US3908137A
Expired / Lapsed
US
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Apparatus and method for triple transit signal cancellation in an acoustical surface wave device
Assignee: Magnavox Electronic Systems Co
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Filing: 1973-12-26
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Granted: 1975-09-23
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Expires: 1993-12-26
Abstract
Abstract Apparatus and method for reduction of triple transit signals generated by the interaction between acoustic surface waves and transducer elements in acoustic surface wave devices. Input transducers are positioned such that the transit time between a first input transducer and an output transducer is delayed by a quarter of a wavelength relative to the transit time between a second input transducer and the output transducer. The input signal to the second input transducer is delayed externally by a length of time equivalent to a quarter of a wavelength. The output transducer signals can therefore be combined to produce an enhanced output signal. Acoustic surface waves generated at an output transducer and returned to the output transducer after interaction with the first input transducer will be retarded two quarter wave lengths (one for each transit) as compared to acoustic surface simultaneously generated at an output transducer and returned to the output transducer after interaction with the second input transducer. Because of the phase relationship, the signals generated at the output transducers as a result of acoustic wave interactions with the two input transducers will cancel when combined.
Inventors
- 👤 Bill J Hunsinger
- 👤 Frederick Y Cho
- 👤 Brian B Fugit
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:03
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/02535; H03H9/02818; H03H9/02842; H03H9/0285; G; G10; G10K; G10K11/00; G10K11/36; H03H9/125; H03H9/145; H03H9/14502; H03H9/14508; H03H9/14544; H03H9/1455
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
159 words
Apparatus for processing electrical signals comprising: first delay means for delaying input electrical signals by a preselected period of time; and an acoustic surface wave device including, an acoustic-wave propagating medium, a first electroacoustic transducer coupled to said medium; a second electroacoustic transducer coupled to said medium; a third electroacoustic transducer coupled to said medium; said third transducer generating output electrical signals in response to interacting acoustic surface waves; said second electroacoustic transducer coupled to said delay means, said second transducer launching surface waves in response to said delayed input signals for interaction with said third transducer, wherein a portion of launched surface waves from said first transducer and said second transducer interact to generate undesired electrical signals; and a second delay means for delaying launched surface waves for substantially the same period as the first delay means, the second delay means being positioned to delay launched surface waves between the first electroacoustic transducer and the third electroacoustic transducer.
Claim 2
Dependent Claim
159 words
Apparatus for processing electrical signals comprising: first delay means for delaying input electrical signals by a preselected period of time; and an acoustic surface wave device including, an acoustic-wave propagating medium, a first electroacoustic transducer coupled to said medium; a second electroacoustic transducer coupled to said medium; a third electroacoustic transducer coupled to said medium; said third transducer generating output electrical signals in response to interacting acoustic surface waves; said second electroacoustic transducer coupled to said delay means, said second transducer launching surface waves in response to said delayed input signals for interaction with said third transducer, wherein a portion of launched surface waves from said first transducer and said second transducer interact to generate undesired electrical signals; and a second delay means for delaying launched surface waves for substantially the same period as the first delay means, the second delay means being positioned to delay launched surface waves between the first electroacoustic transducer and the third electroacoustic transducer.
Claim 3
Dependent Claim
28 words
Apparatus of claim 1 wherein said preselected period of delay is substantially equivalent to the time for propagation of one quarter of said predetermined wavelength in said medium.
Claim 4
Dependent Claim
49 words
Apparatus of claim 2 wherein said second transducer and said first transducer are substantially equidistant from said third transducer, said longer period for acoustic surface wave transit between said third transducer and said first transducer caused by material deposited on said medium between said first and said third transducer.
Claim 5
Dependent Claim
46 words
Apparatus of claim 2 wherein the longer period for acoustic surface wave transit between said third transducer and said first transducer is caused by a greater distance between said first transducer and said third transducer compared to a distance between said third and said second transducer.
Claim 6
Independent Claim
320 words
A device for processing electrical signals comprising: first delay means for electrically delaying an electrical signal for a preselected period of time; a substrate material for supporting propagation of acoustic surface waves; first transducer means for generating acoustic surface waves in said material in response to an electRical signal applied to a first terminal set and for producing a generated first signal in response to surface waves interacting with said first transducer means, said first transducer means coupled to said first delay means; second transducer means for generating acoustic surface waves in said material in response to an electrical signal applied to a second terminal set and for producing a generated second signal in response to surface waves interacting with said second transducer means, wherein the electrical signal applied to the first terminal set produces at least a portion of said generated second signal including a desired signal component resulting from a single transit of surface waves between said first and said second transducer means and an undesired signal component resulting from a triple transit of surface waves between said first and said second transducer means, wherein said electrical signal applied to the second terminal set produces said generated first signal including a desired signal component resulting from a single transit of surface waves between said second and said first transducer means and an undesired component resulting from a triple transit of surface waves between said second and said first transducer means; third transducer means for detecting acoustic surface waves in said material for producing a generated third signal in response to surface waves; and second delay means for delaying a transit of surface waves between said second and said third transducer means by said preselected period of time wherein application of an input electrical signal to said first delay means and to said second transducer means enhances a second signal desired component and inhibits the second signal undesired components.
Claim 7
Independent Claim
320 words
A device for processing electrical signals comprising: first delay means for electrically delaying an electrical signal for a preselected period of time; a substrate material for supporting propagation of acoustic surface waves; first transducer means for generating acoustic surface waves in said material in response to an electRical signal applied to a first terminal set and for producing a generated first signal in response to surface waves interacting with said first transducer means, said first transducer means coupled to said first delay means; second transducer means for generating acoustic surface waves in said material in response to an electrical signal applied to a second terminal set and for producing a generated second signal in response to surface waves interacting with said second transducer means, wherein the electrical signal applied to the first terminal set produces at least a portion of said generated second signal including a desired signal component resulting from a single transit of surface waves between said first and said second transducer means and an undesired signal component resulting from a triple transit of surface waves between said first and said second transducer means, wherein said electrical signal applied to the second terminal set produces said generated first signal including a desired signal component resulting from a single transit of surface waves between said second and said first transducer means and an undesired component resulting from a triple transit of surface waves between said second and said first transducer means; third transducer means for detecting acoustic surface waves in said material for producing a generated third signal in response to surface waves; and second delay means for delaying a transit of surface waves between said second and said third transducer means by said preselected period of time wherein application of an input electrical signal to said first delay means and to said second transducer means enhances a second signal desired component and inhibits the second signal undesired components.
Claim 8
Dependent Claim
20 words
The device of claim 5 wherein said second delay means is comprised of a metallized electrode deposited on said substrate.
Claim 9
Dependent Claim
45 words
The device of claim 5 wherein application of an input signal to said second transducer means enhances a desired signal component and inhibits an undesired signal component resulting from combining a generated third signal and a generated first signal delayed by said second delay means.
Claim 10
Dependent Claim
225 words
A signal processing device comprising: an acoustic-wave propagating medium; first transducer means responsive to a first input signal for launching in said medium acoustic surface waves related to a predetermined wavelength; second transducer means responsive to a second input signal for launching in said medium acoustic surface waves related to said predetermined wavelength; first delay means for delaying said first input signal to produce said second input signal, said first delay means delaying said first input signal by a preselected period of time; and third transducer means responsive to said acoustic waves from said first and said second transducer means to provide a desired output signal, wherein acoustic surface waves launched from said first transducer means are delayed relative to acoustic surface waves launched simultaneously by said second transducer means by a period of time substantially equal to the delay of the first delay means, wherein a portion of acoustic surface waves launched by said first transducer means which was reflected first from said third transducer means and then from said first transducer means produces an undesired signal in said third transducer means and wherein a portion of acoustic waves launched by said second transducer means which was reflected first by said third transducer means and then by said second transducer means are combined and substantially cancelled because of phase relationships of the reflected signals.
Claim 11
Dependent Claim
225 words
A signal processing device comprising: an acoustic-wave propagating medium; first transducer means responsive to a first input signal for launching in said medium acoustic surface waves related to a predetermined wavelength; second transducer means responsive to a second input signal for launching in said medium acoustic surface waves related to said predetermined wavelength; first delay means for delaying said first input signal to produce said second input signal, said first delay means delaying said first input signal by a preselected period of time; and third transducer means responsive to said acoustic waves from said first and said second transducer means to provide a desired output signal, wherein acoustic surface waves launched from said first transducer means are delayed relative to acoustic surface waves launched simultaneously by said second transducer means by a period of time substantially equal to the delay of the first delay means, wherein a portion of acoustic surface waves launched by said first transducer means which was reflected first from said third transducer means and then from said first transducer means produces an undesired signal in said third transducer means and wherein a portion of acoustic waves launched by said second transducer means which was reflected first by said third transducer means and then by said second transducer means are combined and substantially cancelled because of phase relationships of the reflected signals.
Claim 12
Dependent Claim
45 words
The signal processing device of claim 8 wherein at least a portion of delay between the first transducer means and the third transducer means is provided by deposition of a material on a surface of said medium between said first and said third transducer means.
Claim 13
Dependent Claim
50 words
The signal processing device of claim 8 wherein at least a portion of delay between the first tranSducer means and the third transducer means is provided by a distance between said first and said third transducer means being greater than a distance between said second and said third transducer means.
Claim 14
Dependent Claim
34 words
The signal processing device of claim 8 wherein said preselected period of time is substantially equal to one quarter the period of a frequency required to propagate acoustic surface waves at said predetermined wavelength.
Claim 15
Dependent Claim
79 words
The signal processing device of claim 8 wherein said first and said second transducer means are positioned on opposite sides of said third transducer means, and wherein a portion of surface waves launched by said first transducer means and reflected by said second transducer means produce a second undesired signal in said third transducer means, wherein a portion of surface waves launched by said second transducer means and reflected by said first transducer means inhibit said second undesired signal.
Claim 16
Dependent Claim
19 words
The signal processing device of claim 8 wherein said output signal and said first input signal can be reversed.
Claim 17
Independent Claim
223 words
A method for reducing undesired signals in acoustic surface wave devices originating from surface waves from an input electroacoustic transducer, reflected from an output electroacoustic transducer and reflected once again from said input transducer and interacting with said output transducer to produce said undesired signals, comprising the steps of: providing a first acoustic surface wave channel for traversal of surface waves between a first input electroacoustic transducer and said output transducer; providing a second acoustic surface wave channel for traversal of surface waves between a second input electroacoustical transducer and said output transducer, wherein traversal of acoustic surface waves of a predetermined wavelength requires a preselected period of time longer than traversal through said first channel by acoustic surface waves of said predetermined wavelength; applying an input signal to said second transducer; and applying said input signal delayed by substantially said preselected period to said first transducer, wherein acoustic waves generated by said first transducer and said second transducer generate a desired output signal in said output transducer, wherein said undesired output signals generated in said output transducer by a portion of first channel surface waves reflected by said output transducer and said first input transducer are inhibited signals in said output transducer generated by a portion of said second channel surface waves reflected from said output transducer and said second input transducer.
Claim 18
Independent Claim
223 words
A method for reducing undesired signals in acoustic surface wave devices originating from surface waves from an input electroacoustic transducer, reflected from an output electroacoustic transducer and reflected once again from said input transducer and interacting with said output transducer to produce said undesired signals, comprising the steps of: providing a first acoustic surface wave channel for traversal of surface waves between a first input electroacoustic transducer and said output transducer; providing a second acoustic surface wave channel for traversal of surface waves between a second input electroacoustical transducer and said output transducer, wherein traversal of acoustic surface waves of a predetermined wavelength requires a preselected period of time longer than traversal through said first channel by acoustic surface waves of said predetermined wavelength; applying an input signal to said second transducer; and applying said input signal delayed by substantially said preselected period to said first transducer, wherein acoustic waves generated by said first transducer and said second transducer generate a desired output signal in said output transducer, wherein said undesired output signals generated in said output transducer by a portion of first channel surface waves reflected by said output transducer and said first input transducer are inhibited signals in said output transducer generated by a portion of said second channel surface waves reflected from said output transducer and said second input transducer.
Claim 19
Dependent Claim
110 words
An electroacoustic surface wave device having means to substantially cancel undesired signals comprising: an acoustic surface wave medium; at least two input transducers; at least one output transducer; the at least two input transducers and the at least one output transducer being mounted on the medium; a delay means located between one of the at least two input transducers and the at least one output transducer so that when an input signal is applied to another of the at least two input transducers through a delay device having substantially the same amount of delay as the delay means then undesired signals within the electroacoustic surface wave device are substantially cancelled.
Claim 20
Dependent Claim
110 words
An electroacoustic surface wave device having means to substantially cancel undesired signals comprising: an acoustic surface wave medium; at least two input transducers; at least one output transducer; the at least two input transducers and the at least one output transducer being mounted on the medium; a delay means located between one of the at least two input transducers and the at least one output transducer so that when an input signal is applied to another of the at least two input transducers through a delay device having substantially the same amount of delay as the delay means then undesired signals within the electroacoustic surface wave device are substantially cancelled.
Claim 21
Dependent Claim
21 words
The electroacoustic surface wave device of claim 15 wherein the delay means is an electrode on the acoustic surface wave medium.
Claim 22
Dependent Claim
26 words
The electroacoustic surface wave device of claim 15 wherein the delay means delays a surface wave by a multiple of one quarter of its wave length.
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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) | 1978-09-22 | 1979-03-24 | 1979-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-22 | 1983-03-24 | 1983-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-22 | 1987-03-24 | 1987-09-23 | $7700.00 | Window Closed / Lapsed |