Patent US3868608A successfully refreshed from Google Patents.
US3868608A
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Surface wave filter
Assignee: GTE Sylvania Inc
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Filing: 1974-04-01
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Granted: 1975-02-25
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Expires: 1994-04-01
Abstract
Abstract A surface wave filter with symmetrical input and output transducers is shown. The input transducer has mirror image symmetry about a center line. The output transducers have mirror image symmetry about a line displaced one-fourth wavelength from the center line of the input transducer to provide differential output signals.
Inventors
- 👤 G Norman Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:08
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/0023; H03H9/0028; H03H9/0033; H03H9/0038; H03H9/02; H03H9/125; H03H9/145; H03H9/14544
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
91 words
A surface wave filter comprising: a substrate of piezoelectric material; an input transducer deposited on said substrate and having an input comb of electrodes and a common comb of electrodes with mirror image symmetry about a center line; and first and second output transducers deposited on said substrate on opposite sides of said input transducer and each having a common comb of electrodes and an output comb of electrodes with mirror image symmetry about a line displaced an integral number of wavelengths plus or minus one-fourth wavelength from said center line.
Claim 2
Dependent Claim
91 words
A surface wave filter comprising: a substrate of piezoelectric material; an input transducer deposited on said substrate and having an input comb of electrodes and a common comb of electrodes with mirror image symmetry about a center line; and first and second output transducers deposited on said substrate on opposite sides of said input transducer and each having a common comb of electrodes and an output comb of electrodes with mirror image symmetry about a line displaced an integral number of wavelengths plus or minus one-fourth wavelength from said center line.
Claim 3
Dependent Claim
34 words
A surface wave filter as defined in claim 1 including conductor means deposited on said substrate connecting said common comb of said input transducer to each of said common combs of said output transducers.
Claim 4
Dependent Claim
26 words
A surface wave filter as defined in claim 2 wherein the line of symmetry of said output transducers is displaced one-fourth wavelength from said center line.
Claim 5
Dependent Claim
99 words
In a frequency selective circuit for an intermediate frequency amplifier, a surface wave filter comprising: a substrate of piezoelectric material; an input transducer having an input comb of electrodes and a common comb of electrodes deposited on said substrate with mirror image symmetry about a center line; and first and second output transducers each having a common comb of electrodes and an output comb of electrodes deposited on said substrate on opposite sides of said input transducer with mirror image symmetry about a line displaced an integral number of wavelengths plus or minus one-fourth wavelength from said center line.
Claim 6
Dependent Claim
99 words
In a frequency selective circuit for an intermediate frequency amplifier, a surface wave filter comprising: a substrate of piezoelectric material; an input transducer having an input comb of electrodes and a common comb of electrodes deposited on said substrate with mirror image symmetry about a center line; and first and second output transducers each having a common comb of electrodes and an output comb of electrodes deposited on said substrate on opposite sides of said input transducer with mirror image symmetry about a line displaced an integral number of wavelengths plus or minus one-fourth wavelength from said center line.
Claim 7
Dependent Claim
34 words
A surface wave filter as defined in claim 4 including conductor means deposited on said substrate connecting said common comb of said input transducer to each of said common combs of said output transducers.
Claim 8
Dependent Claim
26 words
A surface wave filter as defined in claim 4 wherein the line of symmetry of said output transducers is displaced one-fourth wavelength from said center line.
Claim 9
Dependent Claim
38 words
A surface wave filter as defined in claim 6 wherein said intermediate frequency amplifier includes a differential amplifier connected to saiD first and second output transducers for rejecting common mode signals from said first and second output transducers.
References Cited (Backward Citations)
US3665211A
Cited
US3750027A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |