US3588548A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital low pass filters
Assignee: Telephone Manufacturing Co Ltd
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Filing: 1969-01-21
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Granted: 1971-06-28
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Expires: 1989-01-21
Abstract
Abstract A LOW PASS FILTER WITH SHARP CUTOFF HAVING A BANDWIDTH VARIABLE AT WILL EMPLOYING DIGITAL CIRCUITRY.
Inventors
- 👤 Ioan Hugh Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:02
CPC Classifications
H; H03; H03H; H03H11/00; H03H11/02; H03H11/04; H03H11/0405
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) | 1974-06-27 | 1974-12-27 | 1975-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-27 | 1978-12-27 | 1979-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-27 | 1982-12-27 | 1983-06-28 | $7700.00 | Window Closed / Lapsed |