Patent US3566314A successfully refreshed from Google Patents.
US3566314A
Expired / Lapsed
US
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Crystal band-pass filter with controlled attenuation between passbands
Assignee: AT&T Inc
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Filing: 1968-02-27
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Granted: 1971-02-23
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Expires: 1988-02-27
Abstract
Abstract IN A CRYSTAL FILTER HAVING A PLURALITY OF PASSBANDS, RESISTANCES OF PREDETERMINED VALUE AS DERIVATED FROM AND RELATED TO SPECIFIC CIRCUIT PARAMETERS ARE INSERTED IN SERIES AND IN PARALLEL WITH THE CRYSTAL UNITS TO MAINTAIN THE PASSBANDS AND THE ATTENUATION BETWEEN THE PASSBANDS FLAT AND CONSTANT AND TO HOLD THE ATTENTUATION RATIO BETWEEN ALL OF THE PASSBANDS AND THE REGIONS OUTSIDE OF THE PASSBANDS AT A FIXED, PREDETERMINED LEVEL.
Inventors
- 👤 Frank R Bies
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:55
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/0023; H03H9/0095; 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) | 1974-02-22 | 1974-08-24 | 1975-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-22 | 1978-08-24 | 1979-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-22 | 1982-08-24 | 1983-02-23 | $7700.00 | Window Closed / Lapsed |