Patent US3087993A successfully refreshed from Google Patents.
US3087993A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Arrangement for the stereophonic reproduction of signals
Assignee: NORTH AMERICAN PHILLIPS COMPAN
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Filing: 1960-03-21
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Granted: 1963-04-30
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Expires: 1980-03-21
Abstract
No abstract record available.
Inventors
- 👤 Nicolaas Van Hurck
- 👤 Stumpers Frans Louis Hen Marie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:09
CPC Classifications
H; H04; H04H; H04H20/00; H04H20/86; H04H20/88
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
151 words
A CIRCUIT FOR THE STEREOPHONIC REPRODUCTION OF SIGNALS OF THE TYPE COMPRISING A SUM SIGNAL THAT IS THE SUM OF FIRST AND SECOND COHERENT STEREOPHONIC SIGNALS, AND A DIFFERENCE SIGNAL THAT IS THE DIFFERENCE OF SAID FIRST AND SECOND COHERENT STEREOPHONIC SIGNALS FREQUENCY MODULATED ON A SUBCARRIER WAVE, SAID CIRCUIT COMPRISING A TRANSMISSION NETWORK HAVING INPUT AND OUTPUT CIRCUITS, SAID NETWORK HAVING A TRANSMISSION FACTOR SUBSTANTIALLY INDEPENDENT OF FREQUENCY FOR SIGNALS OF THE FREQUENCY OF SAID SUM SIGNAL AND A SUBSTANTIALLY LINEAR RELATIONSHIP WITH FREQUENCY FOR SIGNALS OF THE FREQUENCY OF SAID SUBCARRIER WAVE, MEANS APPLYING SAID SUM AND DIFFERENCE SIGNALS TO SAID INPUT CIRCUIT, FIRST AND SECOND AMPLITUDE DETECTION DEVICES CONNECTED TO SAID OUTPUT CIRCUIT, SAID FIRST AND SECOND DETECTION DEVICES BEING CONNECTED WITH OPPOSITE CONDUCTIVITY WITH RESPECT TO SAID SUM SIGNAL, AND MEANS FOR DERIVING SAID FIRST AND SECOND STEREOPHONIC SIGNALS FROM SAID FIRST AND SECOND DETECTION DEVICES RESPECTIVELY.
Claim 2
Dependent Claim
151 words
A CIRCUIT FOR THE STEREOPHONIC REPRODUCTION OF SIGNALS OF THE TYPE COMPRISING A SUM SIGNAL THAT IS THE SUM OF FIRST AND SECOND COHERENT STEREOPHONIC SIGNALS, AND A DIFFERENCE SIGNAL THAT IS THE DIFFERENCE OF SAID FIRST AND SECOND COHERENT STEREOPHONIC SIGNALS FREQUENCY MODULATED ON A SUBCARRIER WAVE, SAID CIRCUIT COMPRISING A TRANSMISSION NETWORK HAVING INPUT AND OUTPUT CIRCUITS, SAID NETWORK HAVING A TRANSMISSION FACTOR SUBSTANTIALLY INDEPENDENT OF FREQUENCY FOR SIGNALS OF THE FREQUENCY OF SAID SUM SIGNAL AND A SUBSTANTIALLY LINEAR RELATIONSHIP WITH FREQUENCY FOR SIGNALS OF THE FREQUENCY OF SAID SUBCARRIER WAVE, MEANS APPLYING SAID SUM AND DIFFERENCE SIGNALS TO SAID INPUT CIRCUIT, FIRST AND SECOND AMPLITUDE DETECTION DEVICES CONNECTED TO SAID OUTPUT CIRCUIT, SAID FIRST AND SECOND DETECTION DEVICES BEING CONNECTED WITH OPPOSITE CONDUCTIVITY WITH RESPECT TO SAID SUM SIGNAL, AND MEANS FOR DERIVING SAID FIRST AND SECOND STEREOPHONIC SIGNALS FROM SAID FIRST AND SECOND DETECTION DEVICES RESPECTIVELY.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1966-04-29 | 1966-10-29 | 1967-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1970-04-29 | 1970-10-29 | 1971-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1974-04-29 | 1974-10-29 | 1975-04-30 | $7700.00 | Window Closed / Lapsed |