US3588352A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Howling elimination system for use in simultaneous two-way communicating device and a howlingless simultaneous two-way communicating device
Assignee: Individual
•
Filing: 1967-03-21
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Granted: 1971-06-28
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Expires: 1987-03-21
Abstract
Abstract HOWLING IN SIMULTANEOUS COMMUNICATING SYSTEM CAN BE ELIMINATED BY THE PROVISION, IN EACH OF THE PAIR OF TRANSMITTING-RECEIVING INSTRUMENTS, OF TWO MICROPHONES DISPOSED IN GEOMETRICALLY AND ELECTRICALLY SYMMETRICAL RELATION RELATIVE TO A LOUD SPEAKER, AND TWO INPUT TRANSFORMERS CONNECTED, FOR DIFFERENTIAL ACTION, TO SAID MICROPHONES SO AS TO FOLLOW SAID MICROPHONES SO THAT THE INPUT SIGNALS OF THE PORTIONS OF THE VOICE EMITTED FROM THE LOAD SPEAKER PICKED UP BY SAID MICROPHONES ARE INVERTED AND CENCELLED RELATIVE TO EACH OTHER BEFORE BEING APPLIED TO A SUCCEEDING AMPLIFIER.
Inventors
- 👤 Ichiro Yamawaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:46
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/60; H04M9/00; H04M9/08; H04M9/087; H04M9/10
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 |