US3662293A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acoustic-wave transmitting device
Assignee: Zenith Electronics LLC
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Filing: 1971-03-17
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Granted: 1972-05-09
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Expires: 1991-03-17
Abstract
Abstract Acoustic-surface-wave transducers are spaced apart on the surface of a wave-propagating substrate. In response to an input signal, one transducer launches surface waves toward the other which responds thereto by developing an output signal. Without more, an undesired time-delayed output signal or ''''ghost'''' may be produced by reason of surface waves reflected back to the input transducer from the output transducer. In order to inhibit the development of ghosts, a plurality of surface discontinuities, such as grooves, are formed in the wave-propagating surface alongside the output transducer. These grooves also reflect surface waves and they are spaced from the input transducer by such a distance that surface waves reflected from the grooves reach one of the transducers in a predetermined time and phase relation with respect to an acoustic surface wave reflected by the output transducer to cause cancellation so that the development of ghosts is inhibited.
Inventors
- 👤 Adrian J De Vries
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:14
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/02535; H03H9/02818; H03H9/02842; H03H9/02614; H03H9/02622; H03H9/02637; H03H9/02653
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
219 words
An acoustic-wave transmitting device comprising: an acoustic-wave propagating medium; first transducer means responsive to an input signal for launching in said medium acoustic surface waves of a predetermined wavelength; second transducer means responsive to said acoustic sUrface waves for developing a desired output signal, said second transducer means also being a partial reflector of acoustic surface waves so that a portion of said launched waves is returned to said first transducer means where it is reflected a second time and redirected to said second transducer means where it develops an undesired output signal which is a substantial replica of, although reduced in amplitude and delayed in time with respect to, said desired output signal; a plurality of substantially similar surface discontinuities in said medium disposed across the wave propagation path of an acoustic surface wave launched by said first transducer means with a center-to-center spacing along said path of one-half said wavelength, said surface discontinuities being reflective of acoustic surface waves and having a spacing along said propagation path to cause the acoustic surface wave reflected by said surface discontinuities to reach one of said transducer means in a predetermined time and phase relation with respect to an acoustic surface wave reflected by said second transducer means to at least partially inhibit the development of said undesired output signal.
Claim 2
Dependent Claim
219 words
An acoustic-wave transmitting device comprising: an acoustic-wave propagating medium; first transducer means responsive to an input signal for launching in said medium acoustic surface waves of a predetermined wavelength; second transducer means responsive to said acoustic sUrface waves for developing a desired output signal, said second transducer means also being a partial reflector of acoustic surface waves so that a portion of said launched waves is returned to said first transducer means where it is reflected a second time and redirected to said second transducer means where it develops an undesired output signal which is a substantial replica of, although reduced in amplitude and delayed in time with respect to, said desired output signal; a plurality of substantially similar surface discontinuities in said medium disposed across the wave propagation path of an acoustic surface wave launched by said first transducer means with a center-to-center spacing along said path of one-half said wavelength, said surface discontinuities being reflective of acoustic surface waves and having a spacing along said propagation path to cause the acoustic surface wave reflected by said surface discontinuities to reach one of said transducer means in a predetermined time and phase relation with respect to an acoustic surface wave reflected by said second transducer means to at least partially inhibit the development of said undesired output signal.
Claim 3
Dependent Claim
26 words
A device as defined in claim 1 in which said surface discontinuities comprise a series of parallel arranged grooves formed in the surface of said medium.
Claim 4
Dependent Claim
22 words
A device as defined in claim 2 in which said grooves individually define elongated rectangular slots in the surface of said medium.
Claim 5
Dependent Claim
19 words
A device as defined in claim 2 in which said grooves constitute undulations in the surface of said medium.
Claim 6
Dependent Claim
98 words
A device as defined in claim 1 in which said first transducer means includes a pair of interleaved combs of conductive electrodes disposed on the propagating surface of said medium with the electrodes of said combs spaced apart by one-half said wavelength, and in which said second transducer means includes another pair of interleaved combs of conductive electrodes disposed on said surface in spaced relation to said first pair of combs with the electrodes in said other pair of combs having the same inter-electrode spacing but a shorter length than said electrodes of said first pair of combs.
Claim 7
Dependent Claim
55 words
A device as defined in claim 5 in which said pair of combs of said first and second transducer means are spaced apart by a predetermined distance and in which said grooves are effectively spaced from said combs of said first transducer means by a distance differing from said predetermined distance by one-fourth said wavelength.
Claim 8
Dependent Claim
48 words
A device as defined in claim 5 in which said pair of combs of said second transducer means has a spacing from said first transducer means which is greater than the effective spacing of said grooves from said first transducer means by a distance of one-fourth said wavelength.
Claim 9
Dependent Claim
28 words
A device as defined in claim 5 in which the length of the electrodes in said second transducer means is substantially greater than the length of said grooves.
Claim 10
Dependent Claim
64 words
A device as defined in claim 1 in which said first transducer means launches acoustic surface waves along a path that extends across substantially the entire width of said substrate, in which said second transducer means is disposed in one portion of said path while said surface discontinuities are disposed in a separate portion of said path disposed laterally from said one portion thereof.
References Cited (Backward Citations)
US2965851A
Cited
US3522557A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-09 | 1975-11-08 | 1976-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-09 | 1979-11-08 | 1980-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-09 | 1983-11-08 | 1984-05-09 | $7700.00 | Window Closed / Lapsed |