US3757258A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High frequency filter apparatus
Assignee: HP Inc
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Filing: 1971-12-23
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Granted: 1973-09-04
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Expires: 1991-12-23
Abstract
Abstract An improved image-frequency rejection filter combines series resonant band-reject filtering at the image frequency with parallel resonant bandpass filtering at the carrier frequency.
Inventors
- 👤 R Dillman
- 👤 J Larsen
- 👤 R Tverdoch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:44
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/201; H01P1/203; H01P1/2039
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
249 words
Signal selective apparatus comprising: a first transmission line having a signal conductor and a reference conductor disposed in electromagnetically coupled relationship and having a characteristic impedance; a second transmission line having a signal conductor and a reference conductor disposed in electromagnetically coupled relationship and having a characteristic impedance; a signal port including a first conductor connected to the signal conductor of the first transmission line near one end thereof and including a second conductor connected to the reference conductor of the first transmission line; means connecting one end of the signal conductor of the second transmission line to the first conductor of the signal port and the reference conductor of the second transmission line to the second conductor of the signal port; a first reactance element connected between the reference conductor and the signal conductor of the first transmission line near the oPposite end thereof, the reactance of the element having a value with respect to the characteristic impedance of the first transmission line to establish series resonance therewith at a first frequency of signal appearing at said signal port; and a second reactance element connected between the reference conductor and the signal conductor of the second transmission line near the other end thereof, the reactance of the second element having a value in combination with the characteristic impedance of the second transmission line which establishes resonance with the combination of the transmission line and first reactance element at a second frequency of signal appearing at said signal port.
Claim 2
Dependent Claim
249 words
Signal selective apparatus comprising: a first transmission line having a signal conductor and a reference conductor disposed in electromagnetically coupled relationship and having a characteristic impedance; a second transmission line having a signal conductor and a reference conductor disposed in electromagnetically coupled relationship and having a characteristic impedance; a signal port including a first conductor connected to the signal conductor of the first transmission line near one end thereof and including a second conductor connected to the reference conductor of the first transmission line; means connecting one end of the signal conductor of the second transmission line to the first conductor of the signal port and the reference conductor of the second transmission line to the second conductor of the signal port; a first reactance element connected between the reference conductor and the signal conductor of the first transmission line near the oPposite end thereof, the reactance of the element having a value with respect to the characteristic impedance of the first transmission line to establish series resonance therewith at a first frequency of signal appearing at said signal port; and a second reactance element connected between the reference conductor and the signal conductor of the second transmission line near the other end thereof, the reactance of the second element having a value in combination with the characteristic impedance of the second transmission line which establishes resonance with the combination of the transmission line and first reactance element at a second frequency of signal appearing at said signal port.
Claim 3
Dependent Claim
37 words
Signal selective apparatus as in claim 1 wherein: the second frequency is higher or lower than said first frequency; and said first and second frequencies are within the range from approximately 200 MHz to approximately 1,000 MHz.
Claim 4
Dependent Claim
60 words
Signal selective apparatus as in claim 1 comprising a second conductor connected to said signal conductors of the first and second transmission lines adjacent the common connection of said first conductor to the signal conductors of the first and second transmission lines for providing an output conductor which is isolated from reactance of the first conductor of said signal port.
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) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |