US3671673A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal switching circuit operable in response to a voice signal
Assignee: Iwatsu Electric Co Ltd
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Filing: 1971-04-06
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Granted: 1972-06-20
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Expires: 1991-04-06
Abstract
Abstract A signal switching circuit operable in response to a voice signal but not operable in response to an audible periodic signal or signals, in which a pair of signal convertors having different trigger levels from each other are provided to generate a first pulse train and a second pulse train in response to respective intersections of the instantaneous level of the voice signal with the different trigger levels. A switching circuit is switched to a desired state when a difference between respective number of pulses of the first pulse train and the second pulse train reaches a predetermined value.
Inventors
- 👤 Kozo Uchida
- 👤 Toshiyuki Tsuji
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:35
CPC Classifications
G; G10; G10L; G10L25/00; G10L25/78; H; H04; H04M; H04M19/00; H04M19/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
150 words
A signal switching circuit, comprising: input terminal means, for receiving at least a voice signal; first signal conversion means connected to said input terminal means for generating pulses of a first pulse train In response to at least every unidirectional intersection of the instantaneous level of the voice signal with a first trigger level; second signal conversion means connected to said input terminal means for generating pulses of a second pulse train in response to at least every unidirectional intersection of the instantaneous level of the voice signal with a second trigger level different from said first trigger level; comparator means connected to said first and second signal conversion means for detecting a difference between respective numbers of pulses of said first pulse train and said second pulse train; and switching means connected to said comparator means and switched to a desired state when said difference reaches a predetermined value.
Claim 2
Dependent Claim
150 words
A signal switching circuit, comprising: input terminal means, for receiving at least a voice signal; first signal conversion means connected to said input terminal means for generating pulses of a first pulse train In response to at least every unidirectional intersection of the instantaneous level of the voice signal with a first trigger level; second signal conversion means connected to said input terminal means for generating pulses of a second pulse train in response to at least every unidirectional intersection of the instantaneous level of the voice signal with a second trigger level different from said first trigger level; comparator means connected to said first and second signal conversion means for detecting a difference between respective numbers of pulses of said first pulse train and said second pulse train; and switching means connected to said comparator means and switched to a desired state when said difference reaches a predetermined value.
Claim 3
Dependent Claim
23 words
A signal switching circuit according to claim 1, in which each of said first and second signal conversion means comprises a monostable multivibrator.
Claim 4
Dependent Claim
25 words
A signal switching circuit according to claim 1, in which said comparator means comprises a capacitor for integrating a difference voltage corresponding to said difference.
Claim 5
Dependent Claim
29 words
A signal switching circuit according to claim 3, in which said switching means is switched when said integrated difference voltage reaches a threshold level corresponding to said predetermined value.
Claim 6
Dependent Claim
35 words
A signal switching circuit according to claim 1, in which said comparator means comprises a reversible counter, and in which said switching means is switched in response to a carry pulse of said reversible counter.
References Cited (Backward Citations)
US3215934A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |