducer, wherein one of the transducers is of greater effective length than the other transducer, and wherein the length of at least the longer transducer is related to the separation of the transducers so as to produce frequency responses which suppress unwanted modes of acoustic frequency oscillation and allow only one mode of oscillation.
Claim 10
Dependent Claim
116 words
An acoustic wave oscillator comprising an amplifier and an acoustic wave delay line connected to form a feedback loop to the amplifier, the acoustic wave delay line comprising: a substrate able to support acoustic waves, an interdigital comb input transducer for launching acoustic waves in the substrate, an interdigital comb output transducer for detecting and receiving acoustic waves launched by the input transducer, wherein one of the transducers is of greater effective length than the other transducer, and wherein the length of at least the longer transducer is related to the separation of the transducers so as to produce frequency responses which suppress unwanted modes of acoustic frequency oscillation and allow only one mode of oscillation.
References Cited (Backward Citations)
US3766496A
Cited
US3805189A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-04-13 | 1979-10-13 | 1980-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-13 | 1983-10-13 | 1984-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-13 | 1987-10-13 | 1988-04-13 | $7700.00 | Window Closed / Lapsed |