Patent US3715674A successfully refreshed from Google Patents.
US3715674A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrically controlled reflection of acoustic surface waves
Assignee: SRI International Inc
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Filing: 1971-07-23
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Granted: 1973-02-06
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Expires: 1991-07-23
Abstract
Abstract A circuit is provided for tuning out the reactance established at the electrical port of an acoustical surface wave transducer thereby providing near perfect reflection of the acoustic surface waves. The variable impedance circuit, which is controlled electrically, besides a positive reactance generates a negative resistance that can be used to provide reflection and transmission gain for the surface waves.
Inventors
- 👤 A Bahr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:18
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/30; H03H9/42; H03H9/02; H03H9/125; H03H9/145; H03H9/14597; H03H9/423; H03H9/74; H03H9/76
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
66 words
In a surface acoustic delay line of the type wherein an input circuit applies a signal to a first transducer at the signal input end and a second transducer is at the location from which a reflection is desired, the improvement comprising: an electrically controlled variable impedance means connected to said second transducer for establishing a reactance which tunes out the reactance of the second transducer.
Claim 2
Dependent Claim
66 words
In a surface acoustic delay line of the type wherein an input circuit applies a signal to a first transducer at the signal input end and a second transducer is at the location from which a reflection is desired, the improvement comprising: an electrically controlled variable impedance means connected to said second transducer for establishing a reactance which tunes out the reactance of the second transducer.
Claim 3
Dependent Claim
66 words
In a surface acoustic delay line of the type wherein an input circuit applies a signal to a first transducer at the signal input end and a second transducer is at the location from which a reflection is desired, the improvement comprising: an electrically controlled variable impedance means connected to said second transducer for establishing a reactance which tunes out the reactance of the second transducer.
Claim 4
Dependent Claim
66 words
In a surface acoustic delay line of the type wherein an input circuit applies a signal to a first transducer at the signal input end and a second transducer is at the location from which a reflection is desired, the improvement comprising: an electrically controlled variable impedance means connected to said second transducer for establishing a reactance which tunes out the reactance of the second transducer.
Claim 5
Dependent Claim
35 words
In an acoustic delay line as recited in claim 1 wherein said variable impedance means includes means for providing a negative resistance for affecting the reflection characteristics and establishing transmission gain for said delay line.
Claim 6
Dependent Claim
25 words
An acoustic delay circuit as recited in claim 1 wherein the electrically controlled variable impedance meanS includes a transistor having an inverted common collector configuration.
Claim 7
Dependent Claim
68 words
A surface acoustic wave delay line circuit arrangement comprising a body of acoustic delay material having spaced therealong at desired locations, surface wave transducers, each surface wave transducer having connected thereto an electrically controlled variable impedance circuit, and means for setting the values of said variable impedances at desired values for establishing desired reflection and transmission characteristics for said body of acoustic delay material for acoustic surface waves.
Claim 8
Dependent Claim
68 words
A surface acoustic wave delay line circuit arrangement comprising a body of acoustic delay material having spaced therealong at desired locations, surface wave transducers, each surface wave transducer having connected thereto an electrically controlled variable impedance circuit, and means for setting the values of said variable impedances at desired values for establishing desired reflection and transmission characteristics for said body of acoustic delay material for acoustic surface waves.
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) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |