US3596211A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surface-wave filter reflection cancellation
Assignee: Zenith Electronics LLC
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Filing: 1967-11-06
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Granted: 1971-07-27
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Expires: 1987-11-06
Abstract
Abstract Undesired time-delayed and reduced-amplitude output signal components or ''''ghosts,'''' due to reflected surface waves arriving at the output transducer of an acousto-electric surface-wave filter, are inhibited or cancelled by providing an additional transducer suitably located to reflect compensating surface waves which arrive at either the input transducer or the output transducer in appropriate amplitude and phase to nullify the effect of the undesired surface waves. The amplitude of the compensating surface waves is controlled by the configuration of the additional transducer and the magnitude of its associated external load impedance.
Inventors
- 👤 Fleming Dias
- 👤 Adrian J De Vries
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:16
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/02535; H03H9/02818; H03H9/02842; H03H9/125; H03H9/145; H03H9/14597
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
241 words
An acousto-electric surface-wave signal-translating device comprising: a solid-state acoustic-surface-wave-propagating medium; an input surface-wave transducer coupled to said wavepropagating medium at a first location and responsive to an input signal of a predetermined center frequency for propagating a first acoustic-surface-wave signal along a predetermined path in said medium; an output surface-wave transducer coupled to said medium at a second location on said predetermined path and spaced from said first location by a predetermined distance along said path, said output transducer being responsive to said first acousticsurface-wave signal to develop a desired electrical output signal but also initiating a second acoustic-surface-wave signal comprising a reduced-amplitude reflection of said first acoustic-surface-wave signal and said output transducer being subject to generate a spurious output signal component attributed to said reflection; means including an additional surface-wave transducer coupled to said medium at a location spaced from said first and second locations and responsive to one of said acoustic-surface-wave signals in said medium to propagate a compensating acousticsurface-wave signal along a path traversing one of said input and output transducers, said compensating acoustic-surface-wave signal being substantially in counterphase with said second acoustic-surface-wave signal at said one transducer; and means including a load impedance coupled to said additional transducer for establishing the amplitude of said compensating acoustic-surface-wave signal at said one transducer at a level effectively equal to the amplitude of said second acousticsurface-wave signal at said one transducer, whereby said spurious output signal component is effectively eliminated.
Claim 2
Dependent Claim
241 words
An acousto-electric surface-wave signal-translating device comprising: a solid-state acoustic-surface-wave-propagating medium; an input surface-wave transducer coupled to said wavepropagating medium at a first location and responsive to an input signal of a predetermined center frequency for propagating a first acoustic-surface-wave signal along a predetermined path in said medium; an output surface-wave transducer coupled to said medium at a second location on said predetermined path and spaced from said first location by a predetermined distance along said path, said output transducer being responsive to said first acousticsurface-wave signal to develop a desired electrical output signal but also initiating a second acoustic-surface-wave signal comprising a reduced-amplitude reflection of said first acoustic-surface-wave signal and said output transducer being subject to generate a spurious output signal component attributed to said reflection; means including an additional surface-wave transducer coupled to said medium at a location spaced from said first and second locations and responsive to one of said acoustic-surface-wave signals in said medium to propagate a compensating acousticsurface-wave signal along a path traversing one of said input and output transducers, said compensating acoustic-surface-wave signal being substantially in counterphase with said second acoustic-surface-wave signal at said one transducer; and means including a load impedance coupled to said additional transducer for establishing the amplitude of said compensating acoustic-surface-wave signal at said one transducer at a level effectively equal to the amplitude of said second acousticsurface-wave signal at said one transducer, whereby said spurious output signal component is effectively eliminated.
Claim 3
Dependent Claim
44 words
An acousto-electric signal-translating device according to claim 1, in which said one transducer is said output transducer and elimination of said spurious output component is accomplished by the generation of a cancelling signal component by said output transducer in response to said acoustic-surface-wave signal.
Claim 4
Dependent Claim
47 words
An acousto-electric signal-translating device according to claim 1, in which said one transducer is said output transducer and the electrical signals attributable to said second signal and to said compensating signal are mutually cancelling at said input transducer so that no reflected acoustic-surface-wave reaches said output transducer.
Claim 5
Dependent Claim
33 words
An acousto-electric signal-translating device according to claim 1, in which said acoustic-surface-wave propagating medium is composed of piezoelectric material and each of said transducers comprises a pair of surface electrodes on said medium.
Claim 6
Dependent Claim
50 words
An acousto-electric signal-translating device according to claim 4, in which the surface electrodes of each pair are in the form of interleaved combs of conductive material on a common surface of said medium, with the space between adjacent teeth in each comb being substantially one wavelength at said predetermined frequency.
Claim 7
Dependent Claim
43 words
An acousto-electric signal-translating device according to claim 1, in which the spacing between said additional transducer and said one transducer differs from the spacing between said input and output transducers by substantially an odd multiple of one-fourth wavelength at said predetermined center frequency.
Claim 8
Dependent Claim
31 words
An acousto-electric signal-translating device according to claim 1, in which said load impedance coupled to said additional transducer make the characteristics of said additional transducer and said load impedance substantially resistive.
Claim 9
Dependent Claim
191 words
An acousto-electric surface wave signal-translating device comprising: an acoustic-surface-wave-propagating medium; input surface-wave trAnsducer means coupled to said medium for impressing desired acoustic surface waves on said medium and propagating them along a pair of generally parallel wave-propagating paths; output surface-wave transducer means spaced from said input transducer means, coupled to said medium at one of said paths and responsive to said desired acoustic surface waves for developing an electrical output signal; said device being subject to the generation of undesired acoustic surface waves in said medium and to the consequent development of undesired output signal components by said output transducer means in response to said undesired acoustic surface waves; and additional surface-wave transducer means spaced from said input and output transducer means, coupled to said medium at the other of said paths at a location traversed by said desired acoustic surface waves, and responsive to acoustic surface waves therein for generating additional acoustic surface waves in said medium substantially in counterphase with said undesired acoustic surface waves at one of said transducers to substantially counteract said undesired acoustic surface waves and thereby inhibit the development of said undesired output signal components.
Claim 10
Dependent Claim
191 words
An acousto-electric surface wave signal-translating device comprising: an acoustic-surface-wave-propagating medium; input surface-wave trAnsducer means coupled to said medium for impressing desired acoustic surface waves on said medium and propagating them along a pair of generally parallel wave-propagating paths; output surface-wave transducer means spaced from said input transducer means, coupled to said medium at one of said paths and responsive to said desired acoustic surface waves for developing an electrical output signal; said device being subject to the generation of undesired acoustic surface waves in said medium and to the consequent development of undesired output signal components by said output transducer means in response to said undesired acoustic surface waves; and additional surface-wave transducer means spaced from said input and output transducer means, coupled to said medium at the other of said paths at a location traversed by said desired acoustic surface waves, and responsive to acoustic surface waves therein for generating additional acoustic surface waves in said medium substantially in counterphase with said undesired acoustic surface waves at one of said transducers to substantially counteract said undesired acoustic surface waves and thereby inhibit the development of said undesired output signal components.
Claim 11
Dependent Claim
250 words
An acousto-electric surface wave signal-translating device comprising: an acoustic-surface-wave-propagating medium; input surface-wave transducer means coupled to said medium for impressing desired acoustic surface waves on said medium and propagating them along a first predetermined path; output surface-wave transducer means spaced from said input transducer means, coupled to said medium in said path and responsive to said desired acoustic surface waves for developing an electrical output signal; said device being subject to the generation of undesired acoustic surface waves in said medium by said output transducer means, coupled to said medium in said path and responsive to said desired acoustic surface waves for developing an electrical output signal; said device being subject to the generation of undesired acoustic surface waves in said medium by said output transducer means and their propagation concurrently therefrom along two spaced paths in said medium extending to said input transducer means and to said additional transducer means, respectively, and to the consequent development of undesired output signal components by said output transducer means in response to said undesired acoustic surface waves; and additional surface-wave transducer means spaced from said input and output transducer means, coupled to said medium at a location traversed by said desired acoustic waves, and responsive to acoustic surface waves therein for generating additional acoustic surface waves in said medium substantially in counterphase with said undesired acoustic surface waves at one of said transducers to substantially counteract said undesired acoustic surface waves and thereby inhibit the development of said undesired output signal components.
Claim 12
Dependent Claim
250 words
An acousto-electric surface wave signal-translating device comprising: an acoustic-surface-wave-propagating medium; input surface-wave transducer means coupled to said medium for impressing desired acoustic surface waves on said medium and propagating them along a first predetermined path; output surface-wave transducer means spaced from said input transducer means, coupled to said medium in said path and responsive to said desired acoustic surface waves for developing an electrical output signal; said device being subject to the generation of undesired acoustic surface waves in said medium by said output transducer means, coupled to said medium in said path and responsive to said desired acoustic surface waves for developing an electrical output signal; said device being subject to the generation of undesired acoustic surface waves in said medium by said output transducer means and their propagation concurrently therefrom along two spaced paths in said medium extending to said input transducer means and to said additional transducer means, respectively, and to the consequent development of undesired output signal components by said output transducer means in response to said undesired acoustic surface waves; and additional surface-wave transducer means spaced from said input and output transducer means, coupled to said medium at a location traversed by said desired acoustic waves, and responsive to acoustic surface waves therein for generating additional acoustic surface waves in said medium substantially in counterphase with said undesired acoustic surface waves at one of said transducers to substantially counteract said undesired acoustic surface waves and thereby inhibit the development of said undesired output signal components.
Claim 13
Dependent Claim
194 words
An acousto-electric surface wave signal-translating device comprising: an acoustic-surface-wave-propagating medium; input surface-wave transducer means coupled to said medium for impressing desired acoustic surface waves on said medium; output surface-wave transducer means spaced from said input transducer means, coupled to said medium and responsive to said desired acoustic surface waves for developing an electrical output signal; said device being subject to the generation of undesired acoustic surface waves in said medium and to the consequent development of undesired output signal components by said output transducer means in response to said undesired acoustic surface waves; and additional surface-wave transducer means spaced from said input and output transducer means, coupled to said medium at a location traversed by said desired acoustic surface waves, and responsive to acoustic surface waves therein for generating additional acoustic surface waves in said mEdium substantially in counterphase with said undesired acoustic surface waves at one of said transducers, and further including a load impedance coupled to said additional transducer means for establishing the amplitude and phase of said additional acoustic surface waves to substantially counteract said undesired acoustic surface waves and thereby effectively inhibit the development of said undesired output signal components.
Claim 14
Dependent Claim
194 words
An acousto-electric surface wave signal-translating device comprising: an acoustic-surface-wave-propagating medium; input surface-wave transducer means coupled to said medium for impressing desired acoustic surface waves on said medium; output surface-wave transducer means spaced from said input transducer means, coupled to said medium and responsive to said desired acoustic surface waves for developing an electrical output signal; said device being subject to the generation of undesired acoustic surface waves in said medium and to the consequent development of undesired output signal components by said output transducer means in response to said undesired acoustic surface waves; and additional surface-wave transducer means spaced from said input and output transducer means, coupled to said medium at a location traversed by said desired acoustic surface waves, and responsive to acoustic surface waves therein for generating additional acoustic surface waves in said mEdium substantially in counterphase with said undesired acoustic surface waves at one of said transducers, and further including a load impedance coupled to said additional transducer means for establishing the amplitude and phase of said additional acoustic surface waves to substantially counteract said undesired acoustic surface waves and thereby effectively inhibit the development of said undesired output signal components.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-26 | 1975-01-25 | 1975-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-26 | 1979-01-25 | 1979-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-26 | 1983-01-25 | 1983-07-27 | $7700.00 | Window Closed / Lapsed |