US3560894A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bandpass filter
Assignee: International Standard Electric Corp
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Filing: 1967-07-27
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Granted: 1971-02-02
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Expires: 1987-07-27
Abstract
Abstract A CRYSTAL FILTER PROVIDES AN EXTREMLY SHARP BANDPASS OR CUT-OFF CHARACTERISTIC. TO OVERCOME THE CRYSTAL AND THE FILTERS INHERENT INTERNAL CHARACTERISTIC LIMITATIONS, IT IS ISOLATED BETWEEN TWO INDUCTOR AND CAPACITOR CIRCUITS, PREFERABLY HAVING UNEQUAL IMPEDANCES. ON THE INPUT SIDE, THE CAPACITOR IS IN SHUNT AND THE INDUCTOR IS IN SERIES WITH THE INPUT TERMINALS. ON THE OUTPUT SIDE, THE CAPACITOR IS IN SERIES AND THE INDUCTOR IS IN SHUNT WITH THE OUTPUT TERMINALS. THIS CONFIGURATION PROVIDES A FLEXIBILITY WHICH ENABLES A FILTER DESIGNER TO PROVIDE MANY SPECIES OF THE INVENTION.
Inventors
- 👤 Alfred L M Fettweis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:14
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/46; H03H9/54; H03H9/542
Claims Analysis
Total Claims: 0
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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) | 1974-02-01 | 1974-08-03 | 1975-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-01 | 1978-08-03 | 1979-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-01 | 1982-08-03 | 1983-02-02 | $7700.00 | Window Closed / Lapsed |